01What is a wave?
A wave transfers energy without moving matter permanently from place to place.
In a transverse wave, particles vibrate at right angles (90°) to the direction the wave travels (e.g. light, water ripples).
In a longitudinal wave, particles vibrate along (parallel to) the same direction the wave travels, creating compressions and rarefactions (e.g. sound).
02Wave properties
Every wave can be described using these key properties:
- Amplitude — maximum displacement from the resting position (relates to energy/loudness/brightness)
- Wavelength (λ) — the distance between one point on a wave and the same point on the next wave
- Frequency (f) — number of complete waves passing a point each second, measured in hertz (Hz)
03Sound waves
Sound is a longitudinal wave made by vibrating objects. It needs a medium (solid, liquid or gas) to travel — sound cannot travel through a vacuum (empty space), because there are no particles to vibrate.
Sound travels fastest through solids, slower through liquids, and slowest through gases like air.
04Pitch and volume
Pitch (how high or low a sound seems) depends on frequency: higher frequency = higher pitch.
Volume (loudness) depends on amplitude: bigger amplitude = louder sound.
05How we hear
Sound waves travel through air and enter the ear canal, making the eardrum vibrate. These vibrations pass through tiny bones in the middle ear and are converted into nerve signals the brain interprets as sound.
| Term | 한국어 | Meaning |
|---|---|---|
| transverse wave | 횡파 | Particles vibrate at right angles to wave travel |
| longitudinal wave | 종파 | Particles vibrate parallel to wave travel |
| amplitude | 진폭 | Maximum displacement from rest position |
| wavelength | 파장 | Distance between two matching points on a wave |
| frequency | 진동수 | Number of waves per second (Hz) |
| pitch | 음높이 | How high or low a sound seems |
| vacuum | 진공 | Space with no particles; sound cannot travel here |