Module 2: Air Flashcards
Humidity
the moisture content of air
heat index
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
absolute humidity
the mass of water vapor contained in a certain volume of air
relative humidity
a quantity expressing humidity as a percentage of the maximum absolute humidity for that particular temperature
what gasses make up the majority of air
nitrogen 78%; oxygen 21%
name two other gasses that are in our air
argon 0.9%; carbon dioxide 0.03%
what are two things carbon dioxide does to help maintain life on our planet?
- 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
- 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)
greenhouse effect
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
parts per million
the number of molecules (or atoms) of a substance in a mixture for every one million molecules (or atoms) in that mixture
what is the conversion formula to convert percent to parts per million?
1% = 10,000 ppm
does higher humidity make it feel warmer or cooler?
warmer
does water evaporate faster with low or high humidity?
low
why does sweating cool people down?
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
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?
The humidity is higher on the first day.
If you put a glass of water outside when the relative humidity is 100%, how quickly will the water evaporate?
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.
Why does sweating cool people down?
Sweat cools you off, because when it evaporates, it takes energy from your skin. When energy leaves your skin, it gets cooler.
What is the percentage of nitrogen in dry air? What about oxygen?
dry air is 78% nitrogen and 21% oxygen
What would be the consequence of removing all the carbon dioxide in earth’s air supply?
If the air had no carbon dioxide in it, the earth would be colder. Also, plants would die of starvation.
What would be the consequence of removing all of the ozone in earth’s air supply?
If there were no ozone in the air, ultraviolet light would kill all living things.
What would be the consequence of a sudden increase in the concentration of oxygen in the earth’s air supply?
If more oxygen were in the air, lifespans would decrease and forest fires would increase in frequency and ferocity.
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?
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.
What makes up the majority of the air that we exhale?
Nitrogen makes up the majority of the air we exhale.
Do we exhale more carbon dioxide or more oxygen?
We exhale more oxygen.
Is global warming happening today?
No. (Figure 2.4 shows that the average global temperature has been reasonably constant for the past 70 years.)
Is the air cleaner today, or was it cleaner 20 years ago?
The air is much cleaner today than 20 years ago. (See figure 2.6)
What is a cost/benefit analysis?
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.
What does a catalytic converter do in a car?
A catalytic converter converts carbon monoxide in the car’s exhaust to carbon dioxide.
What does a scrubber do in a smokestack?
A scrubber traps sulfur oxides in a smokestack and keeps them from being emitted into the air.
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?
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.
