Why Can a Laser Measure How Far Away a Wall Is?

What Crafty Clover says in this video

Intro

Hi there, curious minds! I'm Crafty Clover! Let's discover something amazing. Why can a laser measure how far away a wall is?

The Big Idea

A laser measuring tool finds a distance by timing a flash of light! The flash bounces off the wall and comes back. A clock inside measures how long the trip took.

Send a Flash

Step one: send a flash. The tool sends a very short flash of laser light at a wall. It starts a super-fast clock at the very same moment, like a stopwatch for light.

Bounce Back

Step two: bounce back. The light bounces off the wall and returns to the tool. The clock stops, and the trip time is saved. It is a tiny fraction of a second.

Do the Math

Step three: the math. Light always moves at the same speed, so the tool multiplies the time by that speed. Then it divides by two, because the light went to the wall and back.

A Closer Look

Let's take a closer look! A flash leaves the tool. It hits the wall. It bounces straight back. And the screen shows the distance.

Quick Facts

Quick facts! Builders measure rooms in seconds with these tools. Light crosses a room in a few billionths of a second. The tool's clock has to be extremely fast. Laser measures help map land and buildings too, and they are safe when used by a grown-up as directed.

Think Like a Scientist

Now, think like a scientist! Ask a grown-up to use a laser measure to find the width of a room. The laser points only at the wall, never at a person. Then measure the same distance with a tape. How close are the answers?

Outro

A laser measure times a flash of light to find a distance. Science is amazing! Crafty Clover can be found on Amazon Books, Google Bookstore, and Apple Books. Available for purchase or download! Bye for now!