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Grade 8 Practice Test 4 Annotated

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Science Test

Mississippi Department of Education Office of Student Assessment

MST2 Grade 8 Practice Test 4 - Annotated Page 1 of 98

Grade 8

Strand Inquiry

Competency 1: Draw conclusions from scientific investigations including controlled

experiments.

PLD 1 a Proficient: Design, conduct, and analyze conclusions from an investigation

that includes using experimental controls.

DOK 3

1. Two students carried out an investigation in which they measured the evaporation rate

of water under different conditions. The following table summarizes their findings.

The students concluded that water evaporates most quickly at 85°F.

Why would a scientist question the validity of this conclusion?

A. More water evaporated at 95°F than at 85°F. B. The experiment did not control time of evaporation. C. The experiment did not control the initial volume of water. D. Temperature was a variable that should have been a constant.

Beaker Number 1

Temperature (ºF) 55

Starting Volume (mL) 45

Final Volume (mL) 30

Water Lost (mL) 15

Elapsed Time (hours) 24

2

65

50

30

20

24

3

75

50

20

30

24

4

85

55

15

40

24

5

95

45

10

35

24

Evaporation Rate of Water



C is the correct answer.

There are four different starting volumes in this experiment; however, the

variable was supposed to be temperature. By using different starting

volumes, a second variable is introduced, creating the possibility for data to

be unreliable. One initial volume should be used, and the experiment

should be run again to find new data.

A is not the correct answer.

Based on the data, more water actually evaporated at 85°F than at 95°F.

The difference between the starting volume and final volume at 85°F is

40 mL, but it is only 35 mL at 95°F.

B is not the correct answer.

The elapsed time in the table was twenty-four hours for each beaker, which

means the time was controlled.

D is not the correct answer.

Temperature was the variable being tested in this experiment. Therefore, it

is not a controlled variable and should not be held constant.



Grade 8

Strand Inquiry


experiments.

PLD 1 a Advanced: Evaluate the design of an investigation, including the design’s use

of experimental controls and the design’s effect on the conclusion.

DOK 3

Bandaging Bacteria

Some bacteria are harmful, such as Staphylococcus and Pseudomonas. These bacteria release toxins that burst open human cells. They rob the cell of glucose, which they use for energy. This allows the bacteria to reproduce very quickly and go on to attack more human cells. Some bacteria are helpful, such as E. coli. These bacteria are important to human bodies because they produce vitamin K. They also help protect human cells by blocking the growth of disease-causing bacteria. Chemical compounds called antibiotics are used to destroy harmful types of bacteria. However, these antibiotics can also destroy useful bacteria such as E. coli, which is used to make one type of vitamin K. Vitamin K is needed to clot blood.

Scientists are working to develop a new kind of bandage that helps fight infections caused by harmful bacteria. The bandage material contains tiny capsules that look like human cells. Inside the capsules are antibiotics. When capsules in the bandage material are attacked by bacteria, they release antibiotics that destroy the bacteria on contact.

For his science project, Ben investigated the bandage material using three different types of bacteria. He followed these steps:

1) Filled four Petri dishes with nutrient gel and labeled them 1 through 4

2) Placed a swab in the Staphylococcus bacteria and rubbed the swab onto Petri dish 1, placing the lid on tightly

3) Used the same swab to repeat step 2 with Pseudomonas in Petri dish 2, placing the lid on tightly



4) Used the same swab to repeat step 2 with E. coli in Petri dish 3, placing the lid on tightly

5) Did not place any bacteria in Petri dish 4, placing the lid on tightly

6) Placed all of the Petri dishes on a shelf, away from light and moisture for 24 hours

7) Placed equal amounts of the bandage material in each Petri dish


9) Repeated steps 1 through 8 for a total of three trials

The following table shows the results of the investigation.

Effects of Bandage Material on Bacterial Growth

PetriDish

Bacteria Added Description of Results after 36 Hours

1

2

3

4

Staphylococcus

Pseudomonas

E. Coli

None No bacteria present

Most bacteria destroyed Only small amount of bacteria remain





2. Based on the data, Ben concluded that the material would be useful in hospitals

because it reduces the number of harmful bacteria. Which of these describes Ben’s conclusion?

F. The conclusion is valid because it is supported by accurate results. G. The conclusion is valid because the investigation was repeated three times. H. The conclusion may be invalid because there was no control in the investigation. J. The conclusion may be invalid because the same swab was used for all three

bacteria.

J is the correct answer.

By using the same swab to apply all three bacteria samples, Ben

contaminated dishes 2 and 3 with more than one type of bacteria.

Therefore, he cannot be certain that it is the bandage material affecting the

number of bacteria because there is more than one variable introduced.

Ben did not control all variables other than the one being tested, the

independent variable. Therefore, the experiment has a design flaw that

affects the validity of the conclusions.

F is not the correct answer.

The accuracy of the results can be questioned because not all variables

other than the one being tested, the independent variable, were controlled.

This design flaw affects the validity of the conclusion.

G is not the correct answer.

Ben did perform multiple tests, but he used the same swab to apply all

three strands of bacteria to the dishes. Although it is part of a good

experimental design to perform multiple tests, controlling all variables other

than the one being tested is also important. Using the same swab

introduces more than one variable to each dish and affects the validity of

the conclusion.

H is not the correct answer.

Petri dish 4 contained no bacteria and can then be considered the control

group, which is necessary for comparison of results. Because Ben used the

same swab for all three dishes, the bacteria added to each dish was not

controlled and is the factor that affects the validity of the conclusion.



Grade 8

Strand Inquiry


experiments.

PLD 1 b Proficient: Distinguish between qualitative and quantitative observations and

make inferences based on observations.

DOK 3

3. Meg investigated the ability of different plants to decrease soil erosion. She performed

the following steps: 1) Planted five different species of plants, each in its own box 2) Set up the boxes in the same manner with one end of each box propped up at the

same angle 3) Placed a collection device at the bottom of each box to catch soil runoff 4) Released water over each box in the same manner 5) Measured the amount of soil runoff and recorded the appearance of the water The following table shows Meg’s data.

Based on both quantitative and qualitative data, which is a logical inference for this

investigation? A. The less able the plant was to prevent soil erosion, the clearer the water and the less soil

that eroded. B. The cloudier the water, the more soil that eroded and the less able the plant was to

prevent soil erosion. C. The clearer the water, the more soil that eroded and the better able the plant was to

prevent soil erosion. D. The better able the plant was to prevent soil erosion, the cloudier the water and the more

soil that eroded.

Soil in Water After Erosion Tests

A

22

Verycloudy

B

7

Mostlyclear

C

13

Cloudy

D

5

Mostlyclear

E

20

Verycloudy

Sample

Amount of Soil inWater Runoff (grams)

Appearance of Water



B is the correct answer.

This inference is based on both qualitative (the appearance of the water)

and quantitative (the amount of soil that eroded) observations. It is also

logical based on the data because more soil in the runoff is a sign of a

higher amount of soil erosion, meaning the plant was not able to prevent

soil erosion very well.


The inference is stated first. The sentence should be stated so that it is

clear that the results lead to the inference. Additionally, if a plant is less

able to prevent soil erosion, more soil would erode.

C is not the correct answer.

Clearer water would lead to an inference that the plant was better able to

prevent soil erosion. However, this would mean that less soil eroded.


The inference is stated first. The sentence should be stated so that it is

clear that the results lead to the inference. Additionally, if a plant is better

able to prevent soil erosion, less soil would erode.



Grade 8

Strand Inquiry


experiments.

PLD 1 b Basic: Identify an inference as being based on qualitative observations or

quantitative observations.

DOK 2

4. Ethan investigated which of three liquids had the highest boiling point. He put equal

amounts of liquid in different beakers and placed each beaker over the same amount of heat. To compare the liquids’ boiling points, he measured how long it took for each liquid to boil. The following table shows his results.

Ethan concluded that Liquid B had the highest boiling point.

Which of these led to this conclusion?

F. Qualitative observation of how hot the liquids got G. Quantitative measurement of how hot the liquids got H. Qualitative observation of how long it took for the liquids to boil J. Quantitative measurement of how long it took for the liquids to boil

Amount of Timefor Liquid to Boil

Time(seconds)

94

230

196

Liquid

A

B

C




The data shown in this table, the amount of time for the liquids to boil, is

based on numbers rather than descriptions. Therefore, the conclusion

Ethan made is based on quantitative measurements.


Ethan did not measure how hot the liquids got because he placed each

beaker over the same amount of heat. Additionally, this would be a

quantitative measurement rather than a qualitative observation.


This observation could not have led to Ethan’s conclusion. He did not

measure how hot the liquids got because he placed each beaker over the

same amount of heat.


The amount of time it took for the liquids to boil is numerical data, so this

represents quantitative measurements rather than qualitative observations.



Grade 8

Strand Inquiry


experiments.

PLD 1 c Proficient: Summarize data to show the cause and effect relationship

between qualitative and quantitative observations.

DOK 3

Roll with It

Tara and Cory investigated the motion of an object for a school science project. They

wanted to know whether ramp height affected the distance a toy car would roll. They used

a 30-centimeter long board for the ramp. For the first trial, they placed the board flat on the

floor. For the other trials, they propped the board up to 5-, 10-, and 15-centimeter heights.

For each trial, Tara placed the same 5-gram toy car at the top of the board. She released

the toy car and Cory measured the time, in seconds (s), the toy car traveled on the flat

floor until it stopped. Tara measured the distance the toy car traveled on the floor, in

centimeters (cm). Cory calculated the average speed during each trial in centimeters per

second . The following table shows all their data, and the graph shows the motion of

the toy car in Trial 2.

Toy Car Rolling Data

TrialRampangle

(degrees)

Distance(cm)

Time(s)

Rampheight(cm)

1

2

3

4

0.0

5.0

10.0

15.0

0.0

9.0

16.0

23.5

0.0

175.0

300.0

485.0

0.0

4.0

6.0

8.7

0 1 2 3 4 5

175

225

275

125

75

25

Time (s)

Dis

tan

ce (

cm)

Motion of Toy Carin Trial 2



While setting up their investigation, Cory placed the 7-gram stopwatch on the floor in front

of the ramp during Trial 3. Tara accidentally bumped the ramp, causing the toy car to roll

down the ramp and hit the stopwatch, which was at rest. They moved the stopwatch,

repeated the trial, and recorded the data, as shown above.

5. Based on the data, what is the cause-and-effect relationship between the ramps and the

toy cars? A. The farther the toy cars rolled, the longer the ramps. B. The slower the toy cars, the greater the ramps’ angle. C. The shorter the ramps, the greater the speed of the toy cars. D. The greater the ramps’ angle, the farther the toy cars rolled.

D is the correct answer.

The data show the positive relationship between ramp angle and distance the

toy cars rolled. This is an accurate summary of the data.


The same board was used for all trials, which means that the length of the

ramp was not changed, so the data do not show a relationship between these

variables.


