Grade 7 General Science: Second Semester Study Guide – ANSWER KEYEXAM DATE: Friday, May 30 at 9amTo make you more comfortable with the exam format and the amount of each type of question, we have created this addition to the study guide, which contains the instructions for each section of the exam. We recommend that you read them carefully.PART 1: ELECTRICITY (27 QUESTIONS)A. Answer the multiple choice questions. (11 points) B. Decide if the each statement refers to static (S) or current (C) electricity. Then circle the correct choice on your answer sheet. (5

points)C. Use the word bank to fill in the blanks of the following statements and diagrams. Write the letter of the correct answer in the

space provided on your answer sheet. Answers may only be used once. Some answers may not be used at all. (7 points)D. Short answer questions. Draw diagrams. Explain concepts. (9 points)PART 2: LIGHT, WAVES, AND THE ELECTROMAGNETIC SPECTRUM (30 QUESTIONS)A. Mark each sentence as true or false by circling the letter T or F on your answer sheet. Then, if a statement is false, change the

underlined term to make the sentence true by writing the correct term in the space on your answer sheet. (8 points)B. Lenses and Mirrors: Use Figures 1 and 2 for questions. Write your answers in the space provided on your answer sheet. (4

points)C. Match the terms on the right with the letters on the diagrams on the left. (9 points)D. Multiple choice questions (4 points).E. Short answer: Answer in the space provided on your answer sheet. (10 points)PART 3: BIOLOGY (55 QUESTIONS)A. Use the word bank to fill in the blanks. Write the letter of the correct answer in the space provided

on your answer sheet. (10 points)B. Use the word bank to determine the appropriate labels. Fill in the letter of the correct label on your answer sheet. Each term will be used exactly once. (1 point each - 23 points)C. Short answer questions. (16 points)D. Use the word bank to fill in the blanks. Write the letter of the correct answer in the space provided on your answer sheet. Also

multiple choice questions. (9 points)E. Short answer questions. (14 points)F. Decide if the statement or picture is describing active transport (AT), diffusion (D), or Osmosis (O). Then circle the correct option

on your answer sheet. (1 point each – 6 points)PART 4: INVENTION CONVENTION (5 QUESTIONS)A. Read the article. Answer the questions explaining how it relates to the engineering design cycle (the steps we followed to build our inventions). (9 points)

Vocabulary for Second Semester Exam (see your class’s Google Presentation) Electricity Electromagnetic

SpectrumBiology (including the Microscope)

1. static electricity2. neutral atom3. charged atom or ion4. law of conservation of charge5. spark6. current electricity7. conductor8. insulator9. open circuit10. closed circuit11. switch12. fuse13. circuit breaker14. short circuit

1. wave2. wavelength3. crest4. trough5. amplitude6. reflection7. law of reflection8. normal9. incident ray10. reflected ray11. angle of incidence12. angle of reflection13. plane mirror14. refraction15. convex lens16. concave lens17. electromagnetic

spectrum18. nearsighted19. farsighted

1. eyepiece2. body tube3. arm4. revolving nosepiece5. fine adjustment

knob6. coarse adjustment

knob7. objective lens8. ocular lens9. stage10. stage clips11. diaphragm12. light source13. base14. cell membrane15. cytoplasm16. nucleus17. mitochondrion18. chromosome19. lysosome

20. chloroplast21. endoplasmic reticulum22. ribosome23. Golgi bodies24. cell wall25. vacuole26. selectively permeable

membrane27. diffusion28. osmosis29. active transport30. photosynthesis

INSTRUCTIONS: Use your notes in your binder or book to answer the following questions and define the terms at the end.

Electricity1. Describe how the following pairs of objects act with respect to one another:

a. 2 positively charged objectsThey will repel because they have the same charge.

b. 2 negatively charged objectsThey will repel because they have the same charge.

c. 1 positively charged and 1 negatively charged objectThey will attract because they have opposite charges (opposites attract).

