Sink or Float Experiment with Water {Printable for Kids}

Do your kids love to experiment with water?  Check out this great idea for some hands on learning in water as they discover if items will sink or float.  Kids Activities Blog is not responsible if your kiddos get a little wet with this one!

Kids love this sink or float experiment with water

Experiment with Water

Water.  There’s something about water that draws young children into a learning activity.  After watching a video on different types of boats, Bear {4 years} wanted to do an experiment on floating.  I gave him a small plastic tub and sent him off to search the house for small items that he wanted to use.  I encouraged him to find objects that he thought would both float and sink.

Before dropping them in the water, I asked him to predict whether or not the item would float or sink.  As with any experiment, some theories were correct, some were not.  For example, in the picture above, we were both surprised that the larger brick floated while the smaller one sank.  We both thought it would be the opposite.  This gave us a chance to talk about buoyancy and how the larger one likely had more space in the underside to keep it afloat.  This theory also proved true when several Lego’s were attached together.  The air trapped between the bricks allowed them to float, even though they were heavy.

sink float experiment

Sink or Float

Like many experiments, repetition is key to finding solid results.  This is shown by the fact that Bear went through the items two more times; all the while adding more items in.

Sink or float?  Let your kids discover on their own with this great experiment with water

Will It Sink or Float 

If you want to try a sink or float experiment with your child or classroom, here is a printable that you can use to record the items,  your predictions, and the outcomes of the experiment.  (Just right click on the image and select “Save picture as”)

Here's an easy printable for kids to use to track predictions and results about whether items will sink or float

Not only is the activity great for practicing critical thinking, it’s fun and allows an opportunity for families to spend time together.  When we did this project, it was myself, Bear, and Pip (17 years).  Even she was getting into it.  It could be turned into a family challenge to see who has the most correct predictions.

More Kids Activities

We hope you and your child enjoy this experiment with water.  Do you have any other ideas for teaching about how items sink or float?  For more great water experiments, take a plunge into these ideas:


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About Andie Jaye

Andie Jaye is a former preschool teacher turned SAHM of two kiddos. Her blog, Crayon Freckles, is an eclectic mix of play, art, and learning activities. Mingled in are her perspectives on being a crunchy momma, having a long-haired hippy boy and using follow-your-gut parenting. See more of Andie on Crayon Freckles' Facebook page, on Pinterest or on her parenting teens site Why Does My Teen?