i. determining a purpose a.an experiment is a.an experiment is an organized procedure to study...
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I. Determining a PurposeI. Determining a Purpose
a.a. An experiment is An experiment is an organized procedure to study something under controlled conditions.
b.b. Write the purpose of your experiment as a Write the purpose of your experiment as a question or problem you want to investigate
To design an experiment, you need a purpose for the experiment.The purpose is the question you wish to investigate. The question should be written so that it cannot be answered with a “yes” or a “no”.
Question::
Observation::
You notice that the rocks in the middle of the river have rounded edges. On the edge of the river, the rocks have sharper edges.
Why are the rocks in the middle of the river more roundedthan those on the edges?
Question::
Observation::
You put a plant on a windowsill. After a few weeks, you notice that the leaves have all turned toward the window.
Why do the leaves of a plant turn toward the window?
You notice that when you eat chocolate ice cream at night, you have trouble falling asleep.
Observation::
Question::
Is there something in chocolate ice cream that keeps me awake at night?
Question:
Does increasing the air in a basketball make it bounce higher?
Prediction::
Increasing the air in a basketball will/will not make it bounce higher.
Observation #1
You observe when playing basketball that sometimes the ball bounces higher. Later, while filling the basketballs with air you notice that the amount of air in the basketballs can be different.
Question:
Prediction:
While watching your brother play with his toy cars, you notice when he rolls them down a ramp that they travel different distances. You wonder if the height of the ramp has any affect on how far the cars travel.
Will increasing the height of a ramp cause a car to travel farther?
Cars on higher ramps will/will not travel farther.
Observation #2
1. Will soaking seeds in water affect sprouting time?
Question:
Question:
Question:
Prediction:
Prediction:
Prediction:
Seeds soaked in water will sprout faster.
2. Will freezing popcorn affect the amount of kernels that pop?Freezing popcorn will cause more kernels to
pop.
3. Will increasing the temperature of water affect the amount of time it takes sugar to dissolve?
Increasing the temperature of water will cause sugar to dissolve
faster.Packet p.3Packet p.3
4. Does the temperature at which bread is stored affect mold growth?
Question:
Question:
Prediction:
Prediction:
Storing bread at cooler temperatures will cause mold to grow more slowly.
5. Does water temperature affect the time it takes water to freeze?
Increasing water temperature will cause water to freeze more quickly.
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II. Writing a Hypothesis
a.a. A hypothesis is A hypothesis is a tentative explanation for an observation or scientific problem that can be tested by further investigation.
b.b. A hypothesis is written in the form of an A hypothesis is written in the form of an if/then statement.statement.
Question:
Does increasing the air in a basketball make it bounce higher?
You observe when playing basketball that sometimes the ball bounces higher. Later, while filling the basketballs with air you notice that the amount of air in the basketballs can be different.
Prediction::
Increasing the air in a basketball will/will not make it bounce higher.
Observation #1p. 4
Hypothesis:
If the amount of air in a basketball is increased, then it will bounce higher.
Question:
Prediction:
Will increasing the height of a ramp cause a car to travel farther?
Cars on higher ramps will/will not travel farther.
Observation #2p. 4
Hypothesis:
If the height of a ramp is increased, then a car will travel farther.
While watching your brother play with his toy cars, you notice when he rolls them down a ramp that they travel different distances. You wonder if the height of the ramp has any affect on how far the cars travel.
1. Will soaking seeds in water affect sprouting time?
Hypothesis:
Hypothesis:
Hypothesis:
If seeds are soaked in water, then seeds will sprout faster.
2. Will freezing popcorn affect the amount of kernels that pop?If popcorn is frozen, then more kernels will
pop.
If the temperature of water is increased, then sugar will dissolve more quickly.
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3. Will increasing the temperature of water affect the amount of time it takes sugar to dissolve?
4. Does the temperature at which bread is stored affect mold growth?
Hypothesis:
Hypothesis:
If bread is stored at a cooler temperature, then mold will grow more slowly.
5. Does water temperature affect the time it takes water to freeze?
If water temperature is decreased, then water will freeze more quickly.
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i. A variable is i. A variable is any factor in an experiment that can change..
vi.vi.A dependent variable is expressed in your A dependent variable is expressed in your hypothesis afterhypothesis after
the word the word “then”.“then”.
iii. The independent variable is iii. The independent variable is the factor you want to test..
ii. Constants are ii. Constants are all of the factors that are the same..
