STUDENT INFORMATION

Experiment 9.1: Sound Wave Visualization

Can we see the effect of sound waves traveling through air?

In this experiment, you'll explore how sound waves travel through air by observing their effects on a candle flame and rice grains.

Materials Needed:

Part 1: Candle Flame + Sound Waves

Sound waves are moving air pressure changes. When the air pressure near a candle changes rapidly, the flame can flicker.

What to do (real experiment)

  1. Place a candle on a stable, non-flammable surface and light it.
  2. Stand the large bottle between you and the candle (this helps block your breath from affecting the flame).
  3. From the other side of the bottle, clap, talk loudly, or tap the bottle gently and watch the flame.
  4. Try different distances. Do you see the flicker change?

Safety: Adult supervision required. Keep hair/sleeves away from flame. Never leave a candle unattended.

Part 2: Rice Grains + Vibrations

Current experiment step

Real Experiment Photos

Here's what the actual experiment setup and process looks like:

Empty bowl setup

Step 1: Empty bowl setup

Bowl covered with plastic wrap

Step 2: Bowl covered with plastic wrap

Rice grains on plastic wrap

Step 3: Rice grains placed on plastic wrap

Pot positioned above bowl

Step 4: Pot positioned above bowl

Watch the Experiment in Action

Video demonstration of rice grains bouncing when the pot is hit

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Conclusions:

Based on your observations, answer the following questions:

  1. What happened to the candle flame when you flicked the plastic wrap? Why?
  2. What happened to the rice grains when you banged the pot? Why?
  3. How do these observations help us understand sound waves?