Simple Science Experiment: The Dancing Raisins
Not enough time on your hands to think of scientific experiments your child can do? Think that most science requires lots of shopping? Most of what you need to conduct meaningful experiments is right in your kitchen. However, knowing what to do is sometimes tough to figure out.
Science is all about discovering how things work and trying to solve problems. Simple, hands-on experiments that begin with, “What do you think will happen?” or end with, “Can you make it happen differently?” get children’s minds in the right place. Even letting children “play” with the materials before beginning gets them thinking about how the materials work together. Encouraging children to help whenever they can by reading steps, measuring out materials, and cleaning up maximizes their learning experience and investment.
The following easy-to-set-up experiment involves mixing baking soda in water with some vinegar to create carbon dioxide gas. Raisins in this mixture will sit at the bottom at first, and then as the bubbles collect on the sides of the fruit, they will begin to float. When they reach the top, the bubbles on the raisins pop and the raisins sink back down. The cycle will repeat with the raisins going up and down until all of the bubbles are done.
Understanding buoyancy will help your children get the most from the experiment, so here’s a quick explanation. Buoyancy is a measure of how something floats or sinks in a liquid. Rolled up tin foil sinks in water, but if you make it into the shape of a boat, it floats. You change the density of the tin foil shape as you make it boat shaped. In this experiment, the raisins initially are too dense for the water, but the bubbles help to increase its buoyancy.
- A tall clear water glass
- baking soda
- paper towels
- Note: if you don't have vinegar and baking soda, 7UP or Sprite will do
- Fill a tall, clear water glass ¾ full of water (if no baking soda or vinegar, use the 7UP or Sprite)
- Mix 1 teaspoon of baking soda into the water until it is nearly clear (dilute the baking soda as needed)
- Put 2-3 raisins into the glass
- Observe how the raisins sit at the bottom and explain how the raisins are denser than the water
- Ask what will happen when you put vinegar into the baking soda water (this will test to see if they have any prior knowledge of mixing the two)
- Have the child pour approximately ¼ cup of vinegar into the glass (put paper towels under the cup in case it bubbles over)
- Watch the bubbles gather on the sides of the raisins and then slowly rise and then fall in the glass
This is a simple yet informative and exciting experiment for your kids to do. They’ll love the raisins bobbling up and down. And even if the vinegar and baking soda spills, it can be used as a safe cleaning agent, so just wipe it up.
The experimenting doesn’t have to be over yet, however. In fact, this is when the science really starts to happen. Your kids might ask if this will work with other types of fruit (Blueberries? Strawberries? Raisins?) They might choose a different cup size, differing amounts of baking soda and vinegar, or more or less water. Whatever they do, it’s in the name of science, and by encouraging their experimenting you will be encouraging their scientific minds.
Steve Davala is a middle school science teacher who likes to write. He’s got two kids of his own and subjects them to these science activities as guinea pigs. Follow him on Twitter or on www.stevedavala.com or email him at firstname.lastname@example.org.