The data show that the average speed, found by dividing distance by time,

increases as the ramp angle increases.


The same board was used for all trials, which means the length of the ramp

was not changed, so the data do not show a relationship between these

variables.



Grade 8

Strand Inquiry


experiments.

PLD 1 c Advanced: Predict the effect of summarized data.

DOK 3

6. Benito studied magnetic fields. He learned that a magnetic field is created when an

electric current passes through a wire. He found the following data showing how the magnetic field strength changes with distance from the wire.

Benito wanted to know the magnetic strength 10 centimeters away from the wire. Which summary of data provides a logical prediction for Benito?

F. • The magnetic field strength increases as the distance from the wire increases.

• The field strength at 10 centimeters will be 1 microtesla. G. • The magnetic field strength decreases as the distance from the wire increases.

• The field strength at 10 centimeters will be 5 microteslas. H. • The magnetic field strength decreases linearly as the distance from the wire increases.

• The field strength at 10 centimeters will be 1 microtesla. J. • The magnetic field strength increases linearly as the distance from the wire increases.

• The field strength at 10 centimeters will be 5 microteslas.

Strength of Magnetic Field

Distance from Wire(centimeters)

0.5

1.0

2.0

3.0

5.0

17

10

100

50

25

Magnetic Field Strength(microtesla)



G is the correct answer.

An inverse relationship between magnetic field strength and distance from

the wire is shown in the data. This relationship leads to a prediction that an

increase in distance from the wire by a factor of 2 results in a decrease in

field strength by a factor of 2.


The data do not support a direct relationship between distance from the

wire and magnetic field strength. Additionally, an increase in distance by a

factor of 2 will lead to a decrease in field strength by a factor of 2 rather

than 10.


The data do not support a linear relationship because for each equal

change in distance, the change in magnetic field strength is not the same.

Because the variables increase and decrease by the same factor, an

increase in distance by a factor of 2 will lead to a decrease in field strength

by a factor of 2 rather than 10.

J is not the correct answer.

The data support neither a direct nor a linear relationship. For each equal

increase in distance, the magnetic field strength decreases by a different

amount. However, the data do support the prediction that an increase in

distance by a factor of 2 will lead to a decrease in field strength by a factor

of 2.



Grade 8

Strand Inquiry


experiments.

PLD 1 d Proficient: Analyze evidence that is used to form explanations and draw

conclusions.

DOK 3

7. Bubbles form when an acid is mixed with baking soda, a base. Allie wanted to know

which household liquids are acids. She mixed several household liquids with two different white powders, baking soda and powdered sugar. The following data show her findings.

Which statement uses evidence from the table to form a conclusion? A. Water, milk, and dish soap must be acids because they did not form bubbles when

mixed with baking soda. B. Lemon juice and vinegar must be acids because they did not form bubbles when mixed

with powdered sugar. C. Water, milk, and dish soap must not be acids because they did not form bubbles when

mixed with baking soda. D. Lemon juice and vinegar must not be acids because they did not form bubbles when

mixed with powdered sugar.

LiquidForms Bubbles

with BakingSoda?

Forms Bubbleswith Powdered

Sugar?

Lemon juice

Water

Milk

Vinegar

Dish soap

Yes

No

No

Yes

No

No

No

No

No

No




The observations recorded in the table are accurately summarized. Given the

information that bubbles form when an acid is mixed with baking soda, it can

be concluded that any substances that do not form bubbles with baking soda

are not acids.


The observations are accurately summarized, but an incorrect conclusion is

drawn. Water, milk, and dish soap did not form bubbles with baking soda and

are therefore not acids.


This conclusion is based on the wrong set of observations. The information

given about acids refers to forming bubbles with baking soda, not powdered

sugar. Any substances that formed bubbles when mixed with baking soda

would be considered acids.


This conclusion is based on the wrong set of observations. The information

given about acids refers to forming bubbles with baking soda, not powdered

sugar. Any substances that did not form bubbles when mixed with baking

soda would not be considered acids.



Grade 8

Strand Inquiry


experiments.

PLD 1 d Basic: Identify evidence that supports an explanation or conclusion.

DOK 1

8. Jared investigated chemical reactions based on smell, color change, and release of

bubbles. What type of evidence would support any conclusion Jared makes?

F. An observation G. An estimation H. A calculation J. A measurement

F is the correct answer.

Jared used his senses to collect the evidence. Using the senses to collect

data is equivalent to making observations.


Estimations are calculated approximations based on numerical data. No

numerical data were gathered in this investigation.


Calculations are based on numerical data. No numerical data were gathered

in this investigation.


Measurements produce numerical data. No numerical data were gathered in

this investigation.



Grade 8

Strand Inquiry


experiments.

PLD 1 e Proficient: Develop a logical argument defending conclusions of an

experimental method.

DOK 3

9. A scientist measured the amounts of sulfurous gases near three active volcanoes and

three extinct volcanoes. He found that the areas near the active volcanoes had higher levels of sulfurous gases. Areas near the extinct volcanoes had limited amounts of sulfurous gases. The scientist concluded that an increase in sulfurous gases in the air surrounding a volcano is an indicator that a volcano is still active. Which of these is a logical argument defending the scientist’s conclusion?

A. He found little evidence that active volcanoes will become extinct. B. He did not take any samples from volcanoes that had erupted very recently. C. He found little evidence that extinct volcanoes produce sulfurous gases. D. He did not test any areas where there were not any volcanoes, active or extinct.


This argument presents a fact (areas near the extinct volcanoes had limited

amounts of sulfurous gases) that supports the scientist’s conclusion (an

increase in sulfurous gases in the air surrounding a volcano is an indicator

that a volcano is still active).


This argument does not logically defend the conclusion based on the

investigation given. The scientist did not measure the amount of sulfurous

gases near the volcanoes over an extended period of time.


This argument does not defend the scientist’s conclusion. Information

presented in the investigation does not support this argument.


This argument does not defend the scientist’s conclusion. The comparison of

levels between extinct and active volcanoes does not require testing of air not

in the vicinity of volcanoes.



Grade 8

Strand Inquiry


experiments.

PLD 1 e Advanced: Justify whether an argument defending a conclusion is logical.

DOK 3

10. A tsunami is a powerful ocean wave caused by an earthquake. A tsunami rises greatly

in height as it nears land. Max used a tank of water to simulate the action of a tsunami. The following diagram shows his device.

Max concluded that a tsunami rises higher as it nears land because the water

becomes shallower closer to land. Which statement provides a logical defense for Max’s conclusion?

F. The simulated wave was made to be as powerful as possible. G. The tank was shallow enough to simulate the ocean near the shore. H. The tank had enough water in it to accurately simulate ocean waves. J. The bottom of the tank sloped upward at one end just like the bottom of the ocean near

the shore.

Earthquake-simulating

Device

Tsunami Tank

LandWater




This answer choice provides evidence that can be gathered from the

information given (specifically the diagram) as well as logical reasoning to

support the conclusion.


The power of the simulated wave was never indicated in this investigation and

is not relevant to the conclusion, so an argument based on this does not

provide support for the conclusion.


It was not the tank that got shallower closer to land; it was the water. This

argument does not provide reasoning that logically supports the conclusion.


The amount of water in the tank was never indicated in this investigation and

is not relevant to the conclusion, so an argument based on this does not

provide support for the conclusion.



Grade 8

Strand Inquiry


experiments.

PLD 1 f Proficient: Develop a logical argument to explain why perfectly designed

solutions do not exist.

DOK 3

11. Soils contain chemical nutrients that help plants grow. Different plants require

different amounts of nutrients. Scientists can test soil samples to determine how much of certain chemical nutrients are present. A manufacturer wants scientists to develop a soil in which any kind of plant could grow equally well. Which statement explains whether the ability to make this type of soil is possible?

A. Yes, most soils are those in which any kind of plant could grow. B. No, there is no way to tell what nutrients are needed by any kind of plant. C. Yes, a mixture of the soils that contained all the nutrients could nourish any plant. D. No, a soil in which certain kinds of plants grow well might not be as good for other types

of plants.


Because the nutrients that support one plant may inhibit growth of another, it

is not likely that scientists would be able to find a soil that will allow all plants

to grow equally well. Therefore, this answer choice supports the idea that

perfectly designed solutions do not exist.


Although many soils may support the growth of several different types

of plants, it cannot be assumed that most soils could support all plant types.


It may be possible to determine what nutrients are needed by any kind of

plant, but it is not likely that scientists would be able to create a single soil to

accommodate the needs of all plants.


Because the nutrients that promote one plant’s growth may inhibit another

plant’s growth, it is not likely that scientists would be able to create a soil that

would support all kinds of plant growth if it contains all possible nutrients.



Grade 8

Strand Inquiry


experiments.

PLD 1 g Proficient: Justify a scientist’s need to revise conclusions after encountering

new experimental evidence that does not match existing

explanations.

DOK 3

12. Until recently, a certain type of fossil in rock beds was thought to be about 10,000

years old. A new, more accurate way of dating rock samples shows that it is actually 40,000 years old. However, this new evidence does not match scientists’ current explanations for how this species came to the area. Why should scientists revise their current explanations for how this species came to the area?

F. Fossils that are older than 10,000 years are extremely rare. G. Newer explanations are more correct than older explanations. H. The current explanations were based on less-accurate dating methods. J. Revising explanations every few years is a part of the scientific method.

H is the correct answer.

This response supports the idea that because of advances in technology and

science, scientists often need to investigate further and revise conclusions

after encountering evidence from more accurate research.


This response supports the older conclusion and does not provide a reason to

revise current explanations to support new findings.


A logical justification for revising findings is not provided. Scientists should

revise current explanations after investigating new findings and performing

further research when there is a contradiction to older explanations.


Scientists revise explanations when presented with newer, more accurate

evidence rather than at specific time intervals.



Grade 8

Strand Inquiry


experiments.

PLD 1 h Proficient: Analyze different ideas and recognize the skepticism of others as

part of the scientific process in considering alternative conclusions.

DOK 3

13. Dan wanted to know whether plants grow best in sunlight or artificial light. He set up

an investigation, making sure each plant received the same amount of light for the same amount of time. The following diagram shows his setup.

Dan found that the outside plants grew one inch taller than the inside plants. He

concluded that sunlight is better for plant growth than artificial light. A classmate, Carlos, is skeptical of Dan’s conclusion. Carlos thinks that Dan did not control other conditions that the plants grew under, such as temperature and available water. Which of these describes how Dan should respond to Carlos’s skepticism?

A. Dan should revise his original conclusion to match Carlos’s predictions about

temperature and air quality. B. Dan should dismiss Carlos’s criticism of his methods because Carlos did not carry out

the original experiment. C. Dan should invite Carlos to run the exact same experiment again to confirm that the

original conclusions are valid. D. Dan should run new tests to include other variables that Carlos mentioned to confirm

that the original conclusions are valid.

