Why Does a Lamp Look Dimmer the Farther Away It Is?

What Crafty Clover says in this video

Intro

Hi there, curious minds! I'm Crafty Clover! Let's discover something amazing. Why does a lamp look dimmer the farther away it is?

The Big Idea

A lamp looks dimmer the farther away it is because its light spreads out! Farther away, the light is thinner. Your eyes catch less of it.

Light Spreads

Step one: light spreads. Light spreads out in every direction as it leaves a lamp. Farther from the lamp, the same light covers more space, so each spot gets less.

Double Distance

Step two: double the distance. If you double your distance, the light covers four times as much area. So it looks only one-quarter as bright.

Far and Small

Step three: faraway lights. That is why a faraway streetlight looks small and dim. The Sun is so far away that Earth gets only a tiny part of its light.

A Closer Look

Let's take a closer look! The lamp gives off its light. The light spreads as the distance grows. It gets thinner and thinner. So a faraway lamp looks like a dim dot.

Quick Facts

Quick facts! Twice as far means one-quarter as bright. Three times as far means just one-ninth as bright. The Sun is about 93 million miles away. Even so, sunlight is far too bright to look at.

Think Like a Scientist

Now, think like a scientist! At dusk, with a grown-up, have a friend walk away from you holding a flashlight. They should keep it pointed at the ground, not at your eyes. How does the light change as they go? At how many steps can you barely see it? Count them out loud.

Outro

A lamp looks dimmer far away because its light spreads out. Science is amazing! Crafty Clover can be found on Amazon Books, Google Bookstore, and Apple Books. Available for purchase or download! Bye for now!