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Hey there, it’s Calie again, bringing you another dose of fun and learning right from the comfort of your home.
Today, we’re delving into the soap and pepper science experiment that not only sparked curiosity in countless families but also went viral back in 2020 when we were all finding new ways to engage and learn indoors. Remember those days?
Well, one of the silver linings was discovering simple, yet fascinating, science experiments like the one I’m about to share: Exploring Surface Tension with nothing more than black pepper, soap, and water!
This experiment is a brilliant way to introduce the concept of surface tension to kids (and adults!) of all ages.
And the best part? It uses items you likely already have in your kitchen. Let’s dive in!
Supplies You Need for Pepper & Soap Science Experiment
- Ground black pepper
- A plate or bowl
- Water
- Liquid soap
Step-by-Step: How to Do the Pepper and Soap Experiment
- Start with the Setup: Fill your plate or bowl with a thin layer of water, less than an inch deep is fine. This will be your experimental surface.
- Pepper It Up: Sprinkle a generous amount of black pepper onto the water’s surface. The goal is to cover as much of it as possible. This step is visually fun and sets the stage for the main event.
- The Touch of Wonder: Dip your finger into the liquid soap, just a little dab will do. Now, gently touch the peppered water surface with your soapy finger.
- Watch in Amazement: Observe the immediate reaction as the pepper swiftly moves away from your finger, spreading towards the edges of the plate or bowl.
Why Does the Pepper Move? (The Science of Surface Tension Explained)
This simple yet mesmerizing experiment demonstrates the breaking of water’s surface tension by soap.
Surface tension is the elastic tendency of fluid surfaces to acquire the least surface area possible. It’s why water droplets form and why some insects can skitter across water surfaces. In our experiment, water’s high surface tension—thanks to its molecules’ strong attraction to each other—is disrupted by soap.
The soap molecules wedge themselves between the water molecules, reducing the water’s surface tension. As a result, the water molecules, trying to maintain their bond, retreat along with the pepper flakes, creating that wow-worthy movement.
Video: Watch the Pepper and Soap Experiment in Action
For a closer look and more fun, check out this engaging video: Exploring Surface Tension Video.
It’s a great companion to this activity and adds an extra layer of understanding and excitement.
Similar Experiments
Let me know if you do this experiment and how it went!
For more easy science experiments you can do at home with your kids, check out our main blog post called 100 Easy Science Experiments For Kids To Do At Home.
Warm wishes,
Calie
Calie Herbst, Editor-in-Chief of Milwaukee With Kids, has spent over a decade combining her experiences as a parent of three to create a hub for Milwaukee’s family adventures.
Her decade-long teaching career in Milwaukee Public Schools and academic background, including a Master’s in Teaching from Marquette University and dual B.A.s in Sociology and Spanish from the University of Wisconsin – Madison, fuel her passion for inclusive and engaging family content.
Calie is also a recognized voice in local media, contributing to WISN Channel 12 News, WTMJ Wisconsin Morning News, Fox 6’s Real Milwaukee, and B93.3.
Discover more about Calie’s journey and editorial approach on her About Page and Editorial Policy Page.
