Sink or Float: A Science Experiment

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Updated on Mar 26, 2014

Does a paper clip float? Does a sponge sink? Let your child find out! This experiment is simple science fun. Plus, it lets kids practice the Guess and Check Method. First they make predictions, and then they test their predictions through experimentation.

What You Need:

  • Objects for the experiment (small sponge, paper clip, toothpick, marble, plastic spoon, penny, plastic straw, crayon)
  • 2 large pieces of construction paper
  • Newspaper
  • Markers
  • Plastic dishpan
  • Pencil
  • Blank paper
  • Spiral bound notebook
  • Towel

What You Do:

  1. Label one piece of construction paper with the word “Sink” and the other piece with the word “Float.” Gather a bunch of small everyday items, such as the examples listed above, and put them on a table covered with newspaper.
  2. Show your child the objects you’ve collected and tell her that you’re going to conduct an experiment to find out which objects will sink in water and which will float. Make sure she’s clear on what these words mean before you get started, then ask her to predict which of the items will sink and which will float. Hold up each item, one by one, and as your child makes her prediction, place it on the appropriate piece of paper. For example, if she guesses that the penny will float, put it on the construction paper marked Float. Once she has made guesses for all of the items, give her the blank paper and ask her to write each item’s name (or draw its picture if she’s not writing yet), to document her predictions.
  3. Time for testing! Fill the plastic dishpan with water and put one item in at a time. Discuss the result. Then, dry it off and lay it on the appropriate piece of construction paper, either Sink or Float. Once all the items have been tested, give your child the spiral bound notebook and ask her to record the results of her experiment. Wrap the activity up by talking about the results.

The great thing about science is that it can surprise us. Ask your child if any of the objects did something she didn’t expect. Talk about the experiment. Then, clean up your lab space and tuck that notebook away for a future day of experimentation!

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.