Objects stay balanced when the center of mass is below the pivot point. The center of mass is the point on the pencil-wire-washer object where the mass (or weight) on each side is the same. In this case, the washer is very heavy compared to the pencil, so the center of mass is close to the washer. The pivot point is your finger.
When you push the pencil sideways, you raise the center of mass. Gravity pulls the mass back down, standing the pencil back up.
Mess Kits are single-serving experiments that allow kids to explore scientific concepts at their own pace. Visitors are encouraged to complete as many as they want! See all Mess Kits.