B.3: 1-4, page 344

1.    Ultraviolet is more harmful than infrared radiation because it has energy and power. Its most energetic form can destroy bacteria and viruses, meaning that it can cause damage to human skin.

2.    When visible radiation is beamed through the atmosphere, it is scattered causing the blue sky and red sunsets. Another use of visible light is the energy it provides for photosynthesis. This is essential because from photosynthesis we obtain oxygen, which is necessary for human life.

3.    The dryer states have a higher fluctuation in weather because of their concentration of greenhouse gases. The more humid states obviously have more water vapor, which holds in the heat from the day. The more arid states do not contain high amounts of gas molecules meaning that the beams of radiation are not blocked as well during the day, and the heat is not kept in at night.

4.     

a.    If Earth had fewer gas molecules, the daytime would be hotter because there would be enough molecules to adsorb the radiation coming from the sun, therefore increasing the temperature.

b.    On the other hand, fewer gas molecules would cause nights to be cooler. This is because there would not be enough gas molecules to hold in the heat to maintain a steady temperature during the night.

Unit 4: Section B Summary: 1-8

1.    The higher the frequency of electromagnetic radiation, the more energy it contains.

2.    The word “spectrum is a good descriptor because it is defined as a broad sequence of related quantities.

3.    Visible light assists photosynthesis because it can energize electrons in some chemical bonds. Infrared radiation does not contain enough energy, and ultraviolet is too harmful.

4.    Electromagnetic Radiation:

a.    Infrared radiation, visible light, and ultraviolet radiation.

b.    Infrared is basically heat energy and affects the temperatures of nonliving and living things, including Earth. Visible radiation powers plant photosynthesis, which releases oxygen into the atmosphere. Ultraviolet, in its one of its most energetic states, is linked to skin cancer, but the vitamin-D it provides is necessary for human health.

5.    Visible radiation does not provide enough energy to be able to sterilize lab goggles. Ultraviolet light, on the other hand, has photon with enough energy to break covalent bonds (in its UV-C form) therefore killing and destroying bacteria and viruses.

6.    Infrared radiation is mostly absorbed by carbon dioxide and water vapor in the atmosphere and does not reach the Earth’s surface, however, some its higher energy waves are absorbed by the earth and re-radiated as infrared energy. 90% of the visible radiation emitted from the sun reaches the earth and is scattered by water, air, and dust, casing the red sunsets and blue skies. Ultraviolet radiation in general does not reach the earth’s surface. UV-C is completely absorbed by the stratosphere, and most UV-B and UV-A radiation is absorbed by the ozone layer as well.

7.    Solar radiation that reaches Earth’s surface increases its temperature after being trapped by greenhouse gases such as carbon dioxide, methane, and nitrous oxide. Another affect is the increase of water vapor. The more radiation, the hotter it gets causing more water to evaporate and enter the atmosphere.

8.    Heat capacity:

a.    A lake will heat up more easily than asphalt because it can store more heat.

b.    The cause of this is because water has a high specific heat capacity than asphalt and other land materials. 

Unit 2: Section D Summary: 7-13

                  

7.    An alloy is a solid solution consisting of atoms of two or more metals. They can be created through heat and modify the properties of metals.

8.    One alloy that is used commonly is brass. This is an alloy of copper and zinc and is used in plumbing, lighting fixtures, rivets, screws, and ships. Another common alloy is pewter. Pewter is a mixture of tin, copper, bismuth, and antimony and is used for figurines and other decorative objects.

9.    Carbon is a nonmetal that is a component of both steel and stainless steel.

10. An example of a well-defined compound is Ni3Al, a nickel and aluminum metallic alloy. It has a low density, but is very strong and is used in jet aircraft engines.

11. Semi-conductors, since they are not completely non-conductive, but not entirely strong conductors, are placed in between metals and nonmetals. This is because metals are good conductors and nonmetals are not, so putting the semiconductors in between is logical.

12. Some elements commonly used for doping semiconductors are boron, arsenic, and phosphorous.

13. Semiconductors are used for electronic devices like transistors and integrated circuits for computers. They also allow computers to process digital information. 

Unit 2: Section D Summary: 1-6

1.    An allotrope is a different form of an element that has distinctly different physical properties, but has to be in the same state as the original element (for example solid iron and molten iron have different properties but are not allotropes since one is a liquid).

2.    Oxygen and aluminum both form allotropes.

3.    Diamond, coal, and pencil lead:

a.     Diamond is a hard substance, does not conduct electricity, and is colorless. Coal is powdery and used for fuel. Graphite is black, slippery, electrically conductive, and soft.

b.    Their properties vary because of their structures.  Diamond has tightly knit bonds, while graphite’s bonds are looser, making it an ideal lubricant.

c.    The appearance, quality, usefulness, and quantity account for their costs.

4.    Engineered materials sometimes have different properties than their original substances to make them more durable and useful for a job.

5.     Ceramics can operate at high temperatures, rather than metals, and have very high melting points. However, ceramics are very brittle and can crack during rapid changes in temperature. For example, when an engine starts cooling down the ceramic will crack and could lead to engine failures.

6.    To make plastics more useful, increasing their resistance to heat would be useful. For example, accidentally placing a plastic plate on a hot surface will cause it to melt resulting in a sticky mess. Increasing their melting points would help avoid these inconveniences. Also, finding a new way to make plastics would decrease pollution and waste caused by plastic materials. Inventing a decomposable substance that is renewable would greatly please the public.

Unit 2: Section C Summary: 18-21

                                                                       (non renewable)

18. Reusing and recycling:

a.    Reusing is using items that can be refurbished or repaired, rather than sent to a landfill. Recycling is gathering certain items to be reprocessed, allowing them to be used again.

b.    Reusing: reusable water bottles and donating clothes to charity. Recycling: cardboard and tires can be recycled.

19. Renewable and nonrenewable resources:

a.    Renewable: trees, animal waste, fruits, and wind.

b.    Nonrenewable: nuclear power, minerals (copper, gold, silver), helium, and lignite (soft, brown fuel).

20. Recycling or reusing:

a.    Reusing

b.    Recycling

c.    Reusing

21. A light bulb is produced from plastics, chemicals and glass, while a newspaper contains plants and some chemicals. A newspaper can be thrown away in a trashcan, but light bulbs must be disposed of carefully taking into consideration the chemicals contained inside. The problem is the mercury, which incandescent light bulbs do not contain. When recycling, newspapers can just be shredded up and put into the cycle again, but light bulbs must be carefully taken apart.