Vibrations & Waves

Understanding mechanical vibrations, waves, and resonance

Topics

How do sound waves travel?

Sound waves travel by creating compressions and rarefactions in a medium like air, water, or solid materials. These pressure variations propagate outward from the source, transferring energy as they move.

How do standing waves form?

Standing waves form when two waves of the same frequency and amplitude travel in opposite directions and interfere with each other. The interference creates fixed points called nodes (no motion) and antinodes (maximum motion), creating a wave pattern that appears to stand still rather than travel.

How does an echo work?

An echo works through sound wave reflection. When sound waves hit a hard surface, they bounce back toward the source. If the reflected sound reaches your ears more than about 0.1 seconds after the original sound, your brain perceives it as a separate echo rather than part of the original sound.

How does resonance work?

Resonance occurs when an object is forced to vibrate at its natural frequency, causing it to oscillate with maximum amplitude. This happens when the frequency of an applied force matches the object's natural frequency.

What is a wave?

A wave is a disturbance that travels through space or matter, transferring energy without transferring matter itself. Waves can be mechanical (like sound or water waves) or electromagnetic (like light), and they all share common properties like wavelength, frequency, and amplitude.

What is amplitude?

Amplitude is the maximum displacement of a wave from its equilibrium position. For sound waves, amplitude determines volume (loudness), and for light waves, it determines brightness.

What is frequency?

Frequency is the number of complete wave cycles that pass a given point per second. It's measured in hertz (Hz) and determines the pitch of sound waves and the color of light waves.

What is the Doppler effect?

The Doppler effect is the change in frequency and wavelength of a wave observed when the source of the wave or the observer is moving relative to each other. When approaching, waves are compressed (higher frequency), and when receding, waves are stretched (lower frequency).

What is wavelength?

Wavelength is the distance between two consecutive points in a wave that are in the same phase, such as from one crest to the next crest or from one trough to the next trough. It's typically measured in meters and determines many wave properties including frequency and energy.

Why do some sounds travel faster than others?

Sound speed depends on the properties of the medium it travels through, not the sound itself. Sound travels faster in denser, stiffer materials—faster in solids than liquids, faster in liquids than gases. Temperature also affects speed in gases, with sound traveling faster in warmer air.