Explainer: Understanding Waves and Wavelengths

Key Concepts

• Wave Definition: Waves are disturbances that transfer energy from one place to another without moving matter.
• Medium: The substance through which a wave travels. The medium moves back and forth but returns to its original position.

Types of Waves

• Seismic Waves: Shake the ground during earthquakes.
• Light Waves: Travel across the universe.
• Sound Waves: Every sound we hear is a wave.

Wave Characteristics

Movement

• Waves have crests (high points) and troughs (low points).
• Example: Shaking a rope creates a wave where the rope acts as a medium.
  • Hand movement creates a crest and trough.
  • Energy moves along the rope; the rope itself does not travel.
• Similar behavior in ocean waves and light waves (electromagnetic radiation).

Electromagnetic Waves

• Light is an electromagnetic wave.
• Travels through electromagnetic fields, which oscillate when disturbed.
• Unlike other waves, light doesn't need a physical medium to travel; it can move through empty space.

Properties of Waves

• Wavelength: The distance between two identical points on consecutive waves (e.g., crest to crest).

  • Ocean waves: ~120 meters
  • Microwaves: ~0.12 meters
  • Visible light: Tiny wavelengths

• Frequency: Number of waves passing a point per second, measured in hertz (Hz).

  • Example: Music note with frequency of 261.6 Hz moves air molecules that many times per second.
  • Higher frequency means more energy and shorter wavelength.

Applications

• Researchers utilize wave properties in fields like astronomy and geology.
• Tools that capture reflected sound, light, or radio waves are used to map objects.

Electromagnetic Spectrum

• Ranges from long wavelengths (e.g., radio waves) to short wavelengths (e.g., gamma rays).
• Human eyes can only see a small portion of this spectrum.

Power Words

• Definitions of key terms such as astronomer, crest, electromagnetic radiation, frequency, hertz, and wavelength.

This article provides a comprehensive overview of waves, their behavior, and their significance in various scientific fields.