Group 1: Outside Group 2: Inside

Artificial lightSunlight




This response supports the idea that the skepticism of others is a necessary

part of the scientific process. Dan should address Carlos’s concerns by

running new tests in order to confirm the validity of his results and to allow for

alternative conclusions if necessary.


Carlos did not make any predictions. Rather, he presented skepticism that is a

necessary part of ensuring valid results. Dan should address Carlos’s

concerns by running additional tests.


Skepticism from others is a necessary part of the scientific process and

should be addressed to ensure valid results and to allow for alternative

conclusions if necessary.


This is not a logical response to Carlos’s skepticism. Because Carlos is

questioning part of the experimental design, running the same experiment

again would not address his concerns.



Grade 8

Strand Inquiry


experiments.

PLD 1 h Advanced: Evaluate arguments based upon the scientific process for ideas

presented as alternative conclusions.

DOK 3

14. When Alfred Wegener first proposed his theory of continental drift, most earth

scientists did not immediately accept it. Many expressed skepticism because the theory did not explain what force was strong enough to move continents. Later, scientists investigating continental drift found evidence that explained how continents are able to move. Plate tectonics, which grew from the theory of continental drift, now explains how continents move over time. How was the initial skepticism of earth scientists useful to the scientific process?

F. Skeptical comments showed that continental drift was not a correct explanation of

Wegener’s observations. G. The skeptics kept people from forgetting about earlier observations that did not support

continental drift. H. The scientists who were skeptical kept earth science from changing views too rapidly. J. The skeptics raised questions that became the starting point for new investigations.


Skepticism was useful to the scientific process because new investigations

arose in response to questions raised about the theory of continental drift, and

those new investigations led to the new theory of plate tectonics.


No reason is offered as to why the initial skepticism was useful to the scientific

process. Skepticism alone does not mean an explanation is incorrect.



process. The information provided does not mention skeptics keeping people

from forgetting about earlier observations that did not support continental drift.



process. The information provided does not mention scientists who kept earth

science from changing views too rapidly. Skepticism should contribute toward

a useful check-and-balance process of inquiry, not slow down the process.



Grade 8

Strand Inquiry


experiments.

PLD 1 h Basic: Recognize appropriate scientific skepticism when reviewing

alternative conclusions.

DOK 2

Bandaging Bacteria

















PetriDish


1

2

3

4

Staphylococcus

Pseudomonas

E. Coli







15. Ben presented his investigation to his lab partner, Kate. Kate is skeptical of the

results and listed the following concerns: 1) The results were repeated three times. 2) Ben used the same swab in three different bacteria. 3) Only one kind of bandage material was investigated. 4) Ben did not investigate other types of harmful bacteria. Which of Kate’s concerns support her skepticism?

A. 1 and 2 only B. 2 and 4 only C. 1, 2, and 3 only D. 1, 3, and 4 only


Both the second and fourth concerns support Kate’s skepticism. Using the

same swab in three different bacteria is reason for concern of

contamination in dishes 2 and 3. This could then introduce variables other

than the one being tested, reducing the validity of the data. Additionally,

there are many different strands of harmful bacteria, so the results from

only three cannot be generalized to all strands.


The first concern does not support Kate’s skepticism. Repetition of results

is part of good experimental design.


The first and third concerns do not support Kate’s skepticism. Repetition of

results is part of good experimental design. Additionally, it would not be

appropriate for Ben to test more than one type of bandage material since

the point of his investigation was to test a specific bandage material.


The first and third concerns do not support Kate’s skepticism. Repetition of

results is part of good experimental design. Additionally, it would not be

appropriate for Ben to test more than one type of bandage material since

the point of his investigation was to test a specific bandage material.



Grade 8

Strand Physical Science

Competency 2: Apply concepts relating to an understanding of chemical and physical

changes, interactions involving energy, and forces that affect motion of objects.

PLD 2 a Proficient: Identify patterns found in chemical symbols, formulas, reactions,

and equations that apply to the law of conservation of mass.

DOK 1

16. The following equation represents a balanced chemical reaction.

2Al2O3 + 3C 4Al + 3CO2 According to the law of conservation of mass, how many aluminum atoms will be

produced if 1,000 molecules of aluminum oxide are used in the reaction? F. 500 G. 1,000 H. 2,000 J. 4,000


From the balanced equation given, the ratio of aluminum oxide to aluminum

(Al2O3:Al) is 2:4 or 1:2. Therefore, twice the number of aluminum oxide

molecules used gives the number of aluminum atoms produced.


This is the number of aluminum oxide (Al2O3) molecules that are used if 1,000

atoms of aluminum (Al) are produced.


If 1,000 molecules of a reactant are used, then 2,000 atoms will be produced,

not 1,000. Because the ratio for this reactant and product is actually 1:2, twice

as many aluminum atoms will be produced.


If 1,000 molecules of a reactant are used, then 2,000 atoms will be produced,

not 4,000. Because the ratio is 2:4 rather than 1:4, twice the number of

aluminum oxide molecules used gives the number of aluminum atoms

produced.



Grade 8




PLD 2 a Advanced: Balance chemical equations to illustrate the law of conservation

of mass.

DOK 2

17. The following chemical equation shows the incomplete formula for burning methanol.

The question mark represents the unknown number of oxygen (O2) molecules.

2CH3OH + ?O2 2CO2 + 4H2O How many molecules of O2 are needed to balance this chemical equation? A. 1 B. 3 C. 5 D. 6


The number of atoms of oxygen for each molecule in the equation can be

found by multiplying the coefficient on the molecule and the subscript on the

oxygen atom. Then, the atoms of oxygen from each molecule on each side

are added together. This produces eight atoms of oxygen on the reactant side

and eight atoms of oxygen on the product side.


A coefficient of 1 on the oxygen molecule would mean that 4 atoms of oxygen

would be present on the reactant side and 8 atoms of oxygen would be

present on the product side, which is an unbalanced equation.


A coefficient of 5 on the oxygen molecule would mean that 12 atoms of

oxygen would be present on the reactant side and 8 atoms of oxygen would

be present on the product side, which is an unbalanced equation.


A coefficient of 6 on the oxygen molecule would mean that 14 atoms oxygen

would be present on the reactant side and 8 atoms of oxygen would be

present on the product side, which is an unbalanced equation.



Grade 8




PLD 2 a Basic: Identify the chemical symbols, formulas of common substances, or

reactions used in a balanced equation.

DOK 1

18. The following chemical equation shows the process of photosynthesis.

6CO2 + 6H2O C6H12O6 + 6O2 What is the common name of C6H12O6? F. Sugar G. Water H. Table salt J. Baking soda


The chemical formula shown is for glucose, which is also known as sugar and

is one of the products of photosynthesis.


The chemical formula for water is H2O. Water is one of the reactants, not a

product, in photosynthesis.


The chemical formula for table salt is NaCl. This substance is not involved in

photosynthesis and is not present in the equation.


The chemical formula for baking soda is NaHCO3. This substance is not

involved in photosynthesis and is not present in the equation.



Grade 8




PLD 2 b Proficient: Predict the properties and interactions of given elements using the

periodic table of the elements.

DOK 2

19.

Leroy combines magnesium (Mg) and fluorine (F). Based on the periodic table, which statement describes the interaction of these two elements?

A. Mg is a metal and F is a nonmetal that forms an ionic bond. B. Mg is a nonmetal and F is a metal that forms an ionic bond. C. Mg is a metal and F is a metal that forms a covalent bond. D. Mg is a metalloid and F is a nonmetal that forms a covalent bond.

1

HHydrogen

1.01

2

HeHelium

4.00

3

LiLithium

6.94

4

BeBeryllium

9.01

5

BBoron

10.81

6

CCarbon

12.01

7

NNitrogen

14.01

8

OOxygen

16.00

9

FFluorine

19.00

10

NeNeon

20.18

11

NaSodium

22.99

12

MgMagnesium

24.31

13

AlAluminum

26.98

14

SiSilicon

28.09

15

PPhosphorus

30.97

16

SSulfur

32.07

17

ClChlorine

35.45

18

ArArgon

39.95

19

KPotassium

39.10

20

CaCalcium

40.08

21

ScScandium

44.96

22

TiTitanium

47.88

23

VVanadium

50.94

24

CrChromium

52.00

25

MnManganese

54.94

26

FeIron

55.85

27

CoCobalt

58.93

28

NiNickel

58.69

29

CuCopper

63.55

30

ZnZinc

65.39

31

GaGallium

69.72

32

GeGermanium

72.61

33

AsArsenic

74.92

34

SeSelenium

78.96

35

BrBromine

79.90

36

KrKrypton

83.80

Group

Period

1

2

3

4

5

6

7

1

2

3 4 5 6 7 8 9 10 11 12

13 14 15 16 17

18

37

RbRubidium

85.47

38

SrStrontium

87.62

39

YYttrium

88.91

40

ZrZirconium

91.22

41

NbNiobium

92.91

42

MoMolybdenum

95.94

43

TcTechnetium

98.00

44

RuRuthenium

101.07

45

RhRhodium

102.91

46

PdPalladium

106.42

47

AgSilver

107.87

48

CdCadmium

112.41

49

InIndium

114.82

50

SnTin

118.71

51

SbAntimony

121.76

52

TeTellurium

127.60

53

IIodine

126.91

54

XeXenon

131.29

55

CsCesium

132.91

56

BaBarium

137.33

57

LaLanthanum

138.91

72

HfHafnium

178.49

73

TaTantalum

180.95

74

WTungsten

183.85

75

ReRhenium

186.21

76

OsOsmium

190.20

77

IrIridium

192.22

78

PtPlatinum

195.08

79

AuGold

196.97

80

HgMercury

200.59

81

TlThallium

204.38

82

PbLead

207.20

83

BiBismuth

208.96

84

PoPolonium

208.98

85

AtAstatine

210.00

86

RnRadon

222.00

87

FrFrancium

223.00

88

RaRadium

226.00

89

AcActinium

227.03

104

RfRutherfordium

(261)

105

DbDubnium

(262)

106

SgSeaborgium

(263)

107

BhBohrium

(264)

108

HsHassium

(265)

109

MtMeitnerium

(268)

Periodic Table of Elements



A is the correct answer.

Mg is on the left side of the periodic table and has a low electronegativity. F is

on the right side of the periodic table and has a high electronegativity.

Therefore, Mg is a metal, and F is a nonmetal. When they interact, Mg and F

will form an ionic bond because when a metal and a nonmetal form a bond,

the metal loses electrons while the nonmetal gains electrons due to the large

difference in their electronegativities.


Mg is on the left side of the periodic table and has a low electronegativity.

Elements that have very low electronegativities (and therefore have a

tendency to lose electrons) are classified as metals. F is on the right side of

the periodic table and has a high electronegativity. Elements that have very

high electronegativities (and therefore have a tendency to gain electrons) are

classified as nonmetals.


