Mobiles are a great way to learn about balance and the center of gravity. Make a simple mobile from some household items and see if you can balance it.
- milkshake straws
- beads with large center holes
- large plastic sewing needle
- cardstock and shape template (download pdf)
- Pierce the center of each straw with a toothpick.
- Cut a slit on both ends of each straw.
- Thread your string onto a plastic needle. Tie a knot the end of the string.
- Thread three or four beads onto the string. Add a straw. Repeat. Once your mobile has been threaded, tie a knot at the top.
- Cut out your cardstock shapes.
- Add a shape to each end of each straw to balance.
THE SCIENCE BEHIND THIS PROJECT
Straw Mobiles demonstrate the concept of the center of gravity. The center of gravity or mass is the point at which an object is perfectly in balance. While adding the paper shapes, notice what happens when you add a shape to only one end of the straw. The straw will be off balance, even with something as light as paper. Try adding different shapes to the ends of a straw and see what happens. You will need to have shapes of the same size on each end of the straw to properly balance it.