Using the document camera, students can observe the reappearance of a penny at the bottom of a cup as water is added.

Fill the beaker halfway with water.

Place a penny in the bottom of the cup about 3/4 of the way away from the camera.  Place the cup on the document camera and adjust the camera so that the penny is just out of site over the rim of the cup.

Slowly add water, being careful not to disturb the penny, until the cup is about 3/4 full. Pre-wetting the cup and penny may help stick it in place.

The penny will slowly appear and finally become fully visible.