Sink or Float: A Science Experiment

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Updated on Mar 25, 2016

Do toothpicks float? Does a plastic spoon sink? Find out which types of objects float and sink with this exciting science project. Your kids will get to practice making hypotheses about what they think will happen to each object and then test whether they are right through experimentation.

What You Need:

  • Plastic dishpan
  • 5-7 Small household items. Examples include a paper clip, plastic spoon, coin, toothpick and sponge.
  • Notebook or binder paper
  • Newspapers
  • Towel
  • Marker or Pen
  • 2 sheets of construction paper

What You Do:

  1. To set up for the project, pace the newspaper on a table. Write the word “Sink” on one sheet of construction paper and the word “Float” on the other. and the other piece with the word “Float.” Put the objects on the newspaper.
  2. Review the meaning of the words “sink” and “float” with your child. Explain that we are going to do an experiment to see which of the objects sink down when they are placed into water and which ones float.
  3. Ask your child to guess which objects will sink and which one will float. Place each object next to the appropriate sheet of construction paper based on the prediction.
  4. Divide a piece of binder paper into thirds vertically. Ask your child to draw each object on a piece of binder paper and write her prediction next to each object in the middle column of the paper (sink or float). On the right column of the paper, add a label that says “Result”.
  5. Next, add some water into the plastic dishpan. Choose one of the objects and place it into the water. Observe whether it sinks or floats and record the result on the binder paper next to each prediction. Repeat this for each of the remaining objects.
  6. Have your child compare the prediction for each object to the result. If any of them do not match, discuss why your child thought about those objects and what he learned. Your child should now have a better understanding of what types of objects sink and float!
Latrenda Knighten has spent 19 years teaching in a variety of elementary school classrooms, from kindergarten through fifth grade. For nine of those years, she taught kindergarten. She also served as an elementary school math and science specialist. She lives in Baton Rouge, Louisiana.