Selby's kitchen radio plays a song that arrived through the wall as a radio wave. Her ears hear sound. Is a radio wave just a kind of sound?
No, and the difference is what oscillates. This lesson puts the two waves side by side.
A radio wave is not a kind of sound, and the difference is what does the oscillating.
In a sound wave, particles of the medium oscillate: air particles swing back and forth as the wave passes.
The sound carries energy through the air while each air particle only swings about its rest position.
In a light wave, nothing material vibrates at all.
What oscillates is the wave's electric field and magnetic field.
When the song plays, the radio wave's fields oscillated on the way to the radio; the sound starts at the speaker, where the cone sets the kitchen's air oscillating.
A guitar note crosses a garage. What oscillates as the note travels?
A guitar note is a sound wave, and sound is mechanical.
In a mechanical wave, particles of the medium oscillate.
The garage's air particles oscillate, swinging about their rest positions as the note passes.
A laser beam crosses a workshop. What oscillates as the beam travels?
A laser beam is light, an electromagnetic wave.
In an electromagnetic wave, nothing material vibrates.
The beam's electric field and magnetic field oscillate; no particles of anything swing.
A lifeguard's whistle sends a sound wave across a pool deck. What oscillates as the wave travels?
Tove says: 'In a beam of light crossing a room, nothing material vibrates.' Is Tove correct?
Quenby says: 'A radio wave is a sound wave that travels through the air to the radio.' Is Quenby correct?
Which line correctly names what oscillates in a sound wave and in a light wave?
A sound wave travels through lake water toward a diver. What oscillates as the wave travels?
Starlight crosses a region of space that holds no material at all. What oscillates as the wave passes through that region?