Will it sink or float? That is a question kids love to experiment with to answer, whether it be toy blocks, boats, or just odds and ends from around the house, kids everywhere enjoy putting things in water to see if they will sink or float. (Related Post: Plastic Egg Submarines)
This week we decided to answer the question: Will the pumpkin sink or float?
We took our pumpkin to the pond for the first part of our experiment. You could also use a large basin of water, the kitchen sink, or the bathtub, depending on the size of your pumpkin.
Before tossing in the pumpkin, the kids carefully examined it. They talked about its shape, size, and weight.
Then I asked each of them to form a hypothesis. Did they think the pumpkin would sink or would it float?
They both decided the pumpkin would sink. It was a pretty heavy little pumpkin, after all!
We gently placed the pumpkin into the water. (Read that as my daughter had fun tossing that little squash into the pond and seeing the big splash it made.)
Both kids were surprised by the results.
The pumpkin floats!
Now that we had one question answered, it was time to get our hands messy and investigate further.
Just why did the pumpkin float? And, would the seeds float or would they sink?
We cut open our pumpkin to check out its insides.
It was easy to observe that the pumpkin was not completely solid inside. The pulp and pumpkin seeds had plenty of space around them full of air.
We decided this helped our little pumpkin stay afloat.
And the insides?
Our pumpkin seeds, and the pulp, floated when put in a small bowl of water.
Want to take it further?
In order for an object to float (like the pumpkin or its seeds), it has to displace enough water to be equal in weight to the object.
Pumpkin seeds are flat, and they displace enough water to float.
Try the experiment with an apple instead. If you’ve ever been bobbing for apples before, you know the apple will float. But what about the seeds?
They will actually sink because their round shape does not displace enough water.
Want to experiment more with sinking and floating?
And for more pumpkin fun: