WHAT TO GET:
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- A tealight candle
- An empty oatmeal or large yogurt container with a tight-fitting lid
- A penny
- A pen
- Scissors
- ADULT SUPERVISION
WHAT TO DO:
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- Place the penny in the center of the container’s lid, and trace around the edges.
- Carefully cut out the circle you marked so that you have a nice hole in the middle of the lid, and then put the lid back on the container.
- Place the candle near the edge of a table or countertop and have an adult light it.
- Hold the container to the side of the candle, so that the hole is lined-up with the candle flame and about 2 inches (5 cm) away.
- Give the bottom of the container a sharp tap and see what the sound waves do. It will take some experimenting to see how hard to tap. Try it from different positions and see what works best.
THE SCIENCE BEHIND THE EXPERIMENTS:
Vibrating objects create sound waves by bumping into air molecules, which bump into the air molecules next to them, which bump into the next ones, and so on. Just as vibrating objects create sounds, sound can also set up vibrations in the air. When those vibrations reach our eardrums, they cause vibrations that our brain picks up and interprets as sound. The sound waves that you create when you hum vibrate the plastic wrap. Even though you can’t see the vibration, the sprinkles can feel it and so they bounce up and down. Similarly, the sound of the tap on the bottom of the container causes the air molecules to move until they shoot out of the hole in the lid and snuff the candle.
SCIENTISTS ASK QUESTIONS:
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- Would this work with a smaller or a larger container?
- Does the size of the hole matter?
- How softly can you tap and still make the flame go out?
