Why Can You See a Line of Light Under a Closed Door?

What Crafty Clover says in this video

Intro

Hi there, curious minds! I'm Crafty Clover! Let's discover something amazing. Why can you see a line of light under a closed door?

The Big Idea

You can see a line of light under a closed door because light squeezes through the gap! Light travels in straight lines, and it also bounces. The gap is narrow, so you see a thin line.

Straight Lines

Step one: straight lines. Light travels in straight lines. It goes through any gap that lets it pass.

Bouncing Light

Step two: bouncing. Light also bounces off the floor and walls of the bright room. Some of that bounced light heads toward the door.

Thin Gap

Step three: the gap. The light slides through the gap under the door and spills onto the floor of the dark side. A thin line of light is all you see because the gap is so narrow.

A Closer Look

Let's take a closer look! The bright room is full of light. Light bounces off the floor and walls. It squeezes through the thin gap. And draws a line on the dark floor.

Quick Facts

Quick facts! Shadows moving along the line tell you someone is walking by. The brighter the room, the brighter the line. A thicker door gap makes a wider line. Doors that fit tightly block more light.

Think Like a Scientist

Now, think like a scientist! In a dim room, close the door with a lamp on in the hall. Watch the line of light under the door. What happens to it when someone stands or walks near the door? Ask a grown-up to help with the lamp.

Outro

A line of light shows how light travels in straight lines and bounces. Science is amazing! Crafty Clover can be found on Amazon Books, Google Bookstore, and Apple Books. Available for purchase or download! Bye for now!