how does the atmosphere change at high altitudes?

Since this is not my area of expertise, I searched Google under the key words "atmosphere altitude Earth" to get these possible sources:

http://en.wikipedia.org/wiki/Earth's_atmosphere
http://www.grc.nasa.gov/WWW/K-12/airplane/atmos.html
http://www.enchantedlearning.com/subjects/astronomy/planets/earth/Atmosphere.shtml
http://scipp.ucsc.edu/outreach/balloon/atmos/The%20Earth.htm
http://www.sciencemadesimple.com/sky_blue.html

In the future, you can find the information you desire yourself, if you use appropriate key words to do your own search.

I hope this helps. Thanks for asking.

it really didn't help at all im more confused then ever

How does the atmosphere change at high altitudes? It is a really broad question.

The air density is much less.
The composition of the air changes.
Ions appear in the far upper levels of the atmosphere.
Temperature is very low.

The third link is pretty good. On a vague question such as this in a technical area, it is very difficult to answer.

thanks i know these questions i have to anwser are broad questions sorry its a worksheet