What is a Wave?

A wave is a way of moving energy from one place to another without moving matter. Think of it like a ripple in a pond: the water moves up and down, but the energy travels across the surface.

Types of Waves

1. Mechanical Waves: These need a material (like air, water, or ground) to travel through. Example: Sound.
2. Electromagnetic Waves: These can travel through empty space (vacuum). Example: Light.

The Three Main Properties

Every wave is defined by these three simple characteristics:

1. Wavelength

The distance between two consecutive peaks. It represents the "width" of a single wave cycle.

• Longer waves carry less energy.
• Shorter waves carry more energy.

2. Frequency

This is the "speed" of the vibration—how many waves pass a point each second.

• High frequency means waves are packed tightly together (Short wavelength).
• Low frequency means waves are spread far apart (Long wavelength).

3. Amplitude

The height or "strength" of the wave. It tells us how much energy is being carried.

• Large amplitude = Stronger energy (Loud sound or Bright light).
• Small amplitude = Weaker energy (Soft sound or Dim light).

Sound: Vibrations we Hear

Sound is a mechanical wave created by vibrations. It travels faster through solids than through air.

• Pitch (High vs Low): This depends on Frequency. High frequency sounds are "squeaky" (like a bird), while low frequency sounds are "deep" (like a drum).
• Loudness: This depends on Amplitude. The higher the wave, the louder the sound.

Light: Energy we See

Light is an electromagnetic wave. It is the fastest thing in the universe.

• Color: Different colors are actually different Frequencies. Red has the lowest frequency (longest wavelength), while Violet has the highest (shortest wavelength).
• Brightness: This depends on Amplitude. More amplitude means a brighter light source.

The Invisible Spectrum

Light is just a small part of a huge family called the Electromagnetic Spectrum.

• Low frequency: Radio waves, Microwaves, Infrared (heat).
• Visible: The colors we see.
• High frequency: Ultraviolet (UV), X-rays, Gamma rays.

How Waves Behave

When waves hit obstacles or change materials, they do interesting things:

• Reflection: Bouncing off a surface (like a mirror or an echo).
• Refraction: Bending when entering a new material (like a straw looking broken in water).
• Diffraction: Spreading out around corners or through gaps.

Summary