Balance scales are used to compare unknown weights to known weights. We have a set of gram weights, including grams, decigrams, and centigrams. We're going to make our own gram weights, just for fun.

We'll put a weight onto one side of the scale, and then we can make our own weight to equal the manufactured weight. We can cut wires into small pieces and put them onto the other side of the scale until they balance. Or, we can roll aluminum foil into balls or rolls, adding more foil until our foil weight balances the scale.

So what? What can we do with such small weights?

We can weigh small things! We can weigh a few grains of sand, a pebble, a teaspoon of sugar or salt (do they weigh the same?), a paper clip, or just about any very small item.

Weighing grains or particles can be messy. We can use a small piece of waxed paper (or foil) with the edges folded up for a tray. Make sure that we put a piece of waxed paper (or foil) exactly the same size, onto the side of the scale where we put the known weight. If we don't, we will not get an accurate weight.

If we make waxed paper (or foil) trays, we can even weigh talcum powder or flour!