Two metals do not generally interact. Because F has a large electronegativity,

it is a nonmetal rather than a metal. Because of the large difference in their

electronegativities, Mg will lose electrons while F gains electrons, forming an

ionic bond.


Mg is a metal rather than a metalloid because it is on the far left side of the

periodic table and has a very low electronegativity. Metalloids are generally

found along the “stair-step” line that separates metals from nonmetals on the

periodic table. Additionally, metalloids have characteristics, such as

electronegativity, between that of metals and nonmetals. When Mg and F

interact, an ionic bond will be formed because of their large difference in

electronegativities.



Grade 8




PLD 2 b Basic: Use the periodic table to identify the properties of an element or a

simple compound.

DOK 1

20. Christy is studying sodium in the following periodic table of elements.

She makes the following list of possible properties for sodium: • Symbol is Na • Is a transition metal • Atomic number is 11 • Has one valence electron Which of these should Christy remove from this list?

F. Symbol is Na G. Is a transition metal H. Atomic number is 11 J. Has one valence electron

Sodium in thePeriodic Table of Elements

1

2

3

4

5

6

7

1Group

Period

2

3 4 5 6 7 8 9 101112

1314151617

1811

NaSodium

22.99




Transition metals are located in the short columns in the center of the periodic

table. This consists of columns 3 through 12. Sodium is a main group element

in the first column on the periodic table. The elements in this column are

considered alkali metals, not transition metals.


From the periodic table shown, the symbol for sodium is Na. The elemental

symbol is a capital letter that is sometimes, but not always, followed by a

lowercase letter and is located in the center of the box containing the

information for the element.


The atomic number is the number located above the elemental symbol in the

box containing the information for the element. From the periodic table shown,

this number is 11.


Sodium is located in the first column of the periodic table. All elements in this

column have one valence electron.



Grade 8




PLD 2 c Proficient: Distinguish the motion of an object by its position, direction of

motion, speed, and acceleration and represent resulting data in

graphic form in order to make a prediction.

DOK 2

Roll with It












TrialRampangle

(degrees)

Distance(cm)

Time(s)

Rampheight(cm)

1

2

3

4

0.0

5.0

10.0

15.0

0.0

9.0

16.0

23.5

0.0

175.0

300.0

485.0

0.0

4.0

6.0

8.7

0 1 2 3 4 5

175

225

275

125

75

25

Time (s)

Dis

tan

ce (

cm)








21. If the Trial 2 toy car had not stopped rolling and had continued in a straight line, how

far would the car have rolled at 5 seconds? A. 200 cm B. 225 cm C. 250 cm D. 275 cm


The graph shows that with each second, the toy car traveled 50 cm. At 4 s,

the toy car traveled 175 cm; 175 cm 50 cm 225 cm.


The graph shows that with each second, the toy car traveled 50 cm. At 200

cm, the time that the toy car traveled is 4.5 s, not 5 s.



cm, the time that the toy car traveled is 5.5 s, not 5 s.



cm, the time that the toy car traveled is 6 s, not 5 s.



Grade 8




PLD 2 c Advanced: Evaluate the motion of two or more objects to predict the effects of

a collision.

DOK 3

22. The following diagram shows the direction of motion of two objects of equal mass just

before they collide.

Which diagram shows the direction of motion of the two objects after they have

collided?

F.

H.

G.

J.




This is an example of conservation of momentum in an elastic collision. The

objects will collide, and an equal amount of energy will transfer between them,

causing each object to change its initial direction and move in the same

original direction as the object that collided with it.


The proper angle in which the collided objects will travel is not shown. They

will not move in straight, parallel lines.


Although the objects will travel away from each other, the vertical component

of their travel is not shown. They will not move in a straight line in opposite

directions from each other.


This response does not demonstrate the proper angle in which the collided

objects will travel. They will move apart but will not change direction in the

vertical plane because conservation of momentum must be followed.



Grade 8




PLD 2 d Proficient: Relate how electrical energy transfers through electric circuits,

generators, and power grids, including the importance of

contributions from Mississippi companies.

DOK 2

23. The following image shows Device X, found in a power grid system.

What is the role of this device within the electrical grid system? A. It is a generator that produces the current needed inside the home. B. It is a distributor that diverts power from the distribution line to the home. C. It is a transformer that reduces the voltage between the power line and the home. D. It is a regulator that limits the amount of electric power in the wire to the home.

Device X




The transformer steps down, or reduces, the voltage so that it is safe to enter

the home. The device shown is connected to power lines that supply

electricity to homes and performs this function.


The generator is located at the beginning of the power grid and is what

produces the electricity that flows through the grid. The device shown is

connected to power lines that supply electricity to homes and is therefore in a

different part of the power grid system.


The distributor is located at the substation and is what steps down the voltage

to a distribution level. The device shown is a transformer that will step down

the electricity once more before entering the home.


The regulator connects to the wires from the power lines and prevents

hazardous high- or low-voltage conditions. The device indicated is the larger,

cylindrical structure known as the transformer, and the regulators are the

smaller, spiral-shaped structures.



Grade 8




PLD 2 d Advanced: Predict the outcome (positive or negative) of altering one

component of the power grid system.

DOK 3

24. A customer on a grid system installed a wind turbine.

What is the effect of this wind turbine on the entire power grid?

F. The addition of the turbine affects the customer but not the rest of the grid. G. The excess power would flow in the wrong direction in the grid, reducing the total

available power. H. The unused electric power can be added to the grid, increasing the power available to

other customers. J. The added power would overload the power grid and trip circuit breakers at the nearest

power substation.


The excess energy produced by the turbine will need somewhere to go and

will therefore flow into the rest of the grid. When this happens, the power

available to anyone else connected to the grid will increase.


The turbine can affect the rest of the grid if there is excess power over what

the customer is currently using. Additional energy produced will flow into the

power grid.


The addition of the turbine will increase the total available power. At times

when the turbine is producing more power than the customer is using, that

additional power will flow into the power grid.


A single turbine will not produce enough energy to overload the power grid.

The energy available to other customers in the grid will simply increase.



Grade 8




PLD 2 e Proficient: Contrast various components of the electromagnetic spectrum

(e.g., infrared, visible light, ultraviolet) and predict their impacts

on living things.

DOK 2

25. Infrared light is often used in reptile habitats.

Which of these explains how a reptile benefits from infrared light?

A. Infrared light destroys bacteria and other microorganisms. B. Infrared light increases the body temperature of the animals. C. Infrared light makes it possible for reptiles to see their surroundings. D. Infrared light makes it possible for humans to see the animals in their natural habitat.


Reptiles are cold-blooded and absorb infrared light through their skin.

Infrared light bulbs are needed to supply this light to reptiles housed indoors.


Infrared light can dry out bacteria, but this is not the case with

microorganisms such as protists and fungi.


Some reptiles can see infrared light, but this is not the case with all reptiles.

In addition, reptiles are able to view their surroundings in visible light without

the aid of infrared light.


Humans are unable to see infrared light. In addition, humans are able to view

animals in visible light.



Grade 8




PLD 2 e Basic: Identify components of the electromagnetic spectrum.

DOK 1

26. Ella is learning about different types of electromagnetic radiation. She makes the

following list about one frequency of radiation: • Can damage cells of living things • Blocked by Earth’s ozone layer Which type of radiation does Ella’s list describe?

F. Infrared G. Microwave H. Ultraviolet J. Visible


Ultraviolet radiation has high energy with the ability to damage the cells of

living things and is considered hazardous in high doses. This type of radiation

is blocked by Earth’s ozone layer.


Infrared radiation is a type of low-frequency radiation with energy less than

that of visible light. It is not likely that radiation with low energy would damage

the cells of living things unless under prolonged exposure. Additionally, the

ozone layer is transparent to infrared but opaque to ultraviolet radiation.


Microwaves are a type of low-frequency radiation with energy less than that

of visible light. It is not likely that radiation with low energy would damage the

cells of living things. The ozone layer is transparent to microwave radiation.


Visible light does not have sufficient energy to be likely to damage the cells of

living things. Additionally, the ozone layer is transparent to visible light.



Grade 8




PLD 2 f Proficient: Recognize Newton’s Three Laws of Motion and identify situations

that illustrate each law (e.g., inertia, acceleration, action, reaction

forces).

DOK 2

Roll with It












TrialRampangle

(degrees)

Distance(cm)

Time(s)

Rampheight(cm)

1

2

3

4

0.0

5.0

10.0

15.0

0.0

9.0

16.0

23.5

0.0

175.0

300.0

485.0

0.0

4.0

6.0

8.7

0 1 2 3 4 5

175

225

275

125

75

25

Time (s)

Dis

tan

ce (

cm)








27. Which description applies to the toy car on Trial 1? A. An object at rest will stay at rest. B. For every action, there is an equal and opposite reaction. C. The rate at which an object falls is dependent upon the height from which the object is

dropped. D. The force needed to move an object is dependent upon the mass and acceleration of

the object.


Newton’s first law of motion states that an object will continue to move at a

constant velocity unless acted on by an unbalanced force. The car in Trial 1

maintains a constant velocity of zero throughout the entire trial because it is

not acted on by any outside forces, such as gravity.


Newton’s third law of motion states that forces always come in action-reaction

pairs. This law does not apply to the car in Trial 1 because there is no action

force on the car.


Although the velocity at a particular point in time as an object is falling is

dependent on the height from which it is dropped, the rate at which an object

falls is always equal to the acceleration due to gravity. However, the car in

Trial 1 is at rest and is not being acted on by gravity.


Newton’s second law of motion is used to calculate the force acting on an

object. Because the car in Trial 1 is not moving and no force is acting on the

object, this law does not apply here.



Grade 8




PLD 2 f Basic: Identify Newton’s Three Laws of Motion.

DOK 1

28. Which of these is one of Newton’s laws of motion? F. An object’s momentum is the product of its mass and velocity. G. A moving object will continue moving until a force acts upon it. H. The force of gravity is proportional to the inverse square of the distance. J. The rate at which an object falls depends on the height from which it is dropped.


This is a restatement of Newton’s first law of motion, which says that an

object will move at a constant velocity until acted upon by an unbalanced

force.


This statement is true and is used while determining velocities before and

after a collision; however, it is not one of Newton’s laws of motion.


Although this statement is true, it is not one of the three Newtonian laws.


This statement is not one of Newton’s laws of motion and is stated

incorrectly. Although the velocity at a particular point in time as an object is

falling depends on the height from which it is dropped, the rate at which an

object falls is always equal to the acceleration due to gravity.



Grade 8

Strand Life Science

Competency 3: Compare and contrast the structure and functions of the cell, levels of

organization of living things, basis of heredity, and adaptations that explain

variations in populations.

PLD 3 a Proficient: Analyze how adaptations to a particular environment can increase

an organism's survival and reproduction and relate organisms and

their ecological niches to evolutionary change and extinction.

