Balancing Points

Ages 8-10
(This activity can be done with younger kids but they may need some assistance with putting their mobiles together depending on the level of fine motor skills.)
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Print Student Activity Sheet

What You Need

• A Balancing Points activity sheet for each student [download PDF]
• Objects for a mobile (We recommend cutting different weight shapes out of thin cardboard or thick paper ahead of time. If time allows, have kids decorate them prior to making mobiles.)
• Hangers (one for each mobile)
• A hole puncher
• String

Background

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.

Activity Instructions

Set-Up

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.

Activity

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.

Related Activities

Have kids watch Circus by Alex, Sarah and Sasha, from Dragonfly TV, to learn about balance in another context.

Learning Goals

Benchmarks for Science Literacy

There is no perfect design. Designs that are best in one respect (safety or ease of use, for example) may be inferior in other ways (cost or appearance). Usually some features must be sacrificed to get others. How such trade-offs are received depends upon which features are emphasized and which are down-played. — 3B The Nature of Technology: Design and Systems (3-5) #1

In something that consists of many parts, the parts usually influence one another. —11A Common Themes: Systems (3-5) #1

National Science Education Standards

The position of an object can be described by locating it relative to another object or the background. — Physical Science: Position and motion of objects (K-4) #1

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