How are sound and light alike and different?
Sound and light are similar in that both are forms of energy that travel in waves. They both have properties of wavelength, freqency and amplitude. Here are some differences:
- Sound can only travel through a medium (substance) while light can travel through empty space.
- Sound is a form of mechanical energy caused by vibrations of matter. Light is electromagnetic energy caused by interacting electric and magnetic fields.
- A light wave is a transverse wave, meaning that its displacement is perpendicular to its direction of travel. (Picture a sine wave or an ocean wave.) A sound wave is a longitudinal wave, meaning that its displacement is the direction it travels. It's also called a compression wave. Picture a Slinky toy (spring) being stretched and compressed longitudinally.
- Light travels much faster than sound. It travels at a speed of about 300 million meters per second, while sound travels at about 340 meters per second depending on altitude and air temperature.
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