Balancing a Potato. An Experiment with Gravity

🎂 7 + years ⏱️ 15 min 📍 Anywhere ⭐ medium

Can you balance a potato on your finger? At first glance, it seems impossible. As soon as you place it down, it rolls to the side and falls. The reason is gravity, which pulls everything down to the Earth, and the center of mass, which is quite unevenly distributed in a potato. But with a little trick, you can perform an amazing experiment: if you stick two forks into the potato, its center of mass changes. Suddenly, you can balance it steadily on your finger, almost like an artist in a circus. You’ll learn how physics works in a playful way. Simple things like a potato show you that exploration is possible everywhere.

What you'll need

A raw potato
2 forks

How it works

Imagine the potato is a circus artist. It wants to perform a daring act right on your index finger. You carefully place it down. But whoops, it tips over immediately. Why? Gravity pulls it down, and its center of mass is unevenly distributed.
The potato is frustrated because it keeps tipping over. Then it gets help from two forks. You stick them in on the right and left sides of the potato. Now it looks a bit like it has wings. But even more exciting: its weight is redistributed.
With its 'wings', the potato takes to the stage again. You balance it on your finger once more. And this time? It wobbles a bit… but stays up! The audience is amazed.
The forks pull the weight down. The center of mass is now positioned so that gravity doesn’t tip it over immediately. Like an artist, the potato finds the perfect balance.
Now experiment. Try balancing the potato on your thumb or on a pencil. See where it holds and where it doesn’t. This way, you learn playfully that gravity pulls down and the center of mass determines balance.