Throughout our Ocean Exploration, the children have enjoyed spending much time playing at the water table aquarium. Thinking about our discussions of submarines and in observing this play, we decided to engage in a Sink/Float experiment to understand what they knew about the properties of water and objects that come in contact with it. In our research on submarines, the children learned that submarines have large tanks that fill with water, causing them to become heavy and sink. We were curious to see if the children would build any connections to weight of items placed in water and their sink or float outcomes.
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.
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 is when it goes to the bottom.”
“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!”
“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!”
Preschoolers have rapidly developing vocabularies. Day after day they build their semantic knowledge, which is their ability to make meaning of words. Children build their language upon prior knowledge and experiences, therefore, many of the children connected floating to swimming - an activity they are familiar with. Listening to a peer explain what it means for something to float, combined with a child’s existing understanding, enhances their semantic language.
After the children agreed with each other on these definitions, we set up towels and labels to classify each item after it was tested.
After the children agreed with each other on these definitions, we set up towels and labels to classify each item after it was tested.
Before testing each material, we asked the children to state their hypotheses: Will it sink or will it float? As the children made their predictions, they justified whether the object would sink or float depending on its size or weight, often using the word big to imply size as well as weight. However, the children did not always believe that a heavier item would sink.
“The rocks will sink because they’re not very big.”
“These are big enough to float.”
“The pinecones are loose enough to float.”
“These are big enough to float.”
“The pinecones are loose enough to float.”
One child hypothesized that the small size of the rock would cause it to sink quickly. While their predictions of the objects that did sink were often accurate, the children were often unsure whether particular items would float, such as the tree blocks, pinecones and corks.
After each item was tested, the children classified the object by placing it on either the sink towel, or the float towel. Upon finishing the experiment, the students concluded that the weight of an object definitely impacted whether the item would sink or float.
“When they’re too heavy something will sink.”
“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.”
“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.”
These conclusions provided the right start for us to read more about what causes items to float or sink. We read the nonfiction book Tell Me How Ships Float, by Shirley Willis. We learned that if an object is light it will float. Even if the item is big, it can still be light. This explained why our tree blocks floated, even though they are big.
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.
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!”
The children now paid closer attention to the object’s weight in their hands as well as the material of the object. For example, many children noted that the scissors are made of metal and the metal is heavy, causing the scissors to sink.
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.
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.