How Does an Altimeter Know How High a Plane Is?

What Crafty Clover says in this video

Intro

Hi there, curious minds! I'm Crafty Clover! Let's discover something amazing. How does an altimeter know how high a plane is?

The Big Idea

How does an airplane know how high it is? It feels the air! The tool is called an altimeter.

Pressure Drops

Step one: pressure drops. An altimeter measures air pressure. The higher you go, the less air is above you, so the pressure becomes lower.

Pressure to Height

Step two: pressure to height. The instrument turns that pressure into a height reading. Pilots must adjust it for the day's weather, because air pressure changes.

Radio Altimeter

Step three: radio altimeter. Planes also have radio altimeters that bounce signals off the ground. They measure the distance when landing.

A Closer Look

Let's take a closer look! Higher means less air above. The pressure drops. The dial shows height. A radio signal checks near the ground.

Quick Facts

Quick facts! Air pressure drops by about half at eighteen thousand feet. Weather changes the air pressure every day. Radio altimeters bounce signals off the ground. Pilots adjust the dial for the weather.

Think Like a Scientist

Now, think like a scientist! With a grown-up, check a weather app that shows air pressure. Look at it each day for a week. See how it changes. Write the numbers down. Tell a grown-up what you discover!

Outro

An altimeter measures air pressure, which gets lower the higher you go, and turns it into a height reading. Science is amazing! What will you discover next? There is always more to discover, and you are a great science explorer! Ask a grown-up to help you try the mission, and see what you can find out. Crafty Clover can be found on Amazon Books, Google Bookstore, and Apple Books. Available for purchase or download! Bye for now!