* Warmer air contains more carbon dioxide than cooler air
* Warmer air has a lower density than cooler air
* The water molecules in warmer air are packed together more tightly than in cooler air.
Answers:
Point one - untrue - water evaporates into warm air. When it gets cooler the content stays the same until the temperature and altitude cause it to condensate out.
Point 2 - again incorrect - where does this miraculous change come from? Prepare to die a very quick death if this is true. The balance is critical so you need only a small variation to get tooo much of either one and both are poisons! Oxygen is actually more deadly!
Point 3. correct. That is why it rises as denser cold air falls!
Point 4. Wrong again. We are back to that condensation point again. Warm and cold air hold the same amount of water. Warm air will have lots of minute drops. Cold air will condensate them into larger drops which whilst farther apart are much larger and denser and thus the water molecule masses are much larger if further apart = Exacctly the same.
Warm air rises because hot air rises and cold air being denser, therefore heavier falls.
Basic Science!!!
C. lower density.
The commone answer textbooks give is because hot air is less dense.
But you need to understand what it means for an air molecule to be "hot". That means it travels faster. The hotter it is, the faster it travels; and vice versa, because these are one and the same thing.
To simplify the problem, suppose we have molecules distributed at random in a simple container, each molecule being either "hot" or "cold". Then the cold ones have little inclination to do much besides fall under the force of gravity, whereas the hot ones are more inclined to keep moving in random directions until they hit something and change to a new random direction of motion.
Because the cold molecules have a net downward motion compared to the hot ones, they eventually settle as low as they can, given what small random speeds they still have that keeps them stirred up. (At absolute zero, when they have no speed left, they would fall to the bottom of the container and stay there.) For the hot molecules, if they try to move down, they hit another molecule quickly and change direction because the cold molecules below are denser. If the hot molecule tries to move up, it is less likely to hit something and change direction because the molecules there are less dense. So the hot molecules spend much more time above than below because it is too difficult to keep moving downward when collisions occur so often.
Hope this helps some
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