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Eighth Grade Mid-Year Exam Review
Nature of Science Chapter – Scientific Problem Solving
Lesson 1 – Scientific Inquiry
Vocabulary: critical thinking, hypothesis, inference, observation, prediction, science, scientific law,
scientific theory, technology
1. Describe the steps of science inquiry/the scientific method.
2. Compare scientific theory and scientific law.
3. What is critical thinking? Be sure to look at critical thinking, skepticism, pseudoscientific information,
determining reliability, and fact vs. opinions.
Lesson 2 – Measurement and Scientific Tools
Vocabulary: description, explanation, International System of Units (SI), percent error, scientific notation
1. Why did scientists create the International System of Units (SI)?
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2. Identify the SI base unit and tool used to measure these quantities:
length
mass
temperature
force
3. SI Unit Prefixes – Identify the prefix (with symbol) and the meaning.
4. What is the difference between precision and accuracy in measurements?
5. Can measurements in an experiment be accurate but not precise?
6. Why is scientific notation a useful tool for scientists?
7. Earth’s circumference is about 40,000,000 meters. Write this in scientific notation.
8. Why calculate percent error in an experiment?
9. What conclusion can you draw if your percent error is too high?
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10. Percent Error Formula
11. Calculate the percent error if the experimental value of the density of gold is 18.7 g/cm^3 and the
accepted value is 19.3 g/cm^3.
Lesson 3 – Case Study
Vocabulary: constants, control group, dependent variable, experimental group, independent variable,
qualitative data, quantitative data, variable
1. How are dependent and independent variables related to each other in experiments?
2. What might be the independent and dependent variables in an experiment about a bridge collapse?
3. What two groups are essential in a controlled experiment?
4. What is the difference between an experimental group and a control group?
5. Why do experiments need a control group?
Chapter 1 – Describing Motion
Lesson 1 – Position and Motion
Vocabulary: reference point, position, motion, displacement
1. Explain why a description of a position depends on a reference point.
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2. What three things must be included in the description of position?
3. What words can be used to describe a reference direction?
4. How can you describe the position of an object in two dimensions?
5. What is the difference between distance and displacement? How do you calculate each one?
6. When are distance and displacement the same?
Chapter 2 – The Laws of Motion
Lesson 1 – Gravity and Friction
Vocabulary: force, contact force, noncontact force, gravity, mass, weight, friction
1. Compare contact and noncontact forces.
2. Forces have two characteristics - ______________________ and ____________________.
3. What is the SI unit for force?
4. Arrows are used to show forces. What does the length of the arrow show?
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5. What is one way a person can apply a force to an object and not affect the direction of motion of the
object?
6. What factors determine the amount of gravitational force between two objects?
7. What is the law of universal gravitation?
8. What is the relationship between mass and weight?
9. Why is the gravitational force that a friend exerts on you less than the gravitational force exerted on
you by Earth?
10. What would the weight of a 110kg object on Earth? On the space station?
11. Compare static friction, sliding friction, and fluid friction.
12. How does friction affect the motion of two objects sliding past each other?
13. What causes friction?
14. How do lubricants reduce friction?
Lesson 2 – Newton’s First Law
Vocabulary: net force, balanced forces, unbalanced forces, Newton’s first law of motion, inertia
1. When combining forces in the same direction, how do you determine the direction of the net force?
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2. How do you calculate the net force on an object if two forces are acting on the object in the same
direction?
3. What would be the net force if one boy pushed with 250 N and another boy pushed in the same
direction with 180 N?
4. If two students are pushing on a dresser with a combined force of 100 N, and the dresser does not
move, then what do you know about the static friction between the dresser and the floor?
5. How do you calculate the net force on an object if two forces are acting on it in opposite directions?
How can you tell in which direction the object will move?
6. What is the net force on an object if one person applies a force of 100 N to the right and another
person applies a force of 50 N to the left?
7. What is wrong with the following statement: Objects always move in the direction of the applied
force?
8. What is the relationship between balanced forces and the motion of an object?
9. What is the relationship between unbalanced forces and the velocity of an object?
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10. What happens to the velocity of a moving car if the forces on it are balanced?
11. How is motion related to balanced and unbalanced forces?
12. What effect does inertia have on the motion of an object?
13. Which has greater inertia: a moving toy car or a large truck parked in a lot? Why?
14. Why do objects in motion stop moving?
15. Compare friction and inertia.
Lesson 3 – Newton’s Second Law
Vocabulary – Newton’s second law of motion, circular motion, centripetal force
1. What could happen to the motion of a moving car that encounters an unbalanced force?
2. What is wrong with the statement: Applied forces always change the motion of objects?
3. What happens to the speed of a wagon rolling to the right if the net force to the right acts on it?
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4. Do unbalanced forces always cause moving objects to change direction?
5. How does the way unbalanced forces affect objects at rest compare to the way unbalanced forces
affect the motion of moving objects?
6. How do the statements “unbalanced forces change the velocity of an object” and “unbalanced forces
make an object accelerate” relate to each other?
7. What is Newton’s second law of motion? What is the formula?
8. What would the acceleration of a 20 kg object upon which a net force of 50 N was exerted?
9. Solve the practice problems at the bottom of page 65.
10. How does circular motion differ from linear motion?
11. If an object is traveling along a curved path at a constant speed, does that mean its acceleration is
constant?
12. In which direction does centripetal force act?
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13. How does centripetal force affect circular motion?
14. How does the direction of the velocity of a satellite differ from the direction of its acceleration?
15. Why does the Moon orbit Earth instead of the Sun?
Lesson 4 – Newton’s Third Law
Vocabulary – Newton’s third law of motion, force pair, momentum, law of conservation of momentum
1. When you are standing, you push on the floor and the floor pushes on you. How do the directions
and strengths of these forces compare?
2. What is Newton’s third law of motion?
3. How are the forces in a force pair related?
4. Why don’t the forces in a force pair cancel each other?
5. How does Newton’s third law apply to the motion of a bouncing ball?
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6. What is the momentum of an object at rest?
7. How is it possible for a car to have more momentum than a large elephant?
8. How could you use the game of baseball to explain the difference between inertia and momentum?
9. What is the momentum formula?
10. Solve the problems at the bottom of page 73.
11. What is the law of conservation of momentum?
12. How does Newton’s third law of motion relate to the law of conservation of momentum?
13. Compare elastic and inelastic collisions.
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