How to Make a 1 Gram Scale

Wrap the string around the ruler three times times. This will keep the ruler from slipping out when you weigh something. Leave an extra couple of inches and cut the string. You may want to heat the ends of the string to make sure it won't fray, especially if you're using nylon string.

Tie the two loose ends of the string together to form a loop and place it in the middle of the ruler. This creates a fulcrum point--if you hold the string the ruler should be balanced and sit horizontal. If it does not, you know you need to adjust your string more toward the center.

Open the binder a little bit more than 90 degrees and sit it on a flat surface standing up. Bend the paperclip out to form a hook shape that can be used to attach the string from the ruler onto the top of the binder's spine. The goal is to get the ruler to freely hang from the binder. The ruler should hang balanced. If it does not, just move the string around until the ruler hangs horizontally when it is still. Tape the string to the ruler.

Make a tiny pocket at the ends of each of the two pieces of paper. Do this by folding the two pieces of paper in half so you have two long pieces of paper. Fold up the papers about an inch along the bottom long edge, and do the same with only one of the shorter edges. Make sure to use the same number of staples on both of the two pieces of paper so the pockets will be the same weight, or your scales will be off. Punch a hole on each end of the pockets.

Measure and cut another length of string somewhere around 17 inches in length. Take one end and run it through one of the holes in the first paper pocket, then run the other end of the string through the other hole. This will create a loop around the pocket. Tie a large knot on the two ends of the string to prevent the string from pulling out of the holes. Repeat this step for the second paper pocket.

Hang one pocket from one end of the ruler by wrapping some of the excess string around the ruler a few times. Then hang the second pocket from the opposite end of the ruler. Make sure they are an equal distance apart. When you have them in the right place the ruler should hang balanced. Tape the string to the ruler.

Prop the two books underneath the binder. This should elevate the scale high enough to allow the pockets to hang freely.

Put the crisp dollar bill inside one of the pockets and put whatever object you wish to weigh in the other pocket. Any type of U.S. paper bills should always weigh exactly one gram, but the more weathered the bill the less accurate it may be. Since we know that the dollar bill in the first pocket weighs one gram, this allows us to gauge the weight of the object placed in the other pocket.

Put some coins in one of the pockets and put whatever you want to weigh in the other pocket. U.S. pennies made in 1983 and after should always weigh 2.5 grams each. Pennies made in 1982 or before weigh 3.1 grams. So if you place a 1989 penny in one pocket and the object that's in the other pocket weighs out heavier than the penny, you know that the object weighs more than 2.5 grams. Add more pennies until the two pockets are balanced and you can easily calculate how much the object weighs.