Measuring Surface Tension with a Penny: Weekly Science Spotlight
What makes drops of water on a penny appear to pool together on the top of the penny as a large drop rather than run over the sides? Attraction of the water molecules holds the surface of the water together until the amount of water is too great and spills over the edge. This attraction results in surface tension—something we can see visually in the way the droplet may seem to hold together as a jiggly whole rather than flowing freely over the edges of a surface. You can see surface tension in the way rain drops collect when they hit a surface as well.
Surface tension may help keep the beverage you pour into a cup from overflowing, but sometimes you want to get rid of surface tension—like when you do the dishes If you need to disrupt surface tension, you need a solution that helps break the attraction between molecules. This kind of solution is called a surfactant. In this week's family science activity, explore the way soap decreases the surface tension of water by testing with water droplets on a penny.
You Might Also Enjoy These Related Posts:
- 10 Reasons to Do the Fluor Challenge in Addition to $10,000 in Prizes!
- Women's History Month: 50+ Women in Science and Engineering to Learn More About
- Learn More About these 28 Scientists for Black History Month
- STEM is for Everyone: Jane Goodall, Zoologist
- Coding Activities for Beginners and Beyond
- STEM is for Everyone: Annie Jump Cannon, Classifier of Stars
- 2020 Nobel Science Experiments for K-12 Students
- Halloween STEM Activities
Explore Our Science Videos
How to Make a Bristlebot
Two-Stage Balloon Rocket Introduction
Make a Lemon Volcano - Fun Science Experiment