Sink and Float: Predictions

Following a full group lesson on what it means to “sink” and “float” and be “suspended”, the children began to work in small groups at the science center.

A variety of objects were available such as rocks of different sizes, assorted wooden blocks, plastic blocks, feathers, rubber bands, candles, empty bottles, full bottles, an empty aluminum can, and so forth. I had photographed the objects and copied them to sheets, which were available for the children’s predictions.

The challenge was to examine the objects and take a guess at whether it would float or sink. Children could easily check off boxes next to the object’s picture to make their choice. This is also a great example of introducing data collection in class. Mark your paper, test it out. What was the result?

Azy’on says, I was right!

I noticed some children were predicting randomly at first. After a little bit of experience, they began to use reasoning. I wanted to find out what they were thinking. I asked one of the girls, I noticed you marked that the little rock would float. Why do you think so?  Her response, I think it will float because the big rock sinks. It sinks because it is heavy. The little rock is not heavy so it will float. I expected her to be disappointed after she tested her theory but, Nope, it sinks too. I guess all rocks sink was her reaction as she moved on to try the cans. She showed me she has learned to generalize information.


The PEEP video Making Things Sink and Float is great to show the children AFTER their exploration—that way their predictions aren’t biased by the video.  Their own experiences combined with what they see on the video can extend their reflective discussion. What’s the same about the way the children in the video learned about sinking and floating? How was their experience different from ours? If you were able to go there and work with those children what would you try? What would you say to them?

In addition to sink and float activities, the children had the opportunity to explore tubes, which I had half-filled with colored water and then closed at both ends. I encouraged them to hold the tubes vertically, horizontally, and in any way they wanted. Observe closely. What happens?

They answered: The air goes up; The water goes down; When I make a circle the water stays at the bottom.  What content they are learning? Water seeks its own level!

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0 Responses to Sink and Float: Predictions

  1. laura says:

    I love how a child will have one theory then when they test the theory and find out they were wrong they come up with a new one. Great activities and investigations you have done with the children. They have such wonderful answers to your questions.

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