DOK 3

29. A light-colored insect lives on trees in a forest. The bark of the trees appeared white

because of light-colored lichen that also lived on the tree. Disease destroyed the lichen. The tree bark is now dark-colored. How will this environmental change affect the number of light-colored insects?

A. The number of insects will decrease because, with the lichen gone, the insects will have

no other source of food. B. The number of insects will decrease because predators will see the light-colored insects

on the dark bark more easily. C. The number of insects will increase because, with the lichen gone, the insects will no

longer have to compete with the lichen for space. D. The number of insects will increase because the insect predators that also eat the

diseased lichen will become ill and decrease in number.




The light-colored lichen formed a covering that allowed the insects to be

camouflaged from predators. With the lichen gone, the insects will be easily

seen and preyed upon more often, decreasing the numbers in their

population.


There is no indication that the lichen was a food source for the insects.

Because the lichen forms a covering that allows the insects to be

camouflaged, it is more likely that this change will affect the insects’ ability to

hide from predators.


It is not likely that the insects were competing for space with the lichen.

Lichen form a covering that allows the insects to be camouflaged and

lessens predation.


It is not likely that the same predators that eat the insects will also eat the

lichen. Additionally, it cannot be assumed that a disease that affects lichen

will also affect organisms of a different species.



Grade 8

Strand Life Science




PLD 3 b Proficient: Compare and contrast the major components and functions of

different types of cells.

DOK 2

30. Chloroplasts are organelles that are found in plant cells. Some plant tissue contains

cells with large numbers of chloroplasts, while other tissue contains few chloroplasts. Which type of plant tissue contains cells with many chloroplasts?

F. Stem, because chloroplasts are needed for plant growth G. Root, because chloroplasts are needed for water uptake H. Leaf, because chloroplasts are needed for photosynthesis J. Flower, because chloroplasts are needed for reproduction


The role of chloroplasts is to create sugars through the process of

photosynthesis. This process relies on the absorption of sunlight. Because

the leaves are the part of a plant with the most exposure to direct sunlight,

the cells in this tissue contain the largest number of chloroplasts.


Some plant stems do contain chloroplasts. However, the majority of

chloroplasts are located in the leaves, which are structured to absorb light.

Additionally, chloroplasts do not play a direct role in plant growth.


Roots are necessary for water absorption, and chloroplasts need water to

make sugars. However, chloroplasts do not play a direct role in water

absorption.


Chloroplasts do not directly contribute to reproduction.



Grade 8

Strand Life Science




PLD 3 b Basic: Identify different cell types and their structures.

DOK 1

31. Chris viewed the following cell through a microscope lens.

Which type of cell is Chris observing? A. Nerve cell B. Bone cell C. Blood cell D. Muscle cell

Nucleus

Dendrite

Cell body

Axon




The dendrites and axons shown are specialized extensions that allow this

type of cell to carry impulses long distances. Because the role of nerve cells is

to transport messages between the brain and other parts of the body, the

extensive branching and structures shown support the function of a nerve cell.


The function of bone cells is to create new bone. Therefore, bone cells often

contain multiple nuclei as a result of cells fusing together.


The function of blood cells is to carry oxygenated blood throughout the body.

Because of this, blood cells are often small and do not contain a nucleus so

that they can hold as much hemoglobin as possible but can also squeeze

through small blood vessels.


The function of muscle cells is to allow movement. To do this, they must

create a large amount of energy. Therefore, muscle cells contain many

mitochondria. Additionally, they are usually packed together tightly to transfer

movements.



Grade 8

Strand Life Science




PLD 3 c Proficient: Describe how viruses, bacteria, fungi, and parasites may infect the

human body and interfere with normal body functions.

DOK 1

32. Which of these describes a pathogen that infects a human by injecting its DNA into a

body cell? F. A parasite that robs the cell of nutrients, interfering with organ functions G. A bacterium that creates a toxin that destroys the cell, keeping the cell from working in a

normal manner H. A fungus that eats keratin found in skin cells, causing inflammation and interfering with

the skin tissues’ ability to protect J. A virus that changes the way a cell works, causing the cell to make more viruses instead

of performing its intended function


Viruses interfere with cell functioning by injecting their DNA into host cells.

The virus takes over protein manufacture and produces viral proteins to

create more viruses because viruses cannot reproduce on their own.


Parasites do not inject DNA into body cells. Parasites live in or on the host,

robbing the host of nutrients.


Bacteria do not inject DNA into body cells. The toxins created by bacteria are

by-products of their metabolism and do not contain bacterial DNA.

Additionally, toxins are not injected into host cells but rather interfere with

normal functioning by being present in the human body.


Fungi do not inject DNA into body cells. Fungi eat substances found in host

cells, causing irritation and improper functioning of cells.



Grade 8

Strand Life Science




PLD 3 d Proficient: Describe heredity as the passage of instructions from one

generation to another and recognize that hereditary information is

contained in genes, located in the chromosomes of each cell.

DOK 2

33. Lisa notices that her pet rabbits have similar fur color to their parents. Lisa draws the following diagram to show how fur color passes from the parents to the offspring.

Which offspring description will complete the diagram? A. • Offspring receives two DNA strands from each parent.

• DNA strands contain chromosomes. • Chromosomes from Parent 1 determine appearance of fur.

B. • Offspring receives half of DNA strand from each parent.

• Each half of DNA strand connects to form chromosome. • One chromosome determines appearance of fur.

C. • Offspring receives a set of two chromosomes, one from each parent.

• Chromosomes contain DNA strands. • DNA strands contain genes. • A pair of genes determines appearance of fur.

D. • Offspring receives a set of two chromosomes, one from each parent.

• Chromosomes contain genes. • Genes contain DNA strands. • Two sets of DNA strands determine appearance of fur.

Offspring

?

Parent 1

Gene for fur color is locatedon DNA strand;

DNA is coiled into chromosomewithin a cell.

Parent 2

Gene for fur color is locatedon DNA strand;

DNA is coiled into chromosomewithin a cell.




Chromosomes are made up of coiled strands of DNA. Within the strands of

DNA, specific sequences compose genes. When the offspring receives a

chromosome from each parent, the pair of genes will determine the trait.


Offspring would not receive two DNA strands from each parent because

this would cause offspring to have twice the amount of genetic material as

is appropriate for the organism. Additionally, DNA makes up chromosomes

rather than containing them. Appearance of fur color is dictated by a pair of

genes located on each chromosome received from each parent.


Offspring receives a set of chromosomes, one from each parent. Each

chromosome is made up of coiled, double-helix-shaped DNA strands

containing specific sequences called genes. A pair of genes, one from each

chromosome, determines the appearance of fur.


Chromosomes are made up of coiled strands of DNA, and DNA strands

contain specific sequences called genes. When the offspring receives a

chromosome from each parent, the pair of genes located on the DNA

strands will determine the trait.



Grade 8

Strand Life Science




PLD 3 d Advanced: Analyze a pedigree diagram to predict the inheritance for a

particular trait for a family member.

DOK 3

34. Some people are unable to see red and green colors. This condition, colorblindness, is

a recessive trait carried on the X chromosome, Xb. The following pedigree shows a family in which some individuals are affected by colorblindness.

Family members 6 and 7 in Generation II are expecting a son. The father’s genotype is XBY, while the mother’s is XBXb, as shown in the Punnett square. Which of the following describes the possibility of this son being colorblind?

F. Zero percent, because the father is not colorblind

G. Twenty-five percent, because in the Punnett square, only one box out of four shows an affected male

H. Fifty percent, because only one of the two males in the Punnett square has the genotype for being affected

J. One hundred percent, because the mother will pass the colorblindness trait to all offspring through her X chromosome

Family Pedigree Showing Colorblindness Trait

1

I

II

III

2

1 2 3 4 5 6 7

1 2

XB

XB

Y

Xb

3

?

= unaffected male

= unaffected female

= affected male

= carrier female

Key

XBXB XBXb

XBY XbY




This takes gender into account and correctly interprets the meaning of the

recessive trait. Because the couple already knows they are having a son

and the Punnett square shows two possibilities for a son, the one box

showing an affected male represents 50% of the possibilities.


This would be the percentage if neither parent had the recessive gene. The

father is not colorblind and does not have the recessive gene. However, the

mother is a carrier. According to the Punnett square, there is a 50% chance

that the couple will have a son who is colorblind.


This would be the percentage if the gender was not specified. Because the

couple already knows they are having a son and the Punnett square shows

two possibilities for a son, the one box showing an affected male

represents 50% of the possibilities.


This would be the percentage if the mother were colorblind and had two

recessive genes. Because the mother is a carrier, she has a 50% chance

that she will pass on the recessive gene to a child. According to the

Punnett square, there is a 50% chance that the couple will have a son who

is colorblind.



Grade 8

Strand Life Science




PLD 3 e Proficient: Explain energy flow in a specified ecosystem.

DOK 2

35. The following diagram shows an energy pyramid for a wetland in Mississippi.

Which conclusion is supported by this diagram? A. River otters are tertiary consumers and have the least energy available to them. B. Crayfish are secondary consumers and have the most energy available to them. C. Phytoplankton are primary producers and have the least energy available to them. D. Zooplankton are secondary producers and have the most energy available to them.

Energy Pyramid of Mississippi Wetland

Phytoplankton

Zooplankton

Crayfish

River Otter




Because river otters get energy from an organism that consumes

herbivores, they are considered tertiary consumers. Additionally, as energy

flows from producer to the top consumer, energy is lost at each step. In this

pyramid, river otters are the last consumers listed and therefore have the

least amount of energy available to them.


Because crayfish get energy from herbivores (organisms that consume only

producers), they are considered secondary consumers. However, energy

decreases as it flows from organism to organism in the food chain, so

crayfish have less energy available to them than zooplankton and

phytoplankton.


Because phytoplankton make their own energy from the sun and are

autotrophic, they are considered primary producers. However, they have

the most energy available to them because energy decreases as it flows

from organism to organism in the food chain, and phytoplankton do not

receive energy from another organism.


Because zooplankton get energy from producers (phytoplankton) and do

not create their own energy from the sun, they are considered primary

consumers rather than secondary producers. Additionally, as energy flows

from organism to organism in the food chain, energy is lost. Because

zooplankton receive energy from another organism, they do not have the

most energy available to them.



Grade 8

Strand Life Science




PLD 3 e Advanced: Analyze the food web of an ecosystem in which the population of

an organism has been altered to explain how this change may

affect another member of the food web ecosystem.

DOK 3

36. The following diagram shows a food web for a large lake.

The number of trout in the lake decreased due to overfishing by humans. Which statement describes the impact of this change on the other organisms in the food web?

