[thedoc (OP)]

Nozinhle Bee asked the Naked Scientists:
   I want to ask, that they say the higher you go the cooler it becomes, the thing but when we are on planet earth its hot , like climbing a mountain you find that its freezing as you go up. what happens to the sun when climbing its supposed to be hot. just asking for a clarification
What do you think?

[Atomic-S]

The intensity of solar radiation in the absense of obstructions varies inversely as the square of the distanct to the sun.  The sun is about 93,000,000 miles away. If you climb a 7 mile high mountain, that is an insignificant change. However, there will be a more significant increase in radiation because the air at that altitude is thinner, but even that is not enough to offset the change in pressure of the air between the bottom and top of the mountain, which is the main reason for the colder air.

[evan_au]

If you imagine a breeze hitting the side of a mountain, and the air is deflected upwards.

As the air rises, the air pressure reduces, and the average distance between air molecules increase.

The air molecules are slightly attracted to each other (by Van Der Waals forces), and it takes energy to pull them farther apart. This energy comes from the kinetic energy of the air molecules; at higher altitudes they don't move quite as fast, and we measure this as a reduction in air temperature as we go up the mountain.