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Pepper & Soap Science Experiment

The pepper and soap science experiment is a classic activity that kids can do at home with just a few simple materials. It is a fun and easy way to introduce children to the basics of science and chemistry. This pepper and soap activity can be used to teach about germs, buoyancy, sink/float and more! This experiment can help children develop their observation and critical thinking skills as they try to explain what they are seeing. In this blog post, we will take a closer look at the pepper and soap science experiment and explore how it works.


  • Easy


  • Plate/Bowl

  • Water

  • Pepper

  • Soap


  • Have the kids pour the water into a plate.

  • Then sprinkle pepper on the water.

  • Touch the water without and with soap on your hand.

  • What happens?


  • What do you think will happen once you touch the water without soap? what will happen with soap?

  • What did you see? Why?

  • What if we change the liquid to milk? or juice? oil?


When the soap touches the surface of the water, it reduces the surface tension of the water. Surface tension is the force that holds the surface of a liquid together, and the reduced surface tension allows the pepper to move away from the area where the soap was added. This is why the pepper appears to move away from the soapy toothpick or cotton swab. The pepper particles are pushed to the edges of the dish, leaving a clear spot in the center.

The pepper and soap science experiment is a simple way to introduce children to the concept of surface tension and how it can be affected by other substances. It is also a great way to teach children about the properties of soap and how it can interact with water.


  • Adult supervision required for any of these activities. Please supervise and make sure children participating are safe. Read instructions and the safety labels from each material.


  • This blog post may contain affiliate links for your convenience. I may receive a commission for purchase made through links in this post.


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