F. The number of forage fish will decrease since they will have fewer trout upon which to prey.

G. The number of plankton will increase since fewer organisms will be getting energy from them.

H. The eagles will lose a source of energy and need to get energy from gulls, forage fish, and snapping turtles.

J. The snapping turtles will lose a source of energy and will need to get energy from gulls, eagles, and waterfowl.

Lake Food Web

Eagle Human

Trout

Gull

Forage Fish Waterfowl

SnappingTurtle

Vegetation

Plankton

Decaying Plant Material

Bacteriaand Fungi

Invertebrates




Eagles receive energy from gulls, forage fish, trout, and snapping turtles. A

decrease in the trout population would not cause much of a change in the

eagle population because these organisms will switch to receiving energy

from their other remaining sources.


The forage fish population would increase rather than decrease because

trout are consumers of forage fish, so there would be fewer organisms that

prey upon them.


The plankton population would decrease rather than increase because the

change would lead to an increase in the forage fish population. Because

forage fish consume plankton, there would be more organisms getting their

energy from plankton.


Snapping turtles do not consume larger, predatory fish such as trout. From

the diagram, snapping turtles receive their energy from forage fish only, so

they will not need to change their food source.



Grade 8

Strand Life Science




PLD 3 f Proficient: Develop a logical argument for or against research conducted in

selective breeding and genetic engineering, including research

conducted in Mississippi.

DOK 3

37. A bacterium, Bacillus thuringiensis (Bt), makes a toxin that destroys the larvae of

insects that threaten corn crops. Scientists engineered corn plants, known as Bt-corn. Bt-corn can make a toxin to destroy the larvae that eat the corn. Which of these supports the argument to stop production of genetically engineered Bt-corn?

A. Bt-corn pollen may harm helpful insects that pollinate the corn, such as bees. B. Bt-corn kernels may attract unwanted animals that can damage the crop, such as crows. C. Bt-corn plants use much less pesticide than unmodified corn plants. D. Bt-corn seed is more expensive than unmodified corn seed.




If the toxin created by Bt-corn is toxic to insect larvae, it can be assumed that

it may also be harmful to full-grown insects. Although some insects may be

detrimental to plant growth, there are many that are essential to the plants’

reproduction cycle, such as bees. Harming these insects is a logical concern

that could support stopping the production of Bt-corn.


There is no evidence in the scenario given to support this concern. The toxin

produced by Bt-corn is said to be harmful to insect larvae, but it cannot be

assumed that it would have an effect on other animals.


Using less pesticide due to the use of the genetically modified corn would be

beneficial to the environment. If true, this concern would provide support for

continuing to produce Bt-corn rather than stopping it.


An increase in seed price may be offset by a reduction in other costs, such

as pesticide and the fuel to apply it to the fields. The net result may actually

be that modified seed is less expensive overall.



Grade 8

Strand Life Science




PLD 3 f Basic: Identify examples of selective breeding or genetic engineering.

DOK 1

38. Which activity is an example of selective breeding? F. Collecting wild saplings from a forest and replanting them G. Cross-pollinating plants that produce large numbers of fruit H. Allowing a population of laboratory mice to mate randomly J. Raising sheep that have been cloned from adult sheep tissues


Cross-pollinating involves selecting parents with the genes for desired traits

and breeding, through pollination. The desired trait, producing large numbers

of fruit, will be exhibited by the offspring as a result of this selective breeding.


This activity describes altering the habitat of an organism but does not

involve breeding. For a process to be considered selective breeding, two

parents with particular genes must be intentionally bred to produce the

desired trait.


This activity involves the process of sexual reproduction as it occurs

naturally, without selection by humans. For a process to be considered

selective breeding, two parents with particular genes must be intentionally

bred to produce the desired trait.


This activity describes the process of cloning, which involves producing

genetically identical offspring from one parent. For a process to be

considered selective breeding, two parents with particular genes must be

intentionally bred to produce the desired trait.



Grade 8

Strand Life Science




PLD 3 g Proficient: Research and draw conclusions about the use of single-celled

organisms in industry and in the production of food and about their

impact on life.

DOK 3

39. Bacteria on the roots of soybean plants are able to change nitrogen from the air into a

form usable by plants. Scientists have engineered other plants to support the growth of these nitrogen-fixing bacteria. Which of these describes a benefit of this research?

A. The need for space will decrease, allowing more land to be available for other crops. B. The need for water will decrease, allowing more water to be available for other crops. C. The need for fertilizer will decrease, reducing both the amount of fertilizer runoff and the

algae growth in streams and ponds. D. The need for pesticides will decrease, reducing both the amount of chemicals applied to

crops and the pollution of the water table.




This is a logical inference based on the information given. Fertilizers help

optimize plant growth by providing essential nutrients. Because the plants

would be better able to obtain some of these nutrients on their own, the need

for fertilizer would most likely decrease. This would be beneficial for the

environment because it would reduce the harmful effects caused by the

chemicals in fertilizer.


This response does not provide a logical inference based on the information

given. If soybean plants are better able to use the nitrogen from the air, it

would be expected that an increase, rather than a decrease, in plant growth

would occur due to the increase in available nutrients.


This response does not make a logical inference based on the information

given. An increase in the ability of soybean plants to use nitrogen from the air

would not necessarily mean they would have less of a need for other

essential nutrients such as water.


The response does not provide a logical inference based on the information

given. The use of pesticides does not contribute to nitrogen fixation and

would therefore not be affected by this type of genetic engineering.



Grade 8

Strand Life Science




PLD 3 g Basic: Identify examples of single-celled organisms that are used in

industry or food production or that impact life.

DOK 1

40. Which statement describes how a single-celled organism helps make a food product? F. Viruses that cause diseases are weakened and used to make vaccines. G. Yeast changes carbohydrates into carbon dioxide to make dough rise. H. Fungi release a chemical that keeps bacteria colonies from growing larger. J. Bacteria eat oil spilled in rivers and change it into less dangerous compounds.


This response describes both a single-celled organism and its use in food

production.


Although it is true that viruses can be used in this manner, this answer choice

does not describe a food product. Additionally, viruses are not considered to

be living and are therefore not single-celled organisms.


This process may be beneficial in medicine, but the response does not show

how it would be used to help make a food product.


Although bacteria are single-celled organisms, this response does not describe

how they would be used to make a food product.



Grade 8

Strand Life Science




PLD 3 h Proficient: Describe how an organism gets energy from oxidizing its food and

releasing some of its energy as heat.

DOK 1

41. Food is digested and then delivered to body cells.

Which of these describes how the cells respond?

A. The cells absorb the energy in food through photosynthesis. B. The cells convert the food into nutrients through fermentation. C. The cells use the food and oxygen to make energy and release heat. D. The cells use the food to make heat energy through anaerobic respiration.


Organisms get energy by oxidizing food. This process is carried out in body

cells and is called cellular respiration. During cellular respiration, sugar in the

food is broken down using oxygen, and carbon dioxide, water, and energy are

produced. The excess energy produced is then released by the cell as heat.


Photosynthesis is the process in which plants create food using energy from

the sun. Plant cells then use the process of cellular respiration to release the

energy in the food.


Fermentation is the process in which sugar in food is broken down in the

absence of oxygen to produce some energy and waste products, not

nutrients.


Anaerobic respiration is the process in which sugar in food is broken down in

the absence of oxygen to produce some energy and waste products.



Grade 8

Strand Life Science




PLD 3 h Advanced: Explain the process of cellular respiration to the survival of the cell

and its components.

DOK 3

42. Which of these describes how the absence of mitochondria would affect a cell? F. Heat would build up and cause the cell to become dehydrated because mitochondria

release energy. G. Toxins would collect and slow the production of ATP because mitochondria remove

waste from cells. H. Cells would be unable to undergo cellular respiration because mitochondria convert

glucose into energy. J. Cells would be unable to undergo fermentation because mitochondria convert

carbohydrates into sugars.


Mitochondria are the part of the cell in which cellular respiration occurs. This

is the process by which the cell converts glucose, or sugar, into energy.

Without mitochondria, the cell would lack the energy necessary to perform

vital functions.


Mitochondria produce energy for the cell. Without them, the cell would lack

the energy necessary to perform functions essential to survival. Heat is

released when there is excess energy produced. This would not occur if there

was no energy being produced.


Mitochondria do not remove waste from cells. Rather, they produce energy.

Without mitochondria, the cell would not be able to produce ATP and would

therefore not be able to perform functions essential to survival.


Mitochondria do not convert carbohydrates into sugars. They convert sugar

into energy through cellular respiration. Without mitochondria, the cell would

lack the energy necessary to perform essential life functions.



Grade 8

Strand Life Science




PLD 3 h Basic: Identify the reactants and products involved in cellular respiration.

DOK 1

Bandaging Bacteria

















PetriDish


1

2

3

4

Staphylococcus

Pseudomonas

E. Coli







43. What are the reactants and the products of cellular respiration in the harmful

bacteria? A. Reactants: oxygen, glucose from human cells

Products: water, carbon dioxide, energy B. Reactants: glucose, water from human cells

Products: oxygen, energy, carbon dioxide C. Reactants: energy from human cells, nitrogen

Products: glucose, water, oxygen D. Reactants: nitrogen, glucose from human cells

Products: water, oxygen, carbon dioxide


During cellular respiration, the cell uses oxygen and glucose to produce

energy. The waste products, carbon dioxide and water, are also obtained

through this process.


During cellular respiration, cells use oxygen to break down glucose and

produce energy, carbon dioxide, and water. This response switches water

and oxygen in the reactants and products.



produce energy, carbon dioxide, and water. Nitrogen is not involved in this

process.



produce energy, carbon dioxide, and water. Nitrogen is not involved in this

process.



Grade 8

Strand Earth and Space Science

Competency 4: Describe the Earth’s System in terms of its position to objects in the

universe, structure and composition, climate, and renewable and

nonrenewable resources.

PLD 4 a Proficient: Compare and contrast the lithosphere and the asthenosphere.

DOK 1

44. Which of these describes the lithosphere and the asthenosphere? F. The lithosphere is rigid and immovable, and the asthenosphere is hot and flowing. G. The asthenosphere is rigid and immovable, and the lithosphere is hot and flowing. H. Both are hot inner layers of earth capable of bending and moving. J. Both are hard and rigid layers of earth close to the surface.


The lithosphere is brittle and rigid and does not move freely. If internal

Earth forces cause motion, the lithospheric plates will rub, collide, or

diverge. The asthenosphere is much hotter than the lithosphere, allowing

the rock in the asthenosphere to flow and change shape easily.


The asthenosphere is hot and flowing, and the lithosphere is rigid and

immovable.


The lithosphere and the asthenosphere are located in the upper layer of

Earth, not the inner layers. The asthenosphere is able to bend and move,

but the lithosphere is rigid and does not move easily.


The lithosphere and the asthenosphere are located in the upper layer of

Earth, but only the lithosphere is rigid. The asthenosphere is plastic and

flowing.



Grade 8





PLD 4 a Advanced: Explain how the composition of the lithosphere and

asthenosphere affects plate movement.

