Water vapor in the air..?

Question

Thanks Curiosity for the other answers! What a big help!

Why do clouds usually form at the leading edge of a cold air mass? Is it because cold air contains more dust particles than warm air or is it because cool air flows under warm air, causing the warm air to rise and cool. I think it is the second one, but how would that help form a cloud?

Answer 1

D

Answer 2

D-because air is warmest at this level-warm air can hold more water vapor than cool air. (as air temperature decreases, its capacity for holding water vapor decreases---also, as air rises its temperature decreases)

Moisture content increased because warm air has the capacity to hold more water vapor.  Relative humidity is a measure indicating how much water vapor is in the air compared to how much that air sample can hold.  The air sample at 60 degrees has a relative humidity of 51%.  When that air is warmed to 70 degrees, it can hold more water vapor.  Since the relative humidity of the air remained constant, the amount of humidity in that air had to increase to keep the relative humidity at 51%.

I am sorry but I do not understand your question about the aquarium.  Choice A. says "air in the aquarium".  Then you have water involved.  Where is the water?

If I correctly understand your last question with the diagram that you added, then I agree with you on your answer.  However, I may not understand your description.  Hopefully, someone else will give an answer along with an explanation.