Math in Our World: Sink or Float?

Makayla sits in a bathtub full of water and soap bubbles and bath toys. Some of the toys include rubber ducks, a boat, and a turtle. Someone is tossing a beach ball into the bathtub.

What do you notice? What do you see in this picture? Share your ideas with a friend or family member.

In this picture, we see Makayla’s bath toys floating on top of the water. Some toys and objects float and some sink. Do you think any of her toys sunk to the bottom of the tub?

Here’s a math experiment for you: Gather 10–20  small toys, items from outside, or things from the kitchen. Ask a grown-up to help you fill up a sink, the bathtub, or a container with water. Count how many of your items sink and how many float. Were you surprised by any of the items?

  • Decide how many items you want to use in your experiment. Choose either 10 items or 20 items from around your home.
  • With a grown-up’s help, make a chart that says “sink” on one side and “float” on the other. Make predictions about whether each of your items will sink or float.
  • Put each item in the water and watch to see if it sinks or floats.
  • Sort the items on your chart.
  • Count how many items are in each category.

Tell someone about your work. Ask them what other items they’d like to try out in the water.