DOK 2

45. Which of these describes a cause of lithospheric plate movement across the

surface of Earth? A. The plates are driven by bubbles from the boiling liquid of the asthenosphere. B. The plates float on dense liquid material of the asthenosphere and are moved by tidal

forces. C. The plates are driven across the surface by convection currents within the plastic

rock of the asthenosphere. D. The plates move because they are attached to the solid rock of the asthenosphere

and move with that rock.


The asthenosphere is composed of rock that is partially melted. This

causes the asthenosphere to take on plastic-like properties. The

asthenosphere is not as hot as the lower mantle below it, so uneven

heating occurs, causing warmer areas within the asthenosphere to rise and

cooler areas to sink. This creates convection currents that cause plate

movement.


The asthenosphere is part of the upper mantle, which is not as hot as the

lower mantle. Thus, uneven heating causes rising of warmer areas and

sinking of cooler areas, producing convection currents. These currents are

similar to the effect of boiling. However, the asthenosphere is not boiling

because it is only partially liquefied.




The asthenosphere is not completely liquefied. Rather, it is plastic-like and

flowing. The uneven heating of this plastic, flowing layer creates convection

currents, rather than tidal forces, that cause lithospheric plate movement.


The asthenosphere is not a solid rock. It is a plastic-like, flowing layer on

which the solid lithospheric plates float but are not attached. Convection

currents within the asthenosphere cause plate movement.



Grade 8





PLD 4 a Basic: Identify the composition, physical nature, or location of the

lithosphere or the asthenosphere.

DOK 1

46. Which of these describes the lithosphere? F. Topmost solid part of Earth in which crust is located G. Middle liquid, flowing layer of Earth on which crust floats H. Middle plastic, flowing layer of Earth on which the asthenosphere floats J. Topmost semisolid part of Earth in which magma chambers for volcanoes form


This response describes the lithosphere accurately as consisting of the

rigid, topmost part of the mantle and all of the crust.


This is a description of the asthenosphere, which is the hot, plastic-like

layer just under the lithosphere and is still part of the upper mantle.


This is a combination of the definitions of the lithosphere and the

asthenosphere. The lithosphere floats on the asthenosphere, but the

asthenosphere is the middle, plastic, flowing layer.


Magma chambers may be located in the lithosphere, but this layer is

completely solid and rigid.



Grade 8





PLD 4 b Proficient: Describe the cause and effect relationship between the

composition of and movement within the Earth’s lithosphere.

DOK 1

47. About 30 miles into Earth, the speed of seismic waves increases.

What does this change in speed indicate about the material through which the seismic waves are traveling?

A. The waves travel from rock into metal material. B. The waves travel from cool material into hot material. C. The waves travel from solid material into liquid material. D. The waves travel from a less dense material into a more dense material.


The factor that has the greatest influence over seismic wave speed in the

lithosphere is the composition of the material through which it is traveling.

Since waves travel faster in more dense materials, they must be traveling

from less to more dense material in this situation.


The lithosphere is not composed of metal. Rather, it is the rigid top layer of

Earth, composed of cool rock.


The factor that has the greatest influence over seismic wave speed in the

lithosphere is the composition of the material through which it is traveling.

Additionally, it is not likely that the waves are traveling from cool to hot

material because the lithosphere is composed of cooled rock at the surface

of Earth.


The lithosphere is composed of solid, rigid rock. Since it is the cool, upper

layer of Earth, there is no liquid material present here.



Grade 8





PLD 4 b Advanced: Predict geologic phenomena based on the composition and

movement of interacting plates.

DOK 3

48. The following diagram shows the motion of two plates.

Which of these explains the feature that can form at the boundary of these two

plates? F. A broad canyon-like valley because the two colliding plates act like a plow, digging out

any soil in the plates’ paths. G. Volcanic mountain range because one oceanic plate melts underneath the continental

plate, forming composite volcanoes on the continent H. Island arc because one oceanic plate melts underneath the continental plate, forming

volcanic mountains that eventually become islands J. Folded mountain range because the two colliding plates have equal composition and

density, causing both to fold and form wide, thick mountains.

ContinentalCrust

OceanicCrust




Oceanic plates are more dense than continental plates. The more dense

oceanic plate will subduct under the less dense continental plate. The

mantle above the subducting plate melts and is pushed up toward the

surface of Earth, forming volcanic mountains.


The collision of the plates occurs at a boundary below the crust and cannot

be seen from the surface of Earth.


The collision of two oceanic plates creates an island arc. The collision

between an oceanic plate and a continental plate leads to volcano

formation on the continental crust rather than the oceanic crust because

the more dense oceanic plate subducts under the less dense continental

plate.


Oceanic plates are more dense than continental plates. The more dense

oceanic plate will subduct, rather than fold, under the less dense

continental plate, forming volcanic mountains.



Grade 8





PLD 4 b Basic: Identify plate boundaries based on lithospheric movement.

DOK 1

49. Which of these describes a divergent boundary? A. Two continental plates moving away from each other, forming a rift valley B. Two oceanic plates rubbing against each other, forming a midocean ridge C. Two continental plates colliding, forming a mountain range D. Two oceanic plates colliding, forming a volcanic arc


A divergent boundary is established where two plates are moving away

from each other. When this happens on land between two continental

plates, a rift valley forms.


A divergent boundary between two oceanic plates would result in a mid-

ocean ridge. This answer response refers to plates that are rubbing against

each other, and that would instead establish a transform boundary.


A divergent boundary between two continental plates would result in a rift

valley, not a mountain range. This response refers to plates that are

colliding, which would instead establish a convergent boundary.


A divergent boundary between two oceanic plates would result in a mid-

ocean ridge, not a volcanic arc. This response refers to plates that are

colliding, which would instead establish a convergent boundary.



Grade 8





PLD 4 c Proficient: Examine weather forecasting and describe how meteorologists

use atmospheric features and technology to predict the weather.

DOK 2

50. Early in the afternoon, a weather station outside the school shows that the

barometric pressure and temperature are both dropping rapidly. What type of weather do these readings indicate?

F. Several days of clear, sunny weather G. Cool, cloudy weather with little chance of rain H. Thunderstorms later in the afternoon or evening J. Clearing weather today with rain likely tomorrow


Rapidly dropping temperature and pressure are indications that a front is

quickly approaching, bringing heavy rain and thunderstorms.


Clear, sunny weather would be expected after a cold front has passed and

during the presence of a high-pressure system. Rapidly dropping

temperature and pressure indicate that the front is approaching and has not

yet passed.


Cool, cloudy weather with little chance of rain would be expected as a cold

front passes through an area with warm, dry weather. Because the

temperature and pressure are rapidly decreasing, a cold front is most likely

approaching an area with warm, moist air, bringing heavy rain and

thunderstorms.


Rapidly dropping temperature and pressure are an indication that a front is

quickly approaching. This would lead to rain and thunderstorms, followed

by clearing weather the next day.



Grade 8





PLD 4 c Advanced: Predict a change in weather based on differences in pressure,

heat, air movement, and humidity.

DOK 3

51. A meteorologist is monitoring the weather around Capital City. She collects the

following data from her weather instruments: • Air pressure dropping quickly • Warm air rising rapidly • Water droplets being pushed upward to the topmost part of a cumulonimbus

cloud • Doppler radar map shows pockets of air with the wind blowing in opposite

directions Based on the weather data, what should the meteorologist include in the weather forecast for the Capital City area?

A. Increasing humidity with light rain B. Drop in air temperature with light snow C. Tornado watch with heavy rain and hail D. Approaching hurricane with heavy rain and strong winds


The data collected indicate that the conditions are right for a severe

thunderstorm with the potential to create tornadoes. Air pressure dropping

quickly and warm air rising indicate that a cold front is quickly approaching

and forcing the warm, moist air at the surface to rise. The presence of a

cumulonimbus cloud and water droplets being pushed upward are signs of

a strong updraft that could cause tilt and rotation. Wind blowing in opposite

directions on the radar map also indicates wind shear and the possibility for

rotation within the thunderstorm, which could lead to a tornado.





thunderstorm with the potential to create tornadoes. This is the result of a

cold front approaching an area of warm, moist air. Increasing humidity and

light rain would be indicated by a warm front approaching rather than a cold

front.



thunderstorm with the potential to create tornadoes. This is the result of a

cold front approaching an area of warm, moist air. Light snow would be

indicated by a warm front approaching and air temperatures below freezing

throughout the atmosphere. The presence of warm air rising rapidly

indicates that this is not what is happening.


The data collected indicate that a quick-moving system is approaching. The

rapidly rising warm air and wind blowing in opposite directions mean that

the system is forming. An approaching hurricane would create strong winds

and heavy rains, like a thunderstorm, but development would not occur

over land because hurricanes develop over warm ocean water.



Grade 8





PLD 4 d Proficient: Research the importance of the conservation of renewable and

nonrenewable resources, including Mississippi, and justify

methods that might be useful in decreasing the human impact

on global warming.

DOK 3

52. Deforestation is the removal of naturally occurring forests. These forests are

cleared in order to provide land for farms or buildings. Some scientists want to reduce the amount of deforestation. How would reducing deforestation affect global warming?

F. It would prevent farmers from planting renewable biofuels that would have reduced

global warming. G. It would decrease the amount of carbon dioxide reaching the atmosphere, reducing

global warming.

H. It would increase the amount of oxygen released into the atmosphere, which would

bond together and create ozone, increasing global warming. J. It would prevent destruction of animal homes, allowing these animals to survive and

breathe in oxygen that would otherwise increase global warming.


Reducing deforestation would decrease the amount of carbon dioxide in

the atmosphere because fewer trees would be cut down, and trees use

carbon dioxide during photosynthesis. Reduction in the amount of carbon

dioxide in the atmosphere decreases global warming.


Since trees use carbon dioxide during photosynthesis, reducing

deforestation would likely decrease the amount of carbon dioxide in the

atmosphere and decrease global warming. Additionally, the information

given refers to using the land for farms and buildings, and the types of

farms are not indicated. Therefore, forests removed through deforestation

are not necessarily replaced by renewable biofuels.




A decrease in the amount of carbon dioxide due to a decrease in

deforestation would actually lead to a decrease in global warming.

Increasing the amount of oxygen in the atmosphere and the creation of

ozone would not increase global warming.


A decrease in carbon dioxide in the atmosphere because of an increase in

the number of trees using it during photosynthesis would cause a decrease

in global warming. Reducing deforestation could prevent destruction of

animal homes, which would benefit the environment but does not affect

global warming.



Grade 8





PLD 4 d Basic: Identify renewable or nonrenewable resources.

DOK 1

53. Which of these is a renewable energy resource that does not produce carbon

dioxide? A. Coal B. Wind C. Biomass D. Fossil fuel


Wind is a renewable resource because it can be used to produce energy

over and over again. The use of wind as an energy source does not involve

burning, so it does not produce carbon dioxide.


