Soap vs Germs

Hosted by: UT Austin Physics Circus

Watch our show on "The Science of Germs​" and then do the experiment below at home.

Recommended Grades: 1st, 2nd, 3rd

The Challenge: Push germs away with soap by breaking the surface tension of water. Pour a little bit of water onto your plate or bowl. Then, sprinkle a little bit of ground black pepper over the surface of the water. Take your q-tip and dab a little bit of dish soap on the end. Gently lower the q-tip into the center of the plate or bowl and watch what happens to the black pepper as you touch the surface of the water! 

Recommended Materials: white plate or bowl, water, ground black pepper, q-tip, dish soap

STEM Connections: Science can help us understand ways to keep our minds and bodies healthy and improve our quality of life, as well as that of others. This demonstration shows us the power of soap in keeping our hands free of germs. One thing we can all do to keep ourselves healthy, as well as those around us, is to wash our hands often. We can see how powerful soap is at pushing away germs off of our hands, which are then rinsed down the drain with running water.

Water molecules like to hang out close to each other. This is what makes surface tension possible. But when the mighty soap intervenes, it breaks up their group and the water molecules run away from the soap, pushing away anything in their way, including germs.

Activity Video

Follow along with us as we break the surface tension of water to drive germs away with soap! 

 

About the UT Austin Physics Circus

We are a traveling physics show that brings exciting and educational science demonstrations to the classroom. Our mission is to make science a fun and interactive experience for all, regardless of economic background, race, or gender. This is why we offer the show at no cost to the school. Our program is proudly driven by the enthusiasm of physics graduate students at UT who are passionate about science outreach to the Austin community.

Please visit our website if you'd like to read more about the Physics Circus, view our promotional video, or inquire about shows.