In this activity your child makes predictions about what objects will sink or float, tests the objects and then classifies them.

What you’ll need:

  • At least five small objects such as an ice cube, orange, nail, coin, tennis ball, feather and a block of wood
  • Large water container or tub
  • Towels
  • Paper
  • Pen or pencil

Here’s how to do it

Have your child come up with examples of objects that sink and objects that float in water. Discuss why a boat floats and a rock sinks. Make a three-column chart on paper. Label the first column “Objects,” the second column “Predictions” and the third column “Outcomes.”

Display the objects you have collected and write each object in the first column. In the second column have your child predict if the object will sink or float and discuss with him why he made this prediction. Then have your child place each object in the water and observe as it sinks or floats. Write the outcome in the third column of the chart. Discuss the results with your child. What did the objects that sank have in common? How about the objects that floated? At this age your child does not need to understand the concept of buoyancy, but if you would like more information check out Exploratorium: Bouyancy