Does it sink or float?
A simple, hands-on STEM experiment with water and everyday objects
This classic sink or float experiment is a playful way to introduce kids to scientific thinking. Whether you’re using the kitchen sink, a tray of water, a bath, a bottle, the beach, or even puddles on a rainy day, the fun is in making predictions, testing, and observing what happens.
It’s wonderfully easy to set up and can lead to big, curious conversations. Plus, it’s a great excuse to let kids splash around while learning!
Materials
Prep
Gather a mix of objects from around the house, garden, or beach that are safe to get wet.
Play
Step 1:
Fill your container with water.
Step 2:
Choose an object and ask, "Do you think it will sink or float?"
Step 3:
Place the object in the water and observe what happens.
Step 4:
Sort the objects into sinkers and floaters and keep testing more!
Extend
Test in salt water: Mix salt into the water to see if it changes results.
Engineering challenge: Can you build a boat or raft that floats using recycled materials?
Sensory play: Add some cups, spoons and other toys for an open-ended session of water play