2. How do you use friction to charge an object? a. Describe what happens.

You rub two objects together. The electrons of one object transfer to the other object. The object that gained electrons now has a negative charge (because electrons are negative). The object that lost electrons now has a positive charge.

b. Draw a diagram of what an object is like before and after it is charged.

3. A neutral fluorine atom has 9 electrons, protons, and neutrons.a. What charge would it have if it gained an

extra electron? b. What do we call this type of atom?

Negative charge It is an atom with charge – an ION.4. If you rub a balloon on your head, the balloon will steal electrons from your hair. Then the balloon can stick to a wall.

a. Why is this happening? The balloon became negative when it stole electrons from your hair. The wall is neutral, but neutral things are attracted to objects with charge. This is because the electrons in the balloon repel the electrons in the wall. Then the negative balloon is attracted to the positive protons in the wall.

b. Use a diagram that shows the movement of electrons to help with your written explanation.

5. What is electrical discharge?Electrical discharge is when an object with static electricity loses its charge – this usually happens in the form of a spark or a shock.

a. Give an example of when you saw it happen in the labWe saw this in the lab when the Van der Graaf generator shocked us – you could even sometimes see the sparks jump from the machine to our hands.

b. Give an example of when you saw it happen in nature.In nature, lightening is an example of discharge – the static electricity in the clouds discharges into the earth.

6. What is the difference between insulators and conductors? Give an example of each.The difference between insulators and conductors is that insulators block the flow of electricity while conductors let electricity flow through them. Examples of insulators: plastic, rubber Examples of conductors: wire, anything metal, water (why electricity and water shouldn’t mix)

7. Draw a picture of a light bulb in a closed circuit.

a. In your diagram be sure to label the battery, wires, switch, and light bulb.b. Is the light bulb on or off? Why?

The light bulb is on because the switch is closed – this means there is a complete path for the electricity to flow.

8. Compare and contrast fuses and circuit breakers in a Venn diagram.Fuses Similar Circuit Breakers- Found in boxes or inside plugs- One time use- Has a thin metal wire inside that melts when too much electricity is flowing

- Turn off circuits when too much electricity flows- Prevent fires- Safety device

- Found in a circuit breaker box- A switch that automatically turns off a circuit when too much electricity is flowing

9. Compare and contrast static and current electricity in a Venn diagram.Static Electricity Similar Current Electricity- The build up of charge in an object- Can happen in nature or in a laboratory- Objects will eventually discharge

- Both are forms of electricity- Both involve electric charges- Both can be dangerous

- The flow of electric charge through a circuit- Used to power different devices and to keep machines running- Must have a closed circuit and a power source to work

Electromagnetic Spectrum1. In what 2 ways did we describe light as capable of moving?

Light can move as a WAVE or a RAY.

2. Draw a wave and label the wavelength, amplitude, crest, and trough.

3. What is the relationship between the angle of incidence and the angle of reflection in a reflected light ray? What do we call this relationship?The angle of incidence and the angle of reflection are always the same. We call this the Law of Reflection.

a) Troughb) Amplitudec) Wavelengthd) Creste) Resting position

4. Draw a diagram of a light ray as it is reflected froma. a plane mirror

b. convex mirror AND c. concave mirror

5. Draw a diagram of what happens to three light rays as they move through each type of lens. Have 1 of the rays go through the exact center of each lens.

a. a convex lens b. a concave lens.

6. Use a diagram and written explanation to describe what happens when a ray of white light hitsa. a white shirt b. a black car c. a magenta butterfly.A white shirt reflects all colors of light.A black car absorbs all colors of light.A magenta butterfly absorbs most colors of light but reflects red and blue light (red and blue make magenta).Another example: A blue chair reflects blue light and absorbs all other colors.

7. Explain and draw a diagram to show how lenses can be used to correct the vision for a patient that isa. near-sighted b. far-sighted.

Biology1. Label all of the parts of the microscope we studied in class.

2. Draw a diagram of a plant cell and label all of the parts studied in class.Parts you need to know: cell wall, cell membrane, nucleus, mitochondria, chloroplast, endoplasmic reticulum, golgi body, lysosome, cytoplasm, ribosome, vacuole (IGNORE ALL OTHER LABELS). Lysosomes not in picture but are small circle within a cell.

