Physics

Study of matter, energy, and their interactions in the universe.

Basic Concepts

Waves and Light

What Are Waves?

Waves are ways that energy moves through space. There are two main types:

  • Mechanical waves: Need something to travel through (like sound in air).
  • Electromagnetic waves: Travel through empty space (like light).

Light: The Fastest Traveler

Light is an electromagnetic wave. It travels incredibly fast—about 300,000 kilometers per second! Light lets us see, warms the Earth, and helps plants grow.

How Waves Behave

Waves can reflect (bounce), refract (bend), and interfere (combine with other waves). These behaviors explain rainbows, echoes, and how glasses help us see better.

Fun with Sound

Sound waves are mechanical waves—when you pluck a guitar string, the vibration travels through the air to your ears.

Examples

  • You hear music because sound waves travel through the air.

  • Sunlight passing through water creates a rainbow.

In a Nutshell

Waves carry energy, and light is a special wave that lets us see the world.

Key Terms

Wave
A disturbance that transfers energy from place to place.
Electromagnetic Wave
A wave, like light, that can travel through empty space.
Reflection
When a wave bounces off a surface.