Can you please help me with this lab?

Question

By answering simple questions? http://tinypic.com/view.php?pic=axcuu1&s=3

Answer 1

What should happen is that the cans roll closer to each other.

why? the scientific name is the Bernoulli effect, air moving faster creates lower pressure, so the space between the cans has a lower pressure and the air on the outsides of the cans pushes them together.

Practical uses: this is what makes an airplane fly, the curve of the wing moves the air farther over the top of the wing, and therefore faster than the underside, therefore creating "lift" on the  wing.