Pumpkin Science Experiment: Sink or Float?

Little ones love to make predictions and ask questions! This Pumpkin Science Experiment has always been a big hit back when I was a teacher working with little ones. Now I am trying it with my son in homeschool. Actually, we veered away from our normal Zoology science studies, I just couldn’t resist since I just bought some pumpkins and this is my favorite Fall experiment. It’s all learning, right!

This activity will challenge your child to make predictions, graphing, discover density, and buoyancy with… pumpkins! While you’re at it have them guess if other items will float or sink. Have them collect things around the house and have them make predictions and then test them.

You can even use this at a Halloween party or carnival and have kids guess what items float. I love all the possibilities for some educational fun!

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Do Pumpkins Sink or Float? Science Experiment

Have your child ask different people what they think and graph it? Use this free printable for graphing, just click here to download: pumpkin science experiment. This will set the stage and create anticipation for this experiment, as they will be dying to know what really happens.

Supplies:

Pumpkins (different sizes)
bucket of water (large enough for your pumpkins)
Scientific Method worksheet (optional)

If you have kids you are in 1st grade on up, they can fill out this Scientific Method worksheet before you start the experiment: Science Experiment Printable.

1. Ask your child if he thinks the pumpkin will float or sink? If you’re using this for the classroom you can collectively graph your answers. Why does he think that? Some might say that the big pumpkins will sink but the little ones will float.

2. Place the pumpkins in the water one at a time and talk about the results.

3. Discuss with your child why the pumpkins floated regardless of size. (The answer? Pumpkins are hollow objects, and there is enough air trapped in the center of the pumpkin that it floats.) The huge pumpkins will bob in the water with part of the pumpkin in the water.

Science can be fun! Without even knowing your child is practicing the crucial science skills of prediction, experimentation and reasoning. Density is what makes something sink or float, not weight. It’s about how the weight is spread out. So the more hallow space makes something less dense and that makes it easier to float.