Mrs. Shaw’s 8 th Grade Midterm Review

1. Mrs. Shaw’s 8thGrade Midterm Review

2. 1. Which of these answers best describes a dependent variable? A. The things that stay the same from test A to test B to test C. B. The variable that is changed from test A to test B to test C. C. The thing that never changes. D. The thing that you measure.

3. 2. Jan noticed that when she put a tomato in water, it sank. When she put an apple in water, it floated. Why did the tomato sink while the apple floated? A. The apple has more surface area than the tomato, which allowed the apple to float. B. The apple is more dense than the water, and the tomato is less dense than the water. C. The tomato is more dense than the water, and the apple is less dense than the water. D. The apple and the tomato have the same density, but the tomato skin absorbed water, making it sink.

4. 3. A jeweler has two blocks of gold. The first block has a mass of 60 grams (g) and a volume of 3 cubic centimeters (cm3). The second block has half the mass and half the volume of the first block.What is the density of the smaller block of gold, in grams per cubic centimeter (g/cm3)? A. 5 g/cm3C. 20 g/cm3 B. 10 g/cm3D. 80 g/cm3

5. 4. How do you measure the volume of an irregular solid (like a rock)? A. water displacement method B. balance C. length x width x height D. centimeter ruler

6. 5. The amount of matter in an object times the gravitational pull on the object is called A. mass. B. density. C. weight. D. solubility.

7. 6. The ability of an object to burn is called A. conductivity. B. magnetism. C. reactivity. D. flammability.

8. 7. The characteristic of an object that can be observed without changing it is called a A. physical property B. reactivity C. chemical property D. flammability

9. 8. Matter is anything that A. has density and conductivity. B. has mass and takes up space (volume). C. can be seen. D. can be measured on a balance.

10. 9. What is the difference between a scientific theory and a scientific law? A. Scientific theories explain why something happens, and scientific laws describe what happens. B. Scientific theories require scientific evidence and scientific laws do not. C. Scientific theories are based on observation, and scientific laws are based on opinions. D. Scientific laws are frequently modified, but scientific theories are rarely changed as new information becomes available.

11. 10. Which statement best describes the nature of scientific explanations? A. They are based upon feelings. B. They are based upon unguided guesses. C. They are based upon analysis of data. D. They are based upon careful planning of experimental design.

12. 11. What is an example of a quantitative observation? A. My shoe is size 8. B. My shoe is white. C. My shoe is dirty. D. My shoe is stinky.

13. 12. What two particles are found in the nucleus of an atom? A. protons and neutrons B. neutrons and electrons C. electrons and protons D. electron cloud and neutrons

14. 13. The smallest unit of matter that cannot be divided and still be the same element is _______. A. a proton B. a neutron C. an electron D. an atom

15. 14. Which of these accurately describes the structure of an atom? A. A negatively charged central area surrounded by a positively charged cloud. B. A positively charged central area surrounded by a negatively charged cloud. C. A neutral central area surrounded by a negatively charged cloud.

16. 15. In 1969, Neil Armstrong became the first person to walk on the Moon. Video coverage showing the astronaut walking on the surface of the Moon gives the impression that he was bouncing while he walked. What is the reason for this? A. The astronaut's mass on the Moon decreases. B. The density of the astronaut on the Moon is higher than on Earth. C. The atmosphere of the Moon affects the way the astronaut is able to move. D. The astronaut's weight on the Moon depends on the Moon's gravitational force.

17. 16. Which of these is an element? A. Hydrogen Trioxide (H3O) B. Water (H2O) C. Carbon (C) D. Carbon Dioxide (CO2)

18. 17. How do we know whether an atom is neutral or has a charge (ion)? A. Compare the number of neutrons and electrons. B. Compare the number of neutrons and protons. C. Compare the number of protons and electrons. D. Compare the number of neutral particles and positive particles.

19. 18. Imagine that the label on a sunscreen product reads, “Recommended by nine out of ten doctors.” No other information regarding this claim is provided. Why would a scientist tell consumers to be wary of this statistical claim? A. Sunscreen products do not work. B. The supporting scientific data are missing. C. The claim cannot be reevaluated when new information is reported.

20. 19. A puddle of water that Kim observed on the way home from school had frozen into ice by the next morning. What caused this change? A. Energy was removed from the water molecules. B. Attractions between the water molecules decreased. C. The volume of water was reduced. D. The water had undergone a chemical change.

21. 20. What type of substance is produced when two or more different types of atoms chemically bond? A. element B. mixture C. compound D. homogeneous mixture