Air pressure changes with altitude because of issues related to gravity. Molecules have more weight the closer they are to the Earth and more of them move to lower elevations as a result; this causes increased pressure because there are more molecules in number and proximity. Conversely, air at higher elevations has less weight, but also forces pressure on those layers below it, resulting in the molecules closer to the Earth supporting more weight, increasing the pressure
An ice cube causes hot coffee to become cool because the amount of coldness contrasts the hot coffee to make it a little cooler
Joey should say no to drugs next time he is offered to smoke weed
