Guest post by Cindy Hoisington, with thanks to Karen Worth and other dear colleagues for their inspiration

Welcome guest blogger Cindy Hoisington, an early childhood science educator at Education Development Center Inc. (EDC) in Waltham, Massachusetts. A preschool teacher for many years, Cindy now works with early childhood teachers, coaches, and administrators in various settings to support young children’s STEM learning. Cindy loves to share stories about aha! teaching moments with other educators and believes that a story can be a valuable teaching and learning tool, especially when it captures a shared experience and stimulates reflection and discussion. In this post Cindy shares a story from her preschool teaching days about how she came to appreciate the power of children’s science ideas during a sinking and floating unit.

As an early childhood teacher I loved doing science with preschoolers but sometimes their crazy ideas seemed to get in the way of all the interesting science concepts I wanted to teach them such as: shadows are made when an object blocks the light; animals are adapted to habitats that meet their needs; and the properties of building materials influence how they can be used in structures. I thought that children’s ideas, such as shadows are living things because they run and jump like I do; birds are not animals because they don’t have fur; and only tall blocks can make tall buildings, were adorable and funny but I didn’t have a clue what to do with them. I didn’t want to inhibit children’s explorations with constant corrections and I worried that providing overly simplistic explanations would further confuse them. Lucky for me, several years into my teaching, I had the opportunity to work with an early childhood science mentor who suggested that I rethink my role in supporting children’s science learning and focus on three primary and mutually reinforcing science-teaching strategies: Get ALL of the children’s science ideas out on the table, Provide opportunities for children to investigate their ideas, Facilitate children’s reflection on the evidence.

Sinking and Floating Explorations

I had always begun a sinking and floating unit by holding up some familiar objects like a marble, a rock, a crayon, and a block and asking children to predict whether the objects would sink or float in water. I would chart children’s predictions, and we would test the objects and record the results in small groups. Later we would compare our predictions to what actually happened.  This time I was determined to dig more deeply into children’s science ideas and to extend their explorations over several weeks rather than several days.

I knew that the focal science concept in sinking and floating- density- was abstract for young children. I also knew that an explanation of density as a relationship between weight and size would be meaningless and do little to promote their thinking. I decided that my goal would be for children to investigate all the observable properties of objects, some of which might influence whether the objects sank or floated. I also wanted to promote children’s inquiry and their abilities to raise questions, plan and follow through on investigations, collect and record data, and especially, to rethink their current ideas based on new evidence.

 Get ALL of the Children’s Science Ideas out on the Table

I began our sinking and floating unit by asking children to make predictions as I always had. But this time I also asked them to share their ideas about why they thought certain items would sink or float. What properties (size, weight, shape, texture, material kind) did they think made a difference?  And why did they think so? When and where had they seen things floating? Or sinking? What did those objects look like? And feel like? By probing their thinking in this way I uncovered children’s ideas that I was previously unaware of including “round things float because my brother’s soccer ball floated in the pool;”  “green things float because leaves float in puddles“ “heavy things float because my dad’s boat floats;” and “small things sink because they’re not strong enough to swim without swimmies. “

I also encouraged children to share their predictions nonverbally. I invited them to place items on sink and float trays; to “stick” photos of the objects to a chart; and to draw their predictions on paper. Drawing enabled children to express their thinking more precisely than they could verbally since they could draw the objects suspended in the water at different levels as well as at the surface or the bottom of the tub. Finally I closely observed and recorded children’s behavior at the water table.  This enabled me to realize for example, that some children thought they could make objects sink or float if they just held them under the water, or at the surface, long enough! As children shared their ideas verbally in conversations, and nonverbally through their predictions, drawings, and behavior I collected and recorded documentation (observation notes, charts, photos, drawings) that revealed their ideas.

