What Floats?
Materials:
- Metal Nail
- Piece of Paper
- Glass Bottle
- Plastic Bottle
- Plastic Comb
- Rock
- Flower Petal or Leaf
- Large tub of water, filled
Instructions:
1. Discuss the concept of density and buoyancy with your child.
2. Start testing the buoyancy of the different materials, seeing which ones float and which ones don't.
3. After the successful floating or sinking of each material, ask your child why this object floated and why the other one sank. They should be able to tell you it is because the object has a greater density than water or that it isn't able to displace enough water to be pushed upwards.
This activity is really quick and simple, but can take a while for some children to understand. If your child does understand the concepts of density and buoyancy well, though, you can teach them how to divide with a calculator and start asking them to compute for the density of an object. Give them the known density of water, and your child will be able to predict whether or not something will float.
Next Article: Mixtures
