Singing Spoon Materials
- metal spoon
- dry ice
Make the Spoon "Sing"
- Dip a spoon in hot water.
- Remove the spoon from the water and press the warm spoon against the cold dry ice. The spoon will cause the dry ice to sublimate into carbon dioxide vapor. You'll hear the spoon emit a sharp vibrating sound sort of like it is singing or screaming.
How the Singing Spoon WorksWhen you press the warm spoon against the dry ice, the sublimation speeds up. The carbon dioxide gas that is released presses against the spoon at the same time you are applying pressure to push the spoon into the dry ice. The oscillations in pressure occur very rapidly, producing sound waves.
Although you'll usually see this demonstration done using a spoon, it works with any metal object. Metal works best because of its high thermal conductivity, but feel free to experiment with other materials.