Pepper and Soap Science Experiment: Easy Hand Washing Activity for Kids

Kids will be amazed by this simple pepper and soap science experiment that shows how using soap while washing hands makes “germs” scatter. This easy hand washing science demonstration is a memorable visual activity for preschool, kindergarten, and elementary kids.

Looking for a quick and meaningful hand washing science experiment for kids? This simple pepper and soap experiment is one of the easiest ways to show children why soap matters when washing hands.

Yes, dish liquid is great for washing dishes, but it is also a helpful tool for hands-on science. In the classroom, I loved using this quick germ science activity to demonstrate the importance of using soap instead of only rinsing with water.

With this simple science demonstration, you can give kids a vivid visual that helps them remember to use soap each time they wash their hands. The pepper acts like pretend germs, and when soap touches the water, the “germs” quickly scatter.

Bonus! Kids are also learning a little about surface tension along the way. Science projects at home and in the classroom are always more fun when kids can see the reaction happen right in front of them.

Pepper and Soap Science Experiment for Kids

Sometimes the simplest experiments make the biggest impact. This easy pepper germs experiment is not only fun to watch, but it also gives kids a concrete way to understand why washing hands with soap is important.

We like to talk about all types of science topics in our home and then follow those conversations with a simple experiment whenever possible. Hands-on activities like this make learning fun and create a stronger connection between real-life habits and science concepts.

What we enjoyed most about this soap and pepper experiment is that it can be done quickly in science class, at home, or as part of a health and hygiene lesson. It also makes a cool exhibit or demonstration for a science fair because the reaction is fast, visual, and easy for children to explain.

This activity works well for many ages. It can be used as a preschool science lesson, a kindergarten hand washing activity, or a simple elementary science experiment. Older kids can take the investigation further by learning about the experimentation process, making predictions, and exploring how soap changes the surface tension of water.

This is one of those amazing science experiments kids want to do over and over again. They love watching the pretend germs scatter, and the visual reminder helps reinforce an important healthy habit.

Watch the Hand Washing Science Demonstration Video

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

Supplies for the Pepper Germs Experiment

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.

You only need a few basic supplies for this easy science experiment for kids:

• A bowl or shallow dish of water
• Black pepper
• Dish soap or liquid hand soap
• Black paper or a dark surface, optional

How to Do the Pepper and Soap Experiment

After our chat, I told them we were going to learn about how soap makes germs scatter. I asked them to sprinkle some pepper into our bowl of water. Don’t add too much pepper, or the demonstration will not work as well.

Have kids observe how the pepper floats on the surface of the water. Explain that, for this science demonstration, the pepper is pretending to be germs on the surface of our skin.

Next, cover 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! This part happens fast, so make sure everyone is watching. Stick the soapy finger into the water in the center of the bowl if possible.

And POOF! Those “germs” scatter to the edge of the bowl. It is quick, but powerful, and kids remember that moment. Afterward, we talked about how the “germs” move away from 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 has had a lasting impression on my own girls as well.

The Science Behind This Hand Washing Demonstration

A note about why this happens:

Inquisitive little scientists might want to know exactly why the pepper moves away from the soap, since the pepper is not really germs. Basically, this demonstration has more to do with the soap and water. The pepper simply allows kids to see what is happening on the surface of the water.

Water has surface tension, which helps the pepper float on top. When soap is added to the water, it lowers the surface tension and causes the water molecules on the surface to pull away from the point where the soap was added. As the water moves away, the pepper moves with it, making the pretend “germs” scatter.

That visual connection is what makes this surface tension experiment for kids such a helpful hand washing activity. Children can see that soap changes what happens on the surface, which helps them remember that soap is an important part of getting hands clean.

More Hand Washing Tips and Resources

Don’t forget a helpful hand washing song!

Help kids remember to wash long enough with a fun hand washing song for kids. Over on Fun-A-Day you can grab the free printable pictured below and see a collection of YouTube videos about hand washing to choose from.

Teach curious kids the history of hand washing!

Max Brooks shares the history of hand washing over on History.com. There’s even a free printable activity that includes another fun science experiment about germs.

Get help teaching 13 key classroom procedures

We know there are more routines to teach in the classroom than hand washing.

This 605 page classroom procedures bundle is full of step-by-step instructions for everyday routines children engage in at school, along with helpful tips and guidance to help you teach clear and detailed steps for 13 key classroom routines to your students.

As a bonus, we’ve added social distancing and online learning routines to accommodate today’s unprecedented learning environment. 

Also available on Teachers Pay Teachers.