1. Name the three kinds of strength used to characterize materials AND give an example of a material that are strong in each of these modes.
2. What kinds of bonding occurs in each of the three materials you listed in question #1?
3. Explain how atoms can be arranged in such a way to create a permanent magnet.
4. Identify 10 objects in your home that use semiconductors. What other kinds of materials with special electrical properties are found in all of these 10 objects?
5. Research the status of magnetically levitated trains like the one now operating in China. How does it operate? How fast might it go?
6. How does a nuclear reactor work?
7. What types of researchers and scientists use carbon-14 radiometric dating? What type of researcher would use the other isotopes such as uranium-238?
8. Use the periodic table to identify the element, its atomic number, mass number and electrical charge of the following:
|
# Protons
|
# Neutrons
|
# Electrons
|
Element Symbol
|
Atomic Number
|
Mass
|
Electrical Charge
|
|
1
|
0
|
1
|
|
|
|
|
|
8
|
8
|
8
|
|
|
|
|
|
17
|
18
|
18
|
|
|
|
|
|
36
|
50
|
36
|
|
|
|
|
9. Potassium-40 decays into argon-40 with a half-life of 1.2 billion years. A particular mineral grain is known to have had a million potassium atoms in its crystal structure when it formed. When the grain was ground up, scientists discovered 750,000 atoms of argon-40. When did the grain form? (Hint: Use Figure 12-10 on page 272 to obtain a qualitative estimate).
10. What are the half-lives of the following common isotopes:
o Carbon-14:
o Uranium-238:
o Uranium-235:
11. What is a particle accelerator?
How do scientists use particle accelerators to study subatomic particles?
12. What particle is exchanged to generate each of the four fundamental forces?
13. What medical technologies (e.g. PET) rely on the physics of elementary particles?
What are the benefits of noninvasive procedures such as PET?
14. How is astronomy the oldest science?
15. How does the energy produced at the core of the Sun reach the photosphere?
16. Why won't the Sun become a supernova or black hole?
17. Why does the existence of the cosmic redshift lead to the big bang picture of the universe?
18. If a galaxy is 1,000 Mpc away, how fast is it receding from us?
19. The average temperature of the universe is 2.7 Kelvin. What is that temperature in degrees Fahrenheit?
20. The Milky Way has a radius of approximately 100,000 light years. How many miles is that? How long would it take you to travel across our galaxy if you were traveling at 50% the speed of light (be sure to show your work for full credit)?