Sink or Float?

This lesson is designed for children 2-6 and is one of the first science lessons you can introduce to your child. Allowing them to explore the concept of sink and float while working on cause and effect, observation, data gathering, critical thinking, etc. This also introduces the scientific method, developing a hypothesis, designing a test, running the test, analyzing. 

What you need for this lesson: 

  • Large container with water
  • Towel for clean up
  • Objects from around the house:
    • Sink: pennies, rocks, toy cars….
    • Float: Lego, feather, pencil….

How to introduce this lesson: 

  1. Fill the container with water
  2. Have your child walk around the house and find objects they think will fit in the container. (you can choose to gather the objects before the lesson and have it all ready for your child if you would like)
  3. When you and your child are sitting you can ask your child to choose one of the objects. Then ask “ does this sink or float?” 
  4. Have the child drop the object in the water and observe. Have the child tell you if it sinks or floats. If this is new vocabulary you can give your child the words. “The toy car sinks.”  
  5. You can choose how your child will gather the data. If they are younger you can have them take out the object and place it on the appropriate side. Or you can have your child check off, sink or float with a pencil or crayon. 
  6. Repeat the exercise with every item. 


All you will need to set this lesson is a big container that you can fill with water. (a bowl, a bucket, a bin..) As part of the lesson you can ask your child to go around the house and collect items they feel will fit in the container you have chosen. (examples: toy cars, crayons, rocks, pennies, pencils, lego, grape, etc.) 

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Published by Christelle

Former Montessori School Teacher and Child Life Specialist. Specialize in early childhood education.

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