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Science Experiments for Kids : Floating Stone experiment

Science Experiments for Kids : Floating Stone experiment
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Science Experiments for Kids : Floating Stone experiment

Set up the classic float or sink science experiment with a twist

When they are not being tested, I guess every single child loves science and loves experiments. Their innate curiosity is being nurtured when they are given the freedom to observe, experiment and predict.With this classic float or sink science experiments kids love to experiment the concept with utmost joy.

Today’s float or sink science experiment has a small twist though. I included a new material!


We used:

  • Pumice Stone
  • Pom Poms
  • Leaves
  • Twigs
  • Stones
  • Pebbles
  • Popcorn
  • Bell
  • Raisins
  • Feathers
  • Gravel

We used a wide variety of materials to see the contrast.

I used a simple round container and filled it up with water and set out the materials pictured above.

We really did not use a observations sheet or any printable. I love this simple printable by Buggy and Buddy!

kids experiments with science

The kids enjoyed first guessing whether the object will float or sink and immediately compared their predictions with the actual results. The popcorn was their favorite.

sink float science experiments

Then I introduced this fun material. A bath pumice “stone”.  The word “stone” kind of set their mind with the “sink” answer. Both the kids felt it and decided that the “stone” will sink just like the other stones and pebbles that went straight to the bottom of the container.

Science for kids

Here is the product link (affiliate link) for the “stone”

But to their surprise this “stone” floats. Yes, it floats for a long time and the kids tried pushing them down to the bottom but it would come back up. However if you observe a large part of the stone is submerged in the water while the top part still is above the surface of the water. But to kids this “magic” stone is floating.

kids science experiments

The pumice stone is a highly porous materials made of volcanic ash. The presence of air cavities makes it really light and it floats for a while. Leaving the stone in the water for a long duration makes the water enter the cavities and it does eventually sink to the bottom.

float or sink experiments for kids

Later I set out 2 jars with labels on them and the kids sorted the materials into the jar for extended observation.

float sink experiments for kids

Thanks for reading

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Science Experiment for Kids Floating stone experiment

More science experiments for kids on our category page

Check out this resourceful e-book packed with many preschool activities with clear pictures and set by step instructions.

Preschool Play Ideas ebook


  1. I did this experiment quickly with my boys to teach them about the different variables – I might just do it again with some of your materials and see what they remembered. Thanks for sharing.


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