Looking for a fun preschool science activity to introduce the concepts of sinking and floating? Try the dancing raisins experiment!
Today we’re welcoming Curt Nelson from Make a Kidnection, where he uses stories to make science fun!
What you’ll need
- A bottle of clear soda. (I recommend diet soda in case you make a mess like I did here! At least diet soda won’t be sticky.)
- A box of raisins. You’ll only need 10 or so. The rest make a great snack!
- Optional: A pair of scissors or a knife to remove the label from the soda bottle. Be careful – don’t cut yourself! (You don’t have to remove the label, but it gives a better view of the raisins as they float to the top and sink back to the bottom.)
Added Fun
To make this experiment even more engaging for your preschooler, we’re going to name each raisin before we drop it into the soda. (To be honest, this will also help prevent the soda from overflowing like it did for me in the out-takes at the end of the video. The time you spend naming each raisin prevents you from dumping them in too fast, which is what causes the soda to overflow!)
But why would your kids want to name their raisins? One reason is that kids have great imaginations and love exercising them.
But just to make sure your kids get into the spirit, Bob the Dragon and I shot a short video that sets up a fun back-story about the raisins. Watch this video with your kids:
The Science Behind It
When you drop a raisin in the bottle, it sinks because raisins are denser than soda. But the carbon dioxide bubbles in the soda are much less dense than the soda itself. When the bubbles attach themselves to a raisin, the density of the combined raisin/bubbles is less than the density of the soda, and they float to the top. When they hit the surface, the carbon dioxide is released into the air, and the raisin sinks back down into the soda.
The process repeats itself over and over until there aren’t enough carbon dioxide bubbles to counteract the water-logged raisin’s density.
Explaining the Experiment to Preschoolers
To explain this to preschoolers, we usually use the terms heavier and lighter, rather than denser and less dense. The explanation would focus on raisins being heavier than soda, so they sink. The bubbles are lighter than soda, so they float. And when the bubbles stick to the raisins, they help them float too.
Extend the Learning
Ask your preschooler if he or she can guess any other items that are light and would float in soda. How about items that are heavy and would sink? Then head to the kitchen, pour the soda into a large bowl, and find some items to test. Give the items nicknames based on whether they sank or floated — Gary the Floating Grape, Fred the Floating Ice Cube, Sarah the Sinking Spoon, etc. Be creative, and have fun!
And, of course, celebrate your preschooler’s good work on this experiment by watching the reward video together:
Curt Nelson is a former science teacher and school assembly presenter. Now he (and Bob the Dragon) use stories to make learning science fun at MakeAKidnection.com. Follow along with him on YouTube and Facebook.
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Thanks, Anna, for letting me share with your readers!
So glad to have you here, Curt!
I teach older 3’s, young 4’s. I tell the kids the Earth turns and that’s why we have sunlight and dark. I take kids in bathroom. We turn out light, turn on flashlight (sun) and I hold my globe. I point out where we are, which is marked with a shiny sticker. We start in the ‘sun’. I turn the globe slowly as I say, “The Earth is turning”. Oh, it’s time for us to eat lunch. We are taking a nap now. We are waiting for our parents to pick us up. We are eating dinner. Look, we are almost in the dark, what are we doing? Now we are in the dark, it’s bedtime. These people are in the sunshine now, they are eating breakfast while we sleep.”
I rotate the globe several times as I chat about what we are doing in the sun and dark. We leave, I show the photo of the Earth seen from the moon (taken by astronauts). “What are these white things? (clouds) What are these people doing down here where it’s dark? (sleeping)” We make a craft from a paper plate. Half is painted yellow and they cut out several yellow rays from construction paper and glue them on that side. The other half is painted black and we sprinkle glitter for stars. They cut out a small blue circle and put a sticker representing him/her on the edge of the circle. When the paint dries, I use a paper fastener to put the center of the circle to the center of the paper plate. The circle can rotate around. I show the kids that the circle is ‘turning’ and now it’s daytime (in the yellow part) and Look, It’s night, what are you doing?” I have heard from several parents over the years that their kids play with their plates at bedtime, rotating the circle to place themselves in darkness.
I do this craft every year and invariably so many of my kids smile and enjoy playing with theirs.
My raisins did not float! Why not? I used a new bottle of Sprite and raisins. What did I do wrong. If a preschooler can do it, why can’t I?