Coal is a nonrenewable resource because it exists in limited amounts on

Earth. It takes millions of years for decayed plants to turn into coal. As it

burns, coal produces carbon dioxide.


Biomass is renewable but produces carbon dioxide as it burns.


Fossil fuels are nonrenewable resources because they exist in limited

amounts on Earth. Burning of fossil fuels produces carbon dioxide.



Grade 8





PLD 4 e Proficient: Explain how the tilt of Earth’s axis and the position of the Earth

in relation to the sun determine climatic zones, season, and

length of the days.

DOK 2

54. At a certain time of year, the Southern Hemisphere is tilted toward the sun.

Which of these describes how this tilt affects the Southern Hemisphere during this time of year?

F. The days will be longer in the Southern Hemisphere during this time of year. G. The nights will be longer in the Southern Hemisphere during this time of year.

H. The seasons will be longer in the Southern Hemisphere during this time of year. J. The sun will rise lower in the sky in the Southern Hemisphere during this time of year.


The hemisphere of Earth that is tilted toward the sun receives more direct

sunlight and experiences the summer season. During the summer season,

the summer solstice occurs, which is the day that the sun reaches the

highest point in the sky and is the longest day of the year for that

hemisphere. Thus, the days are longer for the Southern Hemisphere when

it is tilted toward the sun.


The nights will be longer in the Southern Hemisphere during the winter.

This corresponds to the summer for the Northern Hemisphere. During its

winter season, the Southern Hemisphere is tilted away from the sun rather

than toward the sun.




During the time of year when the Southern Hemisphere is tilted toward the

sun, this hemisphere will experience summer and longer days. The

seasons occur because of the tilt of Earth, but the length of seasons is not

changed.


The hemisphere of Earth that is tilted toward the sun receives more direct

sunlight and experiences longer days. During the summer season, the days

are longer because the sun reaches the highest point in the sky on the

summer solstice.



Grade 8





PLD 4 e Advanced: Explain how a change in the angle of Earth’s axis affects climate

and seasons.

DOK 3

55. The following diagrams show the axis of Earth at its present 23° angle and at a

perpendicular axis of 0°.

How would seasons be affected if Earth’s axis were at a 0° angle? A. Earth would have no seasons. B. Seasonal variation would decrease at the poles. C. Seasonal variation would increase at the equator. D. Earth would have two seasons instead of four seasons.


The tilt of Earth’s axis is what causes the seasons on Earth. If the tilt were

0°, Earth would not be tilted and no seasons would occur.


Seasonal variation would decrease at the poles because the poles would

no longer be angled toward or away from the sun. Indirect sunlight would

be equally distributed at each pole.


Seasonal variation would decrease at the equator because the equator

would no longer be angled toward or away from the sun. Direct sunlight

would be equally distributed at each pole.


The tilt of Earth’s axis is what causes the seasons on Earth. If the tilt were

0°, all parts of Earth would receive the same amount of sunlight during all

parts of the year. Earth would not experience any seasonal variation.

Earth with Axisat 23º Angle

Earth with Axisat 0º Angle



Grade 8





PLD 4 e Basic: Identify the effect of Earth’s tilt on its axis or the position of Earth in

relation to the Sun on seasons and climate.

DOK 1

56. During which season does sunlight strike the Northern Hemisphere as shown?

F. Spring G. Summer H. Fall J. Winter


When Earth tilts on its axis so that the Northern Hemisphere is toward the

sun, the Northern Hemisphere experiences summer. It is the time of the

year when the Northern Hemisphere receives the greatest amount of direct

sunlight.


On the first day of spring in the Northern Hemisphere, Earth’s tilt is neither

toward nor away from the sun. Earth is at an equinox, meaning that the

Northern and Southern Hemispheres receive equal amounts of direct

sunlight on that day.

SunlightEarth

N




On the first day of fall in the Northern Hemisphere, Earth’s tilt is neither

toward nor away from the sun. Earth is at an equinox, meaning that the

Northern and Southern Hemispheres receive equal amounts of direct

sunlight on that day.


When Earth tilts on its axis so that the Northern Hemisphere is away from

the Sun, the Northern Hemisphere experiences winter. It is the time of the

year when the Northern Hemisphere receives the least amount of direct

sunlight.



Grade 8





PLD 4 f Proficient: Describe the hierarchical structure (stars, clusters, galaxies,

galactic clusters) of the universe and examine the expanding

universe to include its age and history and the modern

techniques used to measure objects and distances in the

universe.

DOK 2

57. Astronomers often try to find the hottest stars in our galaxy.

Which wavelength of radiation do astronomers use to detect these hottest stars?

A. Infrared B. Ultraviolet C. Visible D. X-ray


Astronomers use detectors to study certain wavelengths of light. The

hottest stars in our galaxy emit mostly ultraviolet wavelengths of light.

Cooler stars emit most of their light in lower-energy regions of the

electromagnetic spectrum, rather than in the ultraviolet region. It is easiest

to spot hot stars using ultraviolet light because they emit the most light in

this region.


Astronomers use detectors to study certain wavelengths of light. Cooler,

lower-energy stars generally emit most light in the infrared part of the

spectrum. Since dust clouds in space do not absorb infrared wavelengths,

these are used to study cooler stars that have low energy and are hidden

by dust clouds.




Visible wavelengths of light are emitted by most stars, regardless of

temperature. Therefore, using visible light would not help astronomers to

distinguish the hottest stars from cooler stars.


X-rays are not generally emitted by stars. Although hot stars emit some

energy in the x-ray region, they emit mostly ultraviolet light. Cosmic

explosions, such as supernovas and black holes, are generally studied

using x-ray radiation.



Grade 8





PLD 4 f Advanced: Explain techniques used to determine distances between

objects in the universe or used to determine the age of the

universe.

DOK 3

58. What can scientists conclude about a galaxy whose light is shifted toward shorter

wavelengths? F. The galaxy is very distant and is moving away from Earth very rapidly. G. The galaxy is orbiting the center of the Milky Way at a very high speed.

H. The galaxy is expanding so rapidly that it appears to be moving toward Earth. J. The galaxy is relatively close since a distant galaxy's light is shifted toward longer

wavelengths.


Each galaxy emits light that is displayed as visible colors on the

electromagnetic spectrum. A galaxy moving farther away from Earth has an

increase in electromagnetic wavelength. This longer wavelength is

displayed as a shift to the redder portion of the electromagnetic spectrum.

A galaxy that is closer to Earth has a shorter wavelength that has very little

red shift on the electromagnetic spectrum.


Distant galaxies emit light that is shifted toward longer wavelengths on the

electromagnetic spectrum. The speed at which a galaxy moves toward or

away from Earth is determined by how much the light is shifted. A shorter

wavelength demonstrates the galaxy is relatively close.




A galaxy in the center of our Milky Way galaxy would emit light that is

shifted to the shorter-wavelength portion of the electromagnetic spectrum.

However, a galaxy is composed of billions of stars and therefore would not

orbit the center of another galaxy.


Because Earth is not the center of the universe, it is possible that a galaxy

is moving in an outward direction toward the Milky Way galaxy. However,

the galaxy in the question emits light that is shifted toward shorter

wavelengths of an electromagnetic spectrum. This indicates the galaxy is

close to Earth and therefore is moving at a constant rate similar to that of

the Milky Way galaxy and not expanding rapidly.



Grade 8





PLD 4 g Proficient: Justify the importance of continued research and use of new

technology in the development and commercialization of

potentially useful natural products, including, but not limited to,

research efforts in Mississippi.

DOK 3

59. The raising of catfish is a major industry in Mississippi. Catfish farmers in

Mississippi want scientists to research diseases affecting catfish. The following list describes the farmers’ reasons for wanting catfish diseases researched: 1) Understanding catfish diseases may lead to preventing these diseases. 2) Researching catfish diseases may help prevent diseases in other fish. 3) Curing catfish diseases may allow catfish farmers to raise more, healthier fish. 4) Studying catfish diseases may create catfish medications that the farmers could

sell to earn a profit. Which reasons from the list are logical justifications for researching catfish diseases?

A. 1 and 4 only B. 2 and 3 only C. 1, 2, and 3 only D. 2, 3, and 4 only




Statements 1, 2, and 3 all provide logical justifications for researching

disease. Prevention of disease in catfish as well as other fish and raising

healthier fish will have positive effects on the catfish industry in Mississippi.


Statement 1 provides logical justification for continuing this research, but

statement 4 does not. Preventing disease will have a positive effect on the

catfish industry. However, the profit earned by selling catfish medication will

directly benefit only the individual farmers who are selling the product rather

than the entire industry.


Statements 2 and 3 both provide logical justification for continuing this

research, but statement 1 also provides a logical justification. Prevention of

disease in catfish as well as other fish and raising healthier fish will have

positive effects on the catfish industry in Mississippi.


Statements 2 and 3 both provide logical justification for continuing this

research, but statement 4 does not. Prevention of disease in catfish as well

as other fish and raising healthier fish will have positive effects on the

catfish industry in Mississippi. However, the profit earned by selling catfish

medication will directly benefit only the individual farmers who are selling

the product rather than the entire industry.



Grade 8





PLD 4 h Proficient: Justify why an imaginary hurricane might or might not hit a

particular area, using important technological resources.

DOK 2

60. The following map shows the location of a hurricane in the Gulf of Mexico at 81° W

and 17° N.

Which of these describes the likely outcome for this hurricane?

F. The rotation of Earth will force the hurricane to the southeast, where it will make landfall.

G. The dry land surrounding the hurricane will absorb moisture from the hurricane, causing it to break apart.

H. Strong trade winds will blow the hurricane across the Yucatan Peninsula toward Mexico, where it will make landfall.

J. Strong ocean currents moving from the equator to the north will push the hurricane into Cuba, where it will break apart into many smaller storms.

Hurricane in the Gulf of Mexico

5 hurricane

5 high pressure

Key

1008 W 958 W 908 W 858 W 808 W 758 W

108 N

158 N

208 N

258 N

308 N

358 N

Gulfof

Mexico

MexicoYucatan

Peninsula

Cuba

N

S

EW

H

H




The trade winds between the equator and 30°N latitude blow from east to

west. These winds are the most influential factor in hurricane movement at

these latitudes. Since the hurricane is at 17°N latitude, the trade winds will

force it to move toward the Yucatan Peninsula, which is to the west.


Global winds are the most influential factor in guiding hurricane movement.

The rotation of Earth will not force the hurricane to move in a path opposite

to the prevailing winds at this latitude.


The hurricane has not yet made landfall and is still able to absorb moisture

from the warm ocean surrounding it. It will first be influenced by the trade

winds blowing east to west and will then make landfall and break apart as it

moves across the Yucatan Peninsula.


Global winds are the most influential factor in guiding hurricane movement.

Even though ocean currents may move toward the northeast, the prevailing

winds at this latitude will push the hurricane to the west, toward the

Yucatan Peninsula.

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