How to Make Scales Out of Paper

Scales have been used for hundreds of thousands of years to weigh everything from produce to currency. Nowadays, their usefulness has become relegated to the laboratory; otherwise, they are antiquated relics that are more decorative than useful in an everyday situation. As a learning project, however, it is educational to show how household objects, like paper products, can be made into a scale model of... well ... a scale.

Things You'll Need

• Poster board Corrugated cardboard Toothpick Paper medicine cups Craft glue Craft knife Small metal weights

Instructions

1. 

   Cut out and construct your base. Using your craft knife, cut from your poster board a large, German-style cross shape, 6 inches wide and 6 inches high. (See the illustration.) In the top and bottom arms of the cross, 1 inch in on both sides, make a 1-1/2inch high slit with your craft knife. Now bend all four arms down, leaving a square platform at the top of the base. Slide the points of the right and left side into the slits you made, so the base will stand upright without falling apart. If need be, add a little glue; but if the slits are deep enough, the base should stand on its own without any further adhesive.

2. Cut out a cradle for the scale. On the platform atop the base of the scales, cut across in two incisions, 1/2 inch apart from each other. Now, cut down and in on both sides, making a "v"-shaped gouge in the top of the base where the platform is. Remove the piece of poster board from the gouge. This is the cradle.

3. Construct the scales. Using your craft knife, cut a piece of corrugated cardboard a little less than 1/2 inch wide and 5 inches long. Insert a toothpick through the middle of the very center of the cardboard strip. Measure the strip to make sure the toothpick is at the absolute center. Make sure the toothpick is secure but can still twist freely. Glue a paper medicine cup to either end of the cardboard strip, being careful to use the exact same amount of glue for both cups.

4. Assemble the scales. Set the scales atop the base, gluing the toothpick securely to the middle of the cradle. The toothpick should not be able to move freely on the base, but should still be able to twist and move freely within the corrugated cardboard scales. Let the toothpick dry completely before use.

5. Place a small object you wish to weigh in the right-hand cup of the scale. The scale will dip from the weight. One at a time, add small metal weights until the scales are sitting even and the cardboard is parallel to the ground. Record the amount of weight you added to the left cup; that is the weight of the object.