 Provide Many Opportunities for Children to Investigate their Ideas

The next thing I did was to bring children’s ideas to the large group so we could think and talk about them together, using all of our documentation as evidence of their thinking. One day for example we talked about one child’s idea that all round things float. Who agrees with the idea that all round things float? Why do you think so? Does anyone have a different idea? What kinds of round things have you seen floating? Sinking? Have you seen round things do anything else in water? I encouraged children with different ideas to talk directly with one another, sharing their evidence: I think round things float because…. and I think round things sink because… … As a group, we planned how we would investigate these ideas and began collecting round things to test in the water. I made sure to collect round things that sank, floated, and stayed suspended (some limes!) in water. In small groups we tested the items, made multiple observations, and collected and recorded data by taking photos, drawing pictures of the objects in the water, charting what happened, and placing objects in “it sank” and “it floated” piles.

 Facilitate Children’s Reflection on the Evidence from their Explorations

After our inve
stigations we came together and talked about what children had done and observed. I scaffolded our conversations using the objects themselves, the data we had collected, and our prediction charts and other documentation. First we discussed questions like: What happened when we put the round objects in water? Did each object always do the same thing? Did it make a difference if you dropped it from up high or down low? What happened when you held it at the surface or at the bottom of the tub? Which ones floated and which ones sank? How did what happened compare to what we predicted? Were there any surprises? What surprised us and why? Since I wanted to promote children’s willingness to share their ideas in the future, I was careful not to use words like “right” or “wrong” when we talked about their previous ideas and predictions.

All of the children now enthusiastically agreed that some round things floated and some round things sank and, as a result of the evidence, they were beginning to develop new ideas.  We decided to look for other differences between objects that sank and the ones that floated besides “roundness”. We considered questions like: Which one feels heavier or lighter? What material do you think it’s made of? Is the texture smooth or rough? Do you think it has air inside it?  What makes you think so? We made a list of what we noticed about round objects that sank (heavy, metal, spikey, squishy) objects that floated (light, plastic, has holes in it, smooth), and objects that stayed suspended in water (has holes in it and water inside, flat, floaty).  Next we generated some new ideas: maybe plastic floats because it’s lighter than metal; maybe things with holes float because air gets in and holds them up; maybe they will sink if water gets in the holes and some new questions: Does plastic always float and metal always sink? Aren’t some boats made of metal? What about wood? Do the number of holes make a difference? Most of the objects we tested were small….what about bigger objects?.  By listening closely it became clear to me that children had ruled out shape as a factor in sinking and floating and were now thinking about material kind, size, and weight (air or water inside the wiffle ball). Although I knew we weren’t done with shape yet (I would extend their thinking about shape by inviting them to make and test clay boats the following week) I stuck with their current line of thinking as we planned our next investigations. Maybe we would try floating and sinking some plastic and metal things of different shapes; a really big plastic block and a tiny plastic block; or wiffle balls with the holes plugged up with tape. These suggestions would drive another cycle of exploration and reflection, and children’s ideas about sinking and floating, and about how to investigate it, would continue to get increasingly specific and sophisticated over time.

Final Thoughts

My work with an early childhood science mentor helped me shift my focus from where I wanted children’s thinking to be to where it already was. Drawing out and acknowledging children’s current ideas made them available for investigation and empowered children to construct new knowledge because they had tested their ideas, and collected and analyzed the evidence. These experiences also helped me to address learning standards in a more in-depth way than I had before. In the sinking and floating explorations for example, children were learning about the properties of solids including size, weight, shape, texture, and material kind and they were being introduced to the concept of density at a foundational level. Children were also experiencing high-level inquiry. Not only were they asking questions, making predictions, and following through on investigations, they were analyzing and interpreting data in order to generate ideas and construct explanations. They were also being introduced to the nature of science and the concept that theories are formulated based on observable and testable evidence. Finally, they were developing scientific habits of mind including the ability to take risks with ideas and a willingness to be flexible with their ideas when the evidence no longer supported them.  

In my current work with teachers and other educators I sometimes tell stories like this to promote their thinking about the power of children’s ideas, and about responsive and research-based science teaching (I like sinking and floating stories because they are easy for all early childhood teachers to relate to, but children’s ideas can be the focus of any science topic). Through these stories I also aim to encourage teachers to take advantage of their own classrooms, their own students, and whenever possible mentors, coaches, and colleagues, to keep driving their own professional development forward. Never stop having aha! experiences and never stop sharing them with other teachers and educators!  You never know who will be listening!