Make Germs Scatter Science Demonstration

Kids will be amazed at this simple science demonstration that shows how using soap when washing hands literally makes “germs” scatter.

Yes, dish liquid is great for washing dishes, but there are so many other fun uses for soap. In the classroom I loved using this quick science activity to demonstrate the importance of using soap while washing hands.

With this simple science demonstration you can give kids a vivid visual that will help them remember to use soap each time they wash their hands {hopefully!}.

And bonus! They’re also learning a little about surface tension along the way.

Watch the Demonstration Video

You can watch the full science demonstration in this short video.

When we did this demonstration I started by gathering a bowl of water, black paper, and dish soap. Then I asked the girls to talk with me about what they know about soap and why we use it.

After our chat I told them we were going to learn about how soap makes germs scatter, and I asked them to sprinkle some pepper into our bowl. (Don’t add too much or the demonstration will not work as well.) They observed how the pepper floats on the surface of our water, and I told them that was like germs on the surface of our skin.

Then we covered one finger with dish soap. Our container was full so we just dipped a finger in, but you could also squirt the soap on the finger or dip a finger into a smaller container with soap poured in it.

Now for the big moment! And it’s a fast one, so make sure everyone is watching. Stick that finger into the water in the center of the bowl if possible. And POOF! Those “germs” scatter to the edge of the bowl. It’s quick, but powerful and kids remember that moment. Afterward we talked about how the “germs” are afraid of the soap and what we can learn from this demonstration.

This was always a powerful message that stuck with my kindergarteners when I was teaching in the classroom, and so far it’s had a lasting impression on my own girls as well.

A note about why this happens:

Inquisitive little scientists might want to know exactly why this happens since the pepper isn’t really “germs.” Basically the demonstration has more to do with the soap and water. The pepper just allows us to actually see what is happening. When soap is added to the water it lowers the surface tension of the water causing the water molecules on the surface to “scatter” or pull away from the point where you added the soap.

Don’t forget the hand washing song!

Help kids remember to wash long enough with a fun hand washing song for kids.