Make your own balance

When I lived in Bangladesh a young entrepreneur used to come to our house with his mother in tow, selling freshly roasted peanuts. He used a balance of the kind I had only seen in illustrations about courts of law: "scales of justice." He had a rock on one side and he scooped an equal weight of peanuts onto the other side.

You can make a simple balance that is surprisingly accurate. It hinges on the coincidence that either one United States nickel or two pennies weigh almost exactly 5 grams.

Note that what follows is a 3 minute, crude design to get you on your way fast. Feel free to make it nicer or adapt the design to what materials you have available.

What you need

*2 (U.S.) nickels or 4 pennies (or anything else that weighs 5 grams)
*3' or 4' dowel,or a yard stick or meter stick, or any long stick
*thin string, thread or dental floss
* tape, scissors and an envelope

Step 1

Seal the envelope, then cut the envelope in half to make two pouches (or think of them as pockets: closed on three sides, open on one. These will hold the weights on either end of the balance.

Step 2

Tape the two halves of the envelope to either end of the dowel or stick. Using just one piece of tape might make them easier to empty.

Step 3

Tie the string or thread in the middle of the dowel or stick. Tie it loosely enough so you can slide it back or forth. Add the 5 gram weights to each envelope and slide the string until the stick balances by becoming horizontal.

Step 4

Take one of the weights out of one envelope half and put into that envelope some modeling clay that you think is 5 grams. Keep adding or taking away clay until you attain balance again.

Back to the Helicopter Instructions