Essay Final Exam
1. If an experiment tested two variables at the same time, would the findings of the experiment be reliable? Explain.
2. Give two examples of what could cause scientists to change a hypothesis or theory they have formulated.
3. Can you think of any tools or technologies that might have developed from people’s observations of natural phenomena?
4. Describe a problem that was solved by development of a new technology and the steps of the solution process.
5. Why is an object’s mass a size-dependent physical property while its density is a size-independent physical property?
6. Using what you know about chemical change and the law of conservation of mass, explain why you think many communities no longer allow residents to burn fallen leaves each autumn.
7. How is americium-241 used in smoke detectors?
8. An astronaut in the space shuttle turns a screwdriver clockwise. The astronaut starts to rotate in a counterclockwise direction. Why does this happen?
9. You are worried about a severe storm in your area. You hear a weather broadcast that says that the storm is moving at a speed of 25 km/h. Is this all you need to know for safety? Explain why or why not in terms of speed and velocity.
10. You ride three full turns around on a merry-go-round horse. What is your displacement? Your speed is constant; is your velocity constant? Why or why not?
11. A dog on a chain is fastened to the side of a house.
a. As the dog pulls on the end of the chain, name one pair of action-reaction forces acting on the chain.
b. What are the balanced forces on the chain?
c. What happens to the forces on the chain if the dog pulls the chain away from the wall and runs to play?
12. Name the six types of simple machines and give an example of each, or what each might be used to do.
13. Explain why applying force to an object does not always result in work being done.
14. Even though work input should equal work output, explain why, other than on ideal machines, machines have an efficiency less than one.
15. If a machine cannot have more work output than work input, what advantage is there to using one?
16. Compare and contrast fixed pulleys with movable pulleys and pulley systems and discuss their respective mechanical advantages.
17. What are fossil fuels? Why is it important to find alternative energy sources?
18. Discuss two ways of collecting solar energy.
19. What are two advantages and two disadvantages of hydroelectric energy?
20. Which has more kinetic energy, a feather floating through the air or a rock on the ground? Explain.
21. Starting with the Sun, what energy transformations take place when cows graze in a meadow?
22. Describe how sound waves travel through matter.
23. Compare and contrast refraction and diffraction.
24. What is the difference between a mineral and a rock?
25. What are five things in your school building that come from minerals?
26. You are given a sample of a mineral. How might you go about finding out what kind of mineral it is?
27. What does sedimentary mean?
28. What is the relationship between ores and minerals?
29. What are some reasons a nucleus is important to a cell?