3. What are the organelles we find in a plant cell that we do not find in animal cells? What does it look like?Plant cells have cell walls and chloroplasts – animal cells have neither of these.

4. Compare and contrast plant cells and animal cells. Use a Venn diagram to organize your answer.Plant Cells Similarities Animal Cells- Have cell wall- Have chloroplasts that do photosynthesis (make food)- Have much bigger vacuole- Few lysosomes

- Both are cells- Have cell membrane, nucleus, endoplasmic reticulum, ribosome, golgi apparatus, mitochondria, vacuole, lysosome, cytoplasm

- No cell wall- No chloroplasts (can’t make food inside cell)- Have smaller vacuoles- Many lysosomes

5. What are the 3 main functions of the cell membrane?The cell membrane controls what comes into the cell, controls what leaves the cell, protects the cell, and gives it support.

Eye piece with ocular lens

Eyepiece/body tube

Arm

StageCoarse Adjustment Knob

Fine Adjustment Knob

Base

Nosepiece

Objective Lenses

Stage clips

Condenser or DiaphragmLight source

NOTE: be able to recognize the parts – the labels are not in the same order on the test!

6. Describe the 3 processes by which materials may leave or enter a cell. In your answer include (a) concentrations and movement of particles, (b) types of particles moved, and (c) is energy needed?The three processes are diffusion, osmosis, and active transport.Diffusion: any kind of molecules move from an area of high concentration (where there are a lot of those molecules) to an area of low concentration (where there are few or none of those molecules). No energy is needed.Osmosis: the diffusion of water molecules across a membrane from an area of high concentration (where there are a lot of water molecules) to an area of low concentration (where there are few or no water molecules). No energy is needed.Active Transport: when molecules are moved from area of low concentration (where there are few of these molecules) to areas of high concentration (where there are lots of those molecules). Energy is used to do this. Sodium (Na) ions are a major example of this.

7. Draw a picture of a cell with a high concentration of sodium ions outside and a low concentration inside. Label the cell membrane and a sodium ion and draw arrows to show in which direction the sodium ions will move.

8. Is the example above and example of diffusion, osmosis, or active transport? Why?Any example with sodium ions is an example of active transport. Sodium ions are pumped out of the cell using energy, from an area of low concentration to an area of high concentration.

9. Explain what the difference between diffusion and osmosis is.Osmosis is a type of diffusion. It is when WATER molecules move through a membrane from an area of high water concentration to an area of low water concentration.

10. Explain how you would calculate the magnification of a specimen you are looking at under the microscope. (low, medium, high)To calculate how much you are magnifying a specimen (the thing on the slide), you multiply the power of the ocular lens by the power of the objective lens.Example: the ocular lens is 10x power and the objective lens you are using is 4x power. 10 x 4 = 40 so the specimen is magnified to look 40 times bigger than it really is.

11. If a Euglena cell was moving to the right in the field of view of the microscope, in what direction would you have to move the slide to keep watching it? Why?

You will have to move the slide to the left. Due to the shape of the lenses in the microscope, everything gets flipped.

12. List two tips for properly handling a microscope slide.Hold it carefully. Only hold it from the sides. Attach it to the microscope with stage clips.

13. Explain the process of photosynthesis. What are the reactants in this process? What are the products in this process?Photosynthesis is a process that happens in the chloroplasts of plant cells. Sunlight, water, and carbon dioxide are the reactants that react to produce food (glucose) and oxygen.

Invention Convention

1. Explain each of the steps used in the invention convention project (the steps of the engineering design cycle). Describe what should be done in each step using a specific example.

These are the steps we followed in the Invention Convention. See the following page.

The sodium example is the one on the right (labeled active transport). The sodium ions are the orange squares. Energy (ATP) is being used to take the sodium ions across the membrane from where there are only 2 sodium ions to where there are already 5 sodium ions (from low to high concentration).