Sound Wave Salt Plate Visualization
Sprinkle salt on a plate over a speaker and watch it dance into patterns when music plays — sound waves made visible and touchable.
What You'll Need
- 1Portable Bluetooth speaker
- 2Thin plate or plastic wrap
- 3Fine salt
- 4Phone or device for tone generator
- 5Optional: sugar, pepper, sand for comparison
What You'll Need
A portable Bluetooth speaker
A thin plate or plastic wrap stretched taut
Fine salt
A phone or device with a tone generator app
Optional: sugar, pepper, and sand for comparison
How to Play
Place a speaker face-up and set a thin plate on top.
Sprinkle a thin, even layer of salt across the plate.
Play a single sustained tone (use a free tone generator app).
Watch the salt dance and settle into geometric patterns.
Change the frequency — try 200Hz, 400Hz, 800Hz — and watch patterns morph.
Lower frequencies create larger, simpler patterns. Higher frequencies create smaller, more complex ones.
Swap salt for sugar or pepper and compare how different materials respond.
Tips
These patterns are called Chladni figures, discovered in the 1700s. Your child is recreating a real physics experiment.
The salt collects along the nodal lines — places where the surface isn't vibrating.
Use a phone's slow-motion camera to capture the salt bouncing. The footage is mesmerizing.
Try playing actual music instead of tones — the patterns become chaotic and beautiful.
This makes sound visible. Kids who are visual learners suddenly understand sound waves in a way words can't convey.
Frequently Asked Questions
How long does this activity take?
This activity takes about 20 min, with 5 min of preparation time beforehand.
What materials do I need?
You'll need: portable bluetooth speaker, thin plate or plastic wrap, fine salt, phone or device for tone generator, optional: sugar, pepper, sand for comparison.
What age is this activity for?
This activity is designed for 8-12 years. You can adapt it for younger or older children by adjusting the complexity.
Can this be done indoors?
This activity is designed for indoor play, making it perfect for rainy days or when you're staying inside.
How difficult is this activity?
This activity has a moderate difficulty level. It may require some preparation or guidance, but is manageable for most families.
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