📘 Wave Properties
A wave is a disturbance that travels through a medium, transporting energy from one location to another without transporting matter. To understand waves, we have to master the “anatomy” of the wave itself.
Audio Explanation
Prefer to listen? Here's a quick tour of the anatomy of a wave and the energy it carries.
Anatomy of a Wave
Whether it’s a ripple in a pond or a pluck of a guitar string, most waves share these core features:
- Crest: The highest point of the wave.
- Trough: The lowest point of the wave.
- Amplitude ($A$): The maximum displacement from the equilibrium (center) position. This is directly related to the energy of the wave.
- Wavelength ($\lambda$): The distance between two consecutive identical points (like crest to crest).
Visual Representation
The Universal Wave Equation
All waves follow a fundamental mathematical relationship. The speed of a wave depends on how often it repeats (frequency) and the size of each cycle (wavelength).
\[v = f\lambda\]- $v$: Wave speed (m/s).
- $f$: Frequency (Hz).
- $\lambda$: Wavelength (m).
Important Rule: The speed of a wave ($v$) is determined solely by the medium (like air, water, or a string). If you increase the frequency, the wavelength must decrease to keep the speed the same!
Interactive Wave Lab
Use the sliders to change the frequency and amplitude of the wave. Observe how the “balls” (matter) only move up and down while the “wave” (energy) moves to the right.
Wave Motion Visualizer
Wave Speed (v):
CONSTANT
Wavelength (λ):
--- m
Transverse vs. Longitudinal
Waves are categorized by the direction the medium moves compared to the direction the energy moves.
| Wave Type | Medium Direction | Example |
|---|---|---|
| Transverse | Perpendicular (Up/Down) | Light, S-Waves (Earthquakes), Guitar Strings |
| Longitudinal | Parallel (Back/Forward) | Sound, P-Waves, Compressed Springs |
[Image of a slinky showing transverse vs longitudinal waves]
Interactive Match: Wave Variables
Match the physical change to the wave characteristic it represents.
Why Should I Care?
Everything you see and hear is a result of wave properties:
- Color: Your eyes interpret different wavelengths of light as different colors (Red is long, Violet is short).
- Pitch: Your ears interpret different frequencies of sound as different musical notes.
- Volume: A louder sound simply has a higher amplitude (more energy).
💡 Quick Concept Check:
If you are standing on a pier and notice the wave crests are 4 meters apart, and a new crest hits the pier every 2 seconds, how fast are the waves moving?