How to Make Gram Scales

Gram scales are used to measure the weight of an item in grams. You could buy an expensive electronic set of gram scales that will give you a very precise reading, but you can also make an accurate gram scale at home using common materials. The gram scales you make using this tutorial will measure the unknown weight of an item against the known weight of another item.

Things You'll Need

• Cotton string Ruler Scissors 3-ting binder Paper clip Scotch tape 2 sheets of paper Stapler 3-hole punch (optional) 2 or 3 thick, heavy books Pennies

Instructions

1. Wrap a length of cotton string around the ruler 3 times. Measure 2 inches more and then cut. Tie the ends of the string together to form a loop. Place the loop in the center of the ruler. When holding the string with your fingers, the ruler should be balanced. If it is not balanced, you won't get an accurate reading from your gram scales.

2. Open the binder and stand it on a flat surface. Bend the paper clip open and attach it to the top of the binder, in the middle of the binding to form a hook. Hang the ruler on the hook by the loop in the string. As soon as the ruler is balanced when it stops moving, then tape the string in place. Take care not to obstruct the ruler from tilting when you tape or your gram scales won't work properly.

3. Fold each piece of paper in half, lengthwise. On the open end, fold down about 1/2 inch of the paper. Then, staple this end closed. You will now be left with two open ends. Staple one of them closed and leave one open to make a pocket. Make sure to use the same number of staples in each piece of paper so it won't affect the weight. Punch two holes in the top (now open) end of the paper to thread strings for hanging. You can use a hole punch or just use a pencil to poke holes if necessary.

4. Cut a 15-inch length of cotton string. Thread each end through one of the holes you punched in the piece of paper. Make a loop around one end of the ruler, 1 inch in, being as precise as possible. Tape the loop on the ruler once you have it correctly placed. Repeat this step for the second sheet of paper. The trays must hang down at an equal distance to ensure your gram scales work accurately.

5. Place your newly completed gram scales on top of 2 or 3 thick, heavy books. This will allow the scale room to move. Place a penny or two in one of the paper trays and the item you wish to measure in the other. A penny weighs 2.5 grams. If the item in the other tray is heavier than the penny, continue to add pennies until you have the correct weight.

Tips & Warnings

• If you don't have any pennies available to measure using your new gram scales, you can use a nickel instead. A nickel weighs 5 grams, which makes it easy to work with. A dime weighs 2.27 grams and a quarter weighs 5.67 grams.

• When using pennies to measure, check the date. Pennies that were printed before 1982 weigh 3.1 grams as opposed to the newer pennies which only weigh 2.5 grams and are easier to work with.