Sink Or Float? – Preschool Science Experiments For Kids

by Melanie on December 10, 2014

I’ve been having a tough time gaining the motivation to write back-posts.

The fact is, my blogging just can’t keep up with the amount of stuff we do around here! That’s actually good news. I am always writing inside of my mind, but it’s tricky to find the time to materialize those mental drafts into something I can share.

Between the important work of being a mom, a homekeeper, a wife, a homeschooler, and every other role I play, I simply don’t have a lot of time to spare for writing posts from a time that is not relevant to me right now. So my backlog of posts to be written will trickle out as seems natural, I’m sure. In the meantime, I want to write in real time- because of course, what we did today just feels so much fresher to me!

My son is a lover of science, exploring how things work and becoming almost obsessive in his determination to try to understand. So we’ve been doing a lot of cool science stuff to satisfy his eager curiosity to know more about this world of ours!

Our latest preschool science experiment was this one, called Sink or Float?:

Sink Or Float

The purpose of the experiment was to use hands-on engagement and open discussion to learn about why some items sink and others float.

Sink Or Float? – The Game Plan

  1. Gather different objects to drop into a bucket of water.
  2. Sing and dance to enhance learning experience.
  3. Predict whether the objects will sink or float (form a hypothesis).
  4. Drop the objects into the bucket to test each hypothesis.
  5. Make a chart of the findings.

I talk a lot on this blog about a learning environment being “child-led” and I know that concept can be confusing for some people. It does NOT mean a child doesn’t have guidance and structured routines. I want to use this post to show you how I followed Rocket’s lead, even with a very structured, step-by-step plan in place. I believe that following the child’s lead is the most important thing we can do to ensure that preschool-aged children develop a genuine love of learning, one of the greatest gifts we can hope to instill in them.

The Sink or Float? science experiment invitation looked like this:

Sink Or Float

A big bucket of water, over 2 towels- right smack dab in the middle of our living room. To the side, a container full of items Rocket and I had gathered around the house for testing!

On the living room wall, there was also a Sink/Float chart for us to later report our findings.

Sink Or Float

I include Rocket in as many creative processes as possible during our planning. He enjoys being involved and I like that it gets his cognitive wheels grinding. I asked him what pictures to draw on this chart to represent items that sink and items that float. He chose coins and a rubber ducky, also volunteering to collect these items!

When we were ready to do the science experiment, we gathered around the tub (with Songbird in my baby carrier) and we skipped around in a circle singing this song:

Rocket brought a feather to play!

Will it sink or float away?

Which do YOU think it will be? (Float!)

Let’s drop it in and see!”

We took turns choosing an item (including Songbird) and the purple texts of the song adjusted accordingly (i.e. Mom brought a marble to play. SINK!)

For the verse that states, “Which do YOU think it will be?”, Rocket and I each put in our guesses about whether the items would sink or float. We were both surprised by some of the outcomes!

Sink Or Float

The first several items were floaters!

Sink Or Float

Through this activity, Rocket learned that items that float are filled with more air than items that sink.

Here’s where the child-led comes in. After tossing all the items into the tub, Rocket wanted to get those hands of his immersed in the water. This was not part of the original plan- and it was the most interactive part of the whole thing. As he played, he came to several of his own scientific conclusions without even realizing it! Maria Montessori believed that children are naturally little scientists and based on my own snapshot of parenthood, I’d have to agree with her.

One by one, Rocket pushed the floating items down to the bottom with his hand, held them there for a moment, and let go to watch them float back to the top again. He concluded that those items are still filled with air.

Much of his play was just feeling the sensory experience of his hands surrounded by water. His hands “went swimming” around in the water, catching different items as they moved. He was very happy with his achievement when he moved his hand straight up out of the water with this plastic part still carefully balanced on top:

Sink Or Float

His sister was also quite impressed! He moved around the air with this item on the back of his hand, deeply concentrating on making sure it didn’t fall.

Next, Rocket tried to “stir” this toy we call “crash balls” in the water. The toy is composed of two wooden balls attached by sting to a third, smaller ball that is meant to be held. I loved that he was working on this motion because for him to get in the rhythm of stirring in harmony with the water without making a splash, he had to slow down. Great practice for patience!

Sink Or Float

Songbird poking him as he played also was great practice for patience!

Speaking of Songbird…

At this point, she had had enough. Have I mentioned that she ALWAYS wants to do what everyone else is doing? She was entranced by her brother’s play up until now- her breaking point- and she was FED UP. She was hollering, screaming bloody murder and she was absolutely furious that she was sitting in the bouncer seat while her big brother was having all the fun.

So I let her have a go at it!

While Rocket played busily on one side:

Sink Or Float

Songbird was doing this on the other side:

Sink Or Float

With close supervision, sensory experiences like this are very enriching for babies under 1! Never leave a baby unattended around standing water.

Another cool thing Rocket did as they played together- he used the yellow cup (which was an accessory for my breast pump) as a boat for all the other items in the tub. He tested each item that had sunk to the bottom of the tub and learned that every single one of them could float using the yellow cup as a boat! Then, he turned it all into small world play and narrated for the objects as they boated to and fro in the pond.

Sink Or Float

When everyone was ready for phase 2, we toweled off the items one by one and brought them to the Sink/Float chart. I asked him if he would rather write the names of each item on the chart or tape them directly on. He wanted to tape them!

And had I realized that Rocket would want to make sure the Float items were taped above the water line, I would have drawn the water much lower! How could I argue with that logic? The chart essentially became a “play scene” for him and he moved the items either gracefully above the water on the Float side or descending abruptly to the bottom of the Sink side!

Sink Or Float

Everything is an imaginative play world with Rocket and that’s how he learns best! I don’t scold him when things don’t go as I’d originally intended. I work with it and usually it works out way better than anything I’d planned! The blue lines on the “Sink” side were the markers sinking. He colored on the chart like this for a significant amount of time (in kid world). He also traced his hand on the bottom, after dragging it down the paper to properly sink. His writing/drawing is a “living” process. I love what his creative mind brings to the table of all our projects and activities!

I was going to leave the chart up for a few days for him to revisit. Instead, some time after we were done, the Sink/Float chart fell off the wall due to the weight of all the items. I guess you can say that it sank. Haha!

This activity was a lot of fun for both of my children, 8 months old and 3 years old. I have a feeling that if presented in an age-appropriate way that molds flexibly with the learning styles of the individual children, this science experiment would be appealing for kids of all ages!

Browse these inspirational blogs for more fun ideas to do at home with your kids:


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