Make a Bungee Scale

By Sue Bradford Edwards and Pam Schiller and Lynne Peterson

Because your child’s favorite plush cat is bigger than a small brick, she probably thinks Kitty weighs more. But weight is more complex than the size of an object. Introduce the concept of weight to your child by making a fun and easy-to-use bungee scale! This project will enhance your child's understanding of weight and will even provide her will a foundation for understanding more complex scientific principles such as density and gravity.

What You Need:

• A large plush toy (we used a kitty)
• A dense object (we used a brick)
• A variety of other objects, some of which are deceptively heavy or light
• Bungee cord
• Bucket
• Roll of paper
• Marker

What You Do:

1. Find a rod with a wall behind it to build your scale. You can use a rod in a closet or perhaps a rod on a rolling rack set near a wall.
2. Fasten the bungee cord to the bucket. You may need to wrap the bungee cord around the bucket’s handle and secure the fastener to the cord itself.
3. Hang this from the rod.
4. Place the objects that you plan to weigh near the scale. You will need a large plush toy (kitty), a smaller dense object (brick), and a variety of other objects.
5. Don’t let your child pick anything up yet, but explain to her that she is going to help you arrange the objects by how much they weigh. Begin with Kitty and the brick. Which does she think is heavier?  She will probably say her toy since it is bigger. Set them back down with the object she thinks is lighter to the left.
6. Now show her another one of the objects. Does she think it is lighter than Kitty? Heavier than the brick? Or somewhere in the middle. Arrange the objects in order, lightest to heaviest.
7. Take a photo of the row of objects so that you can compare this line up with the results you get when you weigh each object.
8. Explain that you are going to weigh things using your scale. The heavier each object is, the farther down the bucket will go. 
9. Have her put the plush toy in the bucket. How far does the bucket drop? Draw a mark even with the top of the bucket. Label the mark – Kitty.
10. Now weigh the brick. Again, make a mark at the top of the bucket and label the mark – Brick. It is lower than the mark for the Kitty because the brick weighs more.
11. Continue until you have weighed each object and marked it on the paper. Arrange the objects by their actual weight. How does this line up compare to the lineup in the photo?

As an add-on to this activity, encourage your child to arrange the objects on the ground in order of their weight.

Adapted with permission from "Count On Math: Activities for Small Hands and Lively Minds." Copyright 1997 by Pam Schiller and Lynne Peterson. Used with permission of Gryphon House, Inc., Maryland. All Rights Reserved.