Balance is a fun concept to play with. By constructing models, your group will learn that putting heavier objects closer to the center and lighter objects farther from the center is one way to find a balance.
Similar to finding balance between two people on a seesaw, hanging two objects on a hanger demonstrates that the heavier object needs to be closer to the center, the lighter object farther away. This idea could be used throughout the making of a mobile, with a hanger or other materials. The hook from which a hanger hangs is the balancing point of the mobile. As objects are added, the balance may change, but the balancing point will remain the same. Adding more tiers to a mobile will put more mass below the balancing point, but playing with the placement of objects is what will balance out the mobile in the end.
Before you present the activity to the kids, punch holes in two paper shapes of different weights, tie a length of string to each one, and tie the other end of each to the hanger. Hold it up for your group to observe.
Ask your kids: “Does this mobile seem balanced? How could we fix it?”
Ask kids: “Have you ever seesawed with someone who was heavier or lighter than you? Was there a way to make your weights seem even?” (Most kids have probably experienced a heavier person sitting closer to the fulcrum of a seesaw so that the weights seemed equalized enough for successful seesawing. Make a comparison between the mobile and the seesaw scenario.)
Now kids can do the activity on their own or with a partner. Depending on the age of your kids, partners may work better if the kids have trouble putting the mobiles together by themselves.
Give each kid a Balancing Points activity sheet and pencil and point them toward the student web page.
Also provide the supplies to make a mobile: hanger, string, cardboard to cut shapes from (or other items for hanging), and sticks.
If someone has an interesting dilemma, or example of balance, you may want to hold it up and discuss it with your group. Try having kids experiment with balancing light objects and heavy ones. You also could have a competition to see which kid can add the most objects to his/her mobile and still keep it in balance.
Have you ever tried to make a mobile? It can be tricky if you don't pay attention to balance. The best mobiles have parts that are balanced or that move freely. If the parts aren't balanced, you can end up with a tangled mess, not a mobile! That's no fun! Want to learn the secrets of making one that balances just "right"?