Science Projects And Inventions

YOU NEED:

• A hairpin

• A table knife                  

You can actually make a hair pin move along the edge of a table knife.

Place a hairpin over the edge of a table knife and hold the knife horizontally, with the hairpin leaning toward

you as shown in the illustration. Your arm must not rest on the table. Now even if you want to keep the knife

steady  it is not possible. The hairpin will be "moving" towards your hand. If you make the hairpin lean the

other way it will move forward and fall off the edge of the knife.

Instead of a hairpin, a straightened out paper clip bent it in the middle, will also serve the purpose.

HOW DOES IT WORK?

You  cannot prevent your hand from jiggling. Each jiggle lilts the pin a trifle. Because the hairpin is in a slanting

mode, it stops at a place some distance along the knife blade. If the hairpin is made to lean the other way it will

crawl in the opposite direction.