When Your Fridge Becomes a Lab: The Fascinating World of Standing Waves Drawn with Springs and Magnets
I’m Ken Kuwako, your science trainer. Every day is an experiment!
Whether it is the beautiful melody of a guitarist at a concert or the soothing sound of someone singing in the shower, invisible waves are hidden behind every sound we hear. Wouldn’t it be exciting if you could create a mysterious world where those waves appear to stand still, right in the palm of your hand? Today, I will share a clever trick to observe standing waves—a fan favorite in science class—easily at home, all by yourself.
The Art of Waves Created with a Slinky
Have you ever seen the long metal springs used in science labs for wave experiments? For science teachers, these are essential tools because they allow us to recreate standing waves so clearly it looks like you are watching strings vibrate in slow motion. Usually, this experiment requires two people: one person to hold the end firmly while the teacher shakes the other end. While I often ask students to help with this demonstration in class, I’ve always been bothered by the fact that if a student thinks, “I want to try this at home!”, it’s difficult to do without a partner.
A Science Recipe for Solo Exploration
Most people don’t have lab-grade springs at home, and finding a way to anchor one end by yourself can be a real challenge. That is why I want to share a brilliant workaround for solo experimentation, inspired by my colleague, Mr. O. Thank you, Mr. O, for this fantastic idea!
The Science Recipe
What You’ll Need:
A spring or Slinky (available at hobby shops like Tokyu Hands), and a magnetic clip.
If you don’t have a hobby shop nearby, a heavy-duty bungee cord from a hardware store works as a great substitute!
Steps:
Attach the magnetic clip to one end of the spring.
Stick the magnetic clip onto a refrigerator, a whiteboard, or any metal surface.
This use of a magnet for anchoring is the most important part of the trick! It holds the delicate spring firmly without damaging it and can be set up almost anywhere. It’s a simple yet revolutionary idea!
Hold the other end yourself and shake it rhythmically.
Shapes that Shift with Speed! The Amazing Standing Wave
As you begin to shake the spring, beautiful standing waves will emerge. A standing wave is a fascinating phenomenon where an outgoing wave and its reflection overlap, making the wave appear to vibrate in place rather than traveling. If you shake it slowly, you get the fundamental frequency—a single large arc. Shake it a bit faster, and you’ll see the second harmonic with a still point (a node) in the middle. Faster still, and you get the third harmonic!
Fundamental Frequency
Second Harmonic
By simply changing your hand’s frequency (the speed of your shaking), the wave patterns shift one after another. It feels almost like playing a musical instrument!
With just a little bit of ingenuity, physics becomes so much more relatable. You don’t need massive equipment to touch the laws of nature—using everyday items is the true essence of science. On a side note, a child once told me that these springs make an incredibly interesting movement when dropped down stairs. I actually tried it out myself, and you can see it here:
Do you know any other fun experiments involving waves? If you have any great ideas, I’d love to hear them!
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