III. Determining Variables and ConstantsIII. Determining Variables and Constants
a. Variables and Constantsa. Variables and Constants
iv.iv.An independent variable is expressed in your hypothesis An independent variable is expressed in your hypothesis after the word after the word “If”.
v. The dependent variable is v. The dependent variable is the factor that you measure to get your results.
Hypothesis #1 : If the amount of air in a basketball is
increased, then it will bounce higher.
Hypothesis #2: If the height of a ramp is increased, then a car will travel farther.
Independent variable:
Independent variable:
Dependent variable:
Dependent variable:
amount of airamount of air
height of bounceheight of bounce
ramp heightramp height
distance traveleddistance traveled
1. If seeds are soaked in water, then seeds will sprout faster.
Independent variable:Dependent variable:
2. If popcorn is frozen, then more kernels will pop.
Independent variable:Dependent variable:
3. If the temperature of water is increased, then sugar will dissolve more quickly.
Independent variable:Dependent variable:
sprouting sprouting timetime
percent of kernels poppedpercent of kernels popped
dissolving timedissolving time
soaking seedssoaking seeds
freezing popcornfreezing popcorn
water temperaturewater temperature
4. If bread is stored at a cooler temperature, then
mold will grow more slowly.
Independent variable:Dependent variable:
5. If water temperature is decreased, then the water will freeze more quickly.
Independent variable:Dependent variable:
storing temperaturestoring temperature
water temperaturewater temperature
time it takes mold to growtime it takes mold to grow
freezing timefreezing time
i. An operational definition is i. An operational definition is a description of the particular way in which you will measure the dependent variable.
ii. Operational definitions can be ii. Operational definitions can be qualitative oror quantitative.
b. Measuring the Dependent Variableb. Measuring the Dependent Variable
Defining Variables Operationally
Hypothesis: If students have more lunch money,then they will eat a poorer quality diet.If students spend more time studying each week,then they will do better in school.
If fertilizer is added to tomato plants,then they will grow better.
Hypothesis:
Hypothesis:
Identifying Variables
1. What variables can affect the rate at which seeds sprout?
2. What variables can affect the number of popcorn kernels that pop?
temperaturesunlighttype of seedsoil
type of popcornpopping timemicrowavepopcorn brand
soaking seedssoaking seeds
freezingfreezing
3. What variables can affect the dissolving rate of sugar in water?
4. What variables can affect mold growth on bread?
type of sugaramount of sugaramount of waterstirring
type of breadstorage containeramount of sunlight/darknessmoisture in bread
storing temperaturestoring temperature
water temperaturewater temperature
5. What variables can affect the time it takes water to freeze?
containeramount of waterfreezerlocation and temperature in freezer
water temperaturewater temperature
Hypothesis #1 : If the amount of air in a basketball is
increased, then it will bounce higher.Independent variable: Dependent variable:
amount of airamount of air height of bounceheight of bounce
The The constants are all the factors that are the same. are all the factors that are the same.
same basketballsame basketball
same surfacesame surface
same bounce heightsame bounce height
same temperaturesame temperature
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Hypothesis #2: If the height of a ramp is increased, then a car will travel farther.
Independent variable: Dependent variable:ramp ramp heightheight
distance traveleddistance traveled
Constants:Constants:
same carsame car
same rampsame ramp
same surfacesame surface
Hypothesis: If seeds are soaked in water, then they will sprout faster.Hypothesis: If seeds are soaked in water, then they will sprout faster.
Independent variable:Independent variable: soaked soaked seeds seeds
sprouting sprouting timetime
Dependent variable:Dependent variable:
Constants:Constants:
Hypothesis: If popcorn is frozen, then more kernels will pop.Hypothesis: If popcorn is frozen, then more kernels will pop.
Independent variable:Independent variable:freezing freezing kernels kernels Dependent variable:Dependent variable:percentage of popped kernelspercentage of popped kernels
ConstantsConstants
Hypothesis: If the temperature of water is increased, then sugarHypothesis: If the temperature of water is increased, then sugar will dissolve more quickly.will dissolve more quickly.
Independent variable:Independent variable:water water temperaturetemperature
Dependent variable:Dependent variable:dissolving timedissolving time
ConstantsConstants
Hypothesis: If bread is stored at a cooler temperature, then mold willHypothesis: If bread is stored at a cooler temperature, then mold will grow more slowly.grow more slowly.
Independent variable:Independent variable:storing temperaturestoring temperature
Dependent variable:Dependent variable:mold growthmold growth
ConstantsConstants
Hypothesis: If water is decreased then freezing time will decrease.Hypothesis: If water is decreased then freezing time will decrease.
