You will need:
1. Fill your bowl or tub with enough water to cover the biggest produce. Examine your items and compare their sizes, shapes and weights. Do some feel solid or hollow? Which ones do you think will sink or float in water?
2. Test your predictions by placing each item in the tub to see if it sinks or floats.
3. Does removing a rind or peel change the buoyancy?
4. Does ripeness affect how items sink or float?
5. What happens when you cut the food into smaller pieces?
One that has a moving center of gravity. Here’s how to create one at home.
You will need two balloons and some water.
1. Pour a little bit of water into a balloon and tie the neck.
2. Squeeze and push the small water-filled balloon into the empty balloon.
3. Blow into the outside balloon and tie the neck so that the little water-filled balloon is inside the outer inflated balloon.
4. Now, toss the balloon to someone else, or throw the balloon up in the air and catch it. What happens?
(A "Try This at Home" from Explora's newsletter, Explorations)
How would you design and build a structure that can transfer a small ball between two points bridging a 6-foot gap?
There are challenges to this task: you can use less but not more of the suggested materials; the ball cannot be thrown; and once the ball is in motion, the set-up and the ball cannot be touched.
(A "Try This at Home" engineering challenge using string paper clips, move small balls from Explora's newsletter, Explorations, Spring 2009)
To create the top's disk, make a small hole in the center of a disk. You can then push a pencil or another spindle-like object partway through this hole for a snug fit. If the hole is too big, wrap rubber bands around the spindle or reinforce it with tape so the disk stays on the spindle. Now take it for a spin!
A "Try This at Home" build-your-own-spinning-tops project from Explora's newsletter, Explorations, Spring 2010