How Light Travels

Light is a form of energy that allows us to see the world around us. Understanding how light moves helps us explain shadows, reflections, and why we cannot see around corners.

Light travels in straight lines called light rays. A light ray is the path that light follows as it moves from one place to another. When you turn on a flashlight, the light does not curve or bend around objects on its own. Instead, it travels forward in a straight path until something blocks it or it hits a surface.

A light source is any object that produces light, like the sun, a lamp, or a flashlight. Light spreads out from its source in all directions, but each individual ray travels in a straight line. Think of light rays like arrows shot from a bow—they fly straight ahead until they hit something.

Because light travels in straight lines, it creates shadows. A shadow is a dark area that forms when an object blocks light. When you stand between a lamp and a wall, your body blocks some of the light rays traveling in straight lines. The rays cannot bend around you to reach the wall, so a shadow appears in the shape of your body.

This is also why you cannot see around corners. Light from objects around the corner cannot bend to reach your eyes. The light rays travel straight and are blocked by the wall. If you want to see what is around the corner, you must move so that light rays from that area can travel in a straight line to your eyes.