Independent variable:Independent variable:water water temperaturetemperature
time it takes to time it takes to freezefreeze
Dependent variable:Dependent variable:
ConstantsConstants
Mr. Hunsicker has observed that the batteries in his boom box seem Mr. Hunsicker has observed that the batteries in his boom box seem to last longer if he plays his boom box at low volume rather than high to last longer if he plays his boom box at low volume rather than high volume. He wants to design an experiment to determine if this is true.volume. He wants to design an experiment to determine if this is true.
If a boom box is played at low volume, then the batteries will last longer.If a boom box is played at low volume, then the batteries will last longer.
Independent variable:Independent variable:
Dependent variable:Dependent variable:
Constants:Constants:
boom box volumeboom box volume
battery lifebattery life
boom boxboom box
batteriesbatteries
CDCD
An investigator has observed that chickens lay more eggs at certain times of the year. It has also been observed that this occurs during the late springand summer months. An inference has been made that the extra eggs aredue to the longer daylight hours.
If the number of daylight hours is greater, then chickens will lay more eggs.If the number of daylight hours is greater, then chickens will lay more eggs.
Independent variable:Independent variable:
Dependent variable:Dependent variable:
Constants:Constants:
number of daylight hoursnumber of daylight hours
number of eggs laidnumber of eggs laid
chickenschickens
diet/waterdiet/waterhenhouse-climate/temperaturehenhouse-climate/temperature
Johnny made an observation that when he drove around the city on the
highway to work everyday, he did not have to get gas as often as when
he drove through the city. He then asked himself Do the type of roads I
drive to work on everyday affect my gas mileage?
If cars are driven on the highway, then gas mileage will increase.If cars are driven on the highway, then gas mileage will increase.
Independent variable:Independent variable:
Dependent variable:Dependent variable:
Constants:Constants:
type of street traveledtype of street traveled
gas mileagegas mileage
carcardriverdriver
type of gastype of gas
Troy wanted to determine if mold grows faster on moist Troy wanted to determine if mold grows faster on moist bread or dry bread.bread or dry bread.
He placed one piece of bread in a dry baggie and another He placed one piece of bread in a dry baggie and another piece of bread piece of bread
in a damp baggie. He checked them every eight hours and in a damp baggie. He checked them every eight hours and recordedrecorded
his observations.his observations.
If bread is moist, then mold will grow faster.If bread is moist, then mold will grow faster.
Independent variable:Independent variable:
Dependent variable:Dependent variable:
Constants:Constants:
moisture on breadmoisture on bread
mold growthmold growth
breadbread
temperaturetemperature
sunlightsunlight
Hannah wanted to test the ability of different drinks to dissolve bones. She filled glass jars with orange juice, milk, cola, and distilled water. Hannah then placed a chicken bone in each of the jars.
Independent variable:Independent variable:
Dependent variable:Dependent variable:
Constants:Constants:
different types of drinksdifferent types of drinks
dissolving of bonedissolving of bone
bones – size and typebones – size and type
amount of liquidamount of liquid
temperaturetemperature
Sarah wanted to determine which of three brands of Sarah wanted to determine which of three brands of popcorn popped the most kernels. She put one brand in the popcorn popped the most kernels. She put one brand in the microwave, set the timer for four minutes, and allowed the microwave, set the timer for four minutes, and allowed the bag to pop. She repeated this process for each bag.bag to pop. She repeated this process for each bag.
Independent variable:Independent variable:
Dependent variable:Dependent variable:
Constants:Constants:
brand of popcornbrand of popcorn
percent of kernels poppedpercent of kernels popped
microwavemicrowave
timetime
type of popcorntype of popcorn
a. When summarizing your data, look at all of your observations, Then look for meaningful ways to present your observations.
Growth Rate of a Child
Data TablesData Tables
Age (years)
Weight (kg)
GraphsGraphs
Line graphs are useful for showing Line graphs are useful for showing changes over time.changes over time.
The The independentindependent variable is placed variable is placedalong the x-axis.along the x-axis.
The The dependentdependent variable variableis placed along theis placed along they-axis.y-axis.
Bar graphs are useful for Bar graphs are useful for comparing datacomparing data..
The dependent variableThe dependent variableis placed along theis placed along they-axis.y-axis.
The independent variable is The independent variable is placedplacedalong the x-axis.along the x-axis.
Growth Rate of a Child
Age (years)
Weight (kg)
Birth 1 year 2 years 3 years 4 years 5 years
20
18
16
14
12
10
8
6
4
2..
..
..
..
....