Module 2: Air

Question 1

Humidity

Answer 1

the moisture content of air

Question 2

heat index

Answer 2

a combination of temperature and humidity; it tells you how hot you will feel as a result of humiditiy’s effect on the sweating process

Question 3

absolute humidity

Answer 3

the mass of water vapor contained in a certain volume of air

Question 4

relative humidity

Answer 4

a quantity expressing humidity as a percentage of the maximum absolute humidity for that particular temperature

Question 5

what gasses make up the majority of air

Answer 5

nitrogen 78%; oxygen 21%

Question 6

name two other gasses that are in our air

Answer 6

argon 0.9%; carbon dioxide 0.03%

Question 7

what are two things carbon dioxide does to help maintain life on our planet?

Answer 7

1. it is used in photosynthesis: plants convert carbon dioxide that they absorb from the air, and water they absorb from the ground into glucose, which is used for energy for the plant
2. it helps regulate the temperature of the earth by absorbing infrared light that the earth radiates; this in turn heats up the atmosphere to keep the earth warm (the greenhouse effect)

Question 8

greenhouse effect

Answer 8

the process by which certain gases (principally water vapor, carbon dioxide, and methane) trap heat that would otherwise escape the earth and radiate into space

Question 9

parts per million

Answer 9

the number of molecules (or atoms) of a substance in a mixture for every one million molecules (or atoms) in that mixture

Question 10

what is the conversion formula to convert percent to parts per million?

Answer 10

1% = 10,000 ppm

Question 11

does higher humidity make it feel warmer or cooler?

Answer 11

warmer

Question 12

does water evaporate faster with low or high humidity?

Answer 12

low

Question 13

why does sweating cool people down?

Answer 13

when the sweat evaporates from your skin, it takes energy in the form of heat from your body to do so, and this cools you down

Question 14

The temperature is the same at 1pm in the afternoon on 2 consecutive days. For a person who is outside working, however, the second day feels cooler than the first day. On which day was the humidity higher?

Answer 14

The humidity is higher on the first day.

Question 15

If you put a glass of water outside when the relative humidity is 100%, how quickly will the water evaporate?

Answer 15

The water will not evaporate. Since the relative humidity is 100%, the air cannot hold any more water vapor. As a result, no water will evaporate from the glass.

Question 16

Why does sweating cool people down?

Answer 16

Sweat cools you off, because when it evaporates, it takes energy from your skin. When energy leaves your skin, it gets cooler.

Question 17

What is the percentage of nitrogen in dry air? What about oxygen?

Answer 17

dry air is 78% nitrogen and 21% oxygen

Question 18

What would be the consequence of removing all the carbon dioxide in earth’s air supply?

Answer 18

If the air had no carbon dioxide in it, the earth would be colder. Also, plants would die of starvation.

Question 19

What would be the consequence of removing all of the ozone in earth’s air supply?

Answer 19

If there were no ozone in the air, ultraviolet light would kill all living things.

Question 20

What would be the consequence of a sudden increase in the concentration of oxygen in the earth’s air supply?

Answer 20

If more oxygen were in the air, lifespans would decrease and forest fires would increase in frequency and ferocity.

Question 21

Suppose astronomers found another solar system in which there was a sun just like our sun. Suppose further that a planet existed ni this new solar system which was just as far from its sun as is earth from our sun. Since the vast majority of energy that planets get comes from their suns, is it reasonable to assume that the new planet would have roughly the same average temperature as that of earth? Why or why not?

Answer 21

There is no reason to expect that the new planet will have the same temperature as earth. If it does not have essentially the same air, with all the same levels of all the greenhouse gases, then it will not have the same temperature.

Question 22

What makes up the majority of the air that we exhale?

Answer 22

Nitrogen makes up the majority of the air we exhale.

Question 23

Do we exhale more carbon dioxide or more oxygen?

Answer 23

We exhale more oxygen.

Question 24

Is global warming happening today?

Answer 24

No. (Figure 2.4 shows that the average global temperature has been reasonably constant for the past 70 years.)

Question 25

Is the air cleaner today, or was it cleaner 20 years ago?

Answer 25

The air is much cleaner today than 20 years ago. (See figure 2.6)

Question 26

What is a cost/benefit analysis?

Answer 26

A cost/benefit analysis attempts to determine whether or not to take an action by determining the benefits of that action as well as the costs. If the benefit outweighs the cost, then the action should be taken. If not, the action should not be taken.

Question 27

What does a catalytic converter do in a car?

Answer 27

A catalytic converter converts carbon monoxide in the car’s exhaust to carbon dioxide.

Question 28

What does a scrubber do in a smokestack?

Answer 28

A scrubber traps sulfur oxides in a smokestack and keeps them from being emitted into the air.

Question 29

In the US, there are many regulations aimed at decreasing the amount of ground-level ozone in the air, because ground level ozone is considered a pollutant. at the SAME TIME, THERE ARE MANY REGULATIONS AIMED AT INCREASING THE AMOUNT OF OZONE IN THE OZONE LAYER. DESPITE THE FACT THAT OZONE IN THE OZONE LAYER IS THE SAME AS GROUND-LEVEL OZONE, OZONE IN THE OZONE LAYER IS NOT CONSIDERED A POLLUTANT. INSTEAD, IT IS CONSIDERED AN ESSENTIAL SUBSTANCE> WHY?

Answer 29

Ground-level ozone is a pollutant because it is a poison, and it is where we can breathe it. Ozone in the ozone layer is not a pollutant because no one breathes that high up in the air, so its poisonous properties are unimportant. It is necessary in the ozone layer in order to block the sun’s ultraviolet rays.