Kids are natural scientists. They’re constantly making observations about the world around them, testing hypotheses, and drawing conclusions based on data. At home, we’re able to let scientific exploration to unfold naturally—there’s no rush, no grades, no test.
That being said, sometimes it is nice to set up opportunities for kids to be more structured with their science; things that’ll pique your kid’s interest and expand their vocabulary. That’s where this kitchen science project comes in. It’s quick, entertaining, and lets you throw out a few scientific terms to show the kids that you still rock science, just like them.
First, Some Pro-Terms
- Volume is the amount of space an object occupies.
- Mass is a fancy word for weight (basically it’s the number of atoms in an object).
- Density is a measure that tells us whether something will sink or float. You determine it by dividing an object’s mass by its volume.
Now, Let’s Dance!
Fill a glass 3/4 of the way full with soda. Observe it. Do you see bubbles? Those little gas globes are filled with Carbon Dioxide, or CO2.
Now drop a raisin into the glass. What do you notice? At first they sink, but then something changes. Look at the raisin covered in bubbles. The gas bubbles have increased the raisins’ volume. Up, up, up it goes! Once the raisin reaches the top, it sinks. Then it floats again. What’s going on?
What we’re seeing in this experiment is how an object’s density can change. At first the raisin sinks because its density is greater than soda. Then the bubbles increase the raisin’s volume, helping it displace more water and voila! It’s density is now less than soda and it floats to the top. Once it reaches the top, the gas bubbles pop leaving the raisin, and the raisin’s volume decreases. That’s when the raisin falls back down and the cycle starts all over again.
The raisins will dance until they run out of gas. Literally.
Take it further
- Draw a picture of a raisin. Trace its outline in black. Then draw bubbles on your raisin. Trace the new outline. It’s bigger, yeah? The larger outline shows the increase in volume. The added bubbles help the raisin take up more space.
- Brainstorm a list of objects you think might sink or float in soda. Go ahead and test them out.
- Test out how mass affects density with this penny boat challenge.