Hi Erica,

Baily's Beads happen because the surface and thus the edge of the Moon are not completly smooth - there are montains and valleys.

The beads are the result of just a bit of sunlight shinning through valleys on the Moons edge (or "limb") right befor or after the Sun is completely covered up.

Here is a link with some pictures:

http://www.exploratorium.edu/eclipse/what2.html

Terry