Comparing Light Waves and Sound Waves

Light Waves

Light waves are a type of electromagnetic waves that are responsible for the sensation of sight. These waves can travel through a vacuum, such as space, allowing us to observe objects in space, from Earth.

An illustrative diagram titled "LIGHT" explains that electromagnetic waves are transverse waves. The sun is depicted on the left, emitting a wavy light ray that travels across different mediums: vacuum in space, atmosphere, and water. In space, a rocket and a planet are shown. On the right side, an eye is observing the visible light spectrum, with the wave being most pronounced in the water. The background transitions from deep blue to light blue, symbolising the different mediums the light passes through.

Sound Waves

Sound waves are mechanical waves that require a medium, (e.g. air, water or a solid substance) to carry their energy forward.

They are created by vibrations, like a plucked guitar string or a speaking voice, which cause compressions and rarefactions in the surrounding medium. These waves allow us to hear sounds, from the softest whisper to the loudest explosion.

An informative diagram titled "SOUND" demonstrates that sound waves are longitudinal waves. On the left, an astronaut floats in a vacuum of space with a speech bubble exclaiming "SHHH! No Sound in Vacuum!" to highlight the absence of sound in space. In the centre, a siren is shown with a label that reads "Siren Vibrates", producing sound waves that radiate outwards. On the right, a child stands on a pier, experiencing the sound waves in the air as the label indicates "Air Vibrates". Beneath the pier, a diver in water also senses the vibrations, with a label pointing out "Water Vibrates". The background transitions from deep blue, representing the vacuum, to a light blue, symbolising air and water where sound can travel.

The table below shows us the differences between light and sound waves.

Light wavesSound waves
Type of waveTransverseLongitudinal
Can they travel through a vacuum?YesNo
How are they detected?Eyes and camerasEars and microphones
Can they be refracted?YesYes
Can they be reflected?YesYes

he speed of sound is roughly 343 m/s, whereas the approximate speed of light through a vacuum is 300,000,000 m/s.

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