MAKE A BALANCE BEAM SCALE

Introduction: Build a small balance by making a hole in the middle of a stick and hanging it by a string. Use wire to hang pans on each end and you have a good balance that cost nothing. For weights, cut wire to the correct length and file to exact weight. Or use coins or lead shot as weights and determine their weight at school on a good balance. Test your balance by move the loads to the opposite pans. If still in balance then your balance arms are equal.

MATERIALS NEEDED:

Thin, straight plastic tube, stick or cane (60 cm long)

Two plastic or Styrofoam plates or saucers. The lids of metal cans work as well.

Thread or string

Some coins that may be used as weights.

PROCEDURE

The saucers can be turned into pans for the balance by piercing three holes at equal distances around the rims of each pan. Tie the ends of 18 inch long pieces of string to these holes. Join the other ends of the three strings and tie them together so that the pan will be level when suspended from the strings. Secure each suspended pan to opposite ends of the stick or rod you have selected as the beam.

The next step is to find the place on the beam where the weight is equally distributed between both ends and the beam is level. This can be done by loosely tying a string near the center of the beam and moving it back and forth while the whole scale is hanging from this central string. When the beam is level, you can simply stand back and check it by sight, tie the string tightly so it cannot slip. 
(If you are using a wooden dowel, you may make a hole for string to go through.)

You have now created one of the most basic weighing scales. Variations on this simple scale are still in use in markets all around the world. To put it to use you have to have a set of weights. You can use coins or beads as weights. 

• US Penny = 2.5 gram

• US Nickel = 5 grams

• US Dime = 2.25 grams

• US quarter = 5.5 grams

If you live out of US, you may weight your local coins, or some beads or beans in a local grocery store and then use them as weight. For example you may buy 100 grams of same side plastic beads and then count them. Divide the weight by the number of beads, so you will know the weight of each bead and you can use them as weights.