A loudspeaker does not throw air across the room. It pushes the air next to it back and forth, and that nudge passes from particle to particle as a pattern of squashed and stretched air racing outward as sound.
Sound is a longitudinal wave: the particles of the medium vibrate back and forth along the direction the wave travels, making compressions where they bunch together and rarefactions where they spread apart. Sound needs a medium, so it cannot travel through a vacuum.
A sound wave is a longitudinal wave in which the particles of the medium vibrate along the direction of travel, producing compressions (particles squashed together) and rarefactions (particles spread apart).
Sound needs a medium and cannot travel through a vacuum. The human ear hears roughly 20 Hz to 20 000 Hz.
See the loudspeaker push the air into compressions and rarefactions, and notice that each particle only vibrates on the spot.
Four quick checks. Each correct answer earns XP and lights this skill on your star map.
A sound wave is best described as...
In a longitudinal wave the particles of the medium vibrate...
A compression in a sound wave is a region where the particles are...
Sound cannot travel through...
In a longitudinal wave the vibration lies along the direction of travel, the opposite of a transverse wave.
Sound is longitudinal, not transverse. The particles move back and forth along the wave direction, they do not move across it, and they do not travel along with the wave. Because there are no particles to vibrate, sound cannot cross the vacuum of space.
Unlocks once the four checks above are done. Worth more XP, written in the style of Paper 2.
An astronaut outside a spacecraft cannot hear a hammer striking the hull nearby. The best reason is that...
The approximate range of frequencies a healthy human ear can detect is...
In a sound wave, the pressure is greatest at a...
Sound is mapped as a longitudinal wave. Keep the chain going.