Learn more physics!
If we "squished" air would we be able to see the air then?
- Anna (age 11)
You can actually see air even when it isn't squished. Think of the blue sky. What you're seeing there is blue light from the sun bouncing off air molecules toward your eyes.
It's hard to squish air at ordinary temperatures enough to see smaller volumes of it. However, if you cool air down enough it turns into a liquid. That's just air molecules (nitrogen and oxygen) squished together. Usually it's easier to find liquid nitrogen, which is safer to handle than liquid oxygen. You can pour it and see it much like the way you pour and see water. There's a picture here: http://en.wikipedia.org/wiki/Nitrogen
(published on 04/12/12)
Follow-up on this answer.