Welcome! Today we will explore how sound and light travel as energy.
Sound and light are both forms of energy that travel in waves. Sound needs a medium like air or water to move, but light can travel through empty space.
Sound waves vibrate particles back and forth in compressions. We can analyze how these vibrations form peaks and troughs to measure their frequency.
Light waves move much faster than sound waves. When we compare them, light travels at 300,000 kilometers per second, while sound only moves at 343 meters per second in air.
✏️ Worked example
Determine which travels faster through air: a lightning flash or its thunderclap.
Step 1: Identify the two phenomena (light from lightning, sound from thunder).
Step 2: Recall the speed of light in air (300,000,000 meters per second).
Step 3: Recall the speed of sound in air (343 meters per second).
Step 4: Compare the speeds: light travels nearly one million times faster than sound.
Step 5: Conclude that you see the lightning flash before you hear the thunder.
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