We decided to use natural materials that the children were familiar with in our first experiment. We collected rocks, seashells, sea coral, tree blocks, pine cones, and corks. In small groups, we worked with children in the TinkerLab. We began by discussing the definitions of sink and float.
“Sink means it goes down.”
“Float is you’re going up.”
“Floating is coming up on the top of the surface.”
“When I go swimming I float!”
After the children agreed with each other on these definitions, we set up towels and labels to classify each item after it was tested.
“These are big enough to float.”
“The pinecones are loose enough to float.”
“Stuff that belongs in the ocean will sink, too, just like it does in the water table.”
“If it doesn’t float, it will sink.”
In reading, we also discussed the properties of air in relation to an object’s ability to float. When something is filled with air, it can float. Many children shared stories about using floaties in the water to help them float. They were able to make the connection that because floaties are filled up with air, this causes them to float.
When something comes in contact with the water, the water will try to push it back up. We learned that this push is called the water’s upthrust. Light objects are pushed back to the surface by an object’s upthrust. If the item is too heavy, the upthrust will not be strong enough to push it up, causing it to sink.
After reading the story, the children suggested we experiment with different items from our classroom, such as paper, Legos, scissors, Magna-Tiles, and balls. With strong background knowledge under our belts we were ready for round two.
In the second round of experiments, the children applied their newly learned vocabulary in their predictions.
“The paper is light. It will float.”
“I’m trying to push it down. The upthrust pushes it up!”
There were still items, however, in which they struggled to apply these newly learned rules. For example, we tested three different balls: a whiffle ball, a medicine ball, and a soccer ball. While the children relied on the weight of the whiffle and medicine ball to make their predictions, they struggled to look past the size of the soccer ball, predicting that because it was so big it would sink. Preschool children are perception bound thinkers, and often cannot focus on more than one aspect of a problem. They could examine the size of the soccer ball, yet looked past the importance of it's weight. This is because they cannot simultaneously focus on both size and weight.
Preschool children learn through observing and acting on their environment. Through these experiments they were able to make meaning from their experiences by describing, talking, and thinking about what happened. In turn they generated explanations and communicated conclusions about their world.