How does a heart rate monitor on your wrist work?

What Crafty Clover says in this video

Intro

Hi there, curious minds! I'm Crafty Clover! Let's discover something amazing. How does a heart rate monitor on your wrist work?

The Big Idea

Some watches can count your heartbeat! How do they do it? With light!

Green Lights

Step one: Green Lights. Many watches shine tiny green lights onto your skin. Blood absorbs green light, so when your heart pumps a wave of blood, a sensor sees slightly less light bounce back.

Counting

Step two: Counting. The watch counts these changes to find your pulse. Chest straps use a different method that picks up the electrical signals of the heart.

Hard Work

Step three: Hard Work. Heart rate data helps athletes see how hard they are working. A resting heart rate is lower for people who are very fit.

A Closer Look

Let's take a closer look! Shines in. Absorbs it. Finds pulse. Electric signals.

Quick Facts

Quick facts! A resting heart rate is lower for people who are very fit. Green light on skin. Blood absorbs green. Shows how hard you work.

Think Like a Scientist

Now, think like a scientist! Find your pulse on your wrist. Count the beats for 15 seconds. Multiply that number by four. That is your heart rate per minute. Try again after jumping!

Outro

Many watches shine green lights on your skin, and because blood absorbs green light, a sensor sees changes each heartbeat and counts your pulse. Chest straps read electrical signals instead, and the data shows athletes how hard they work. Science is amazing! Remember, every big discovery starts with a small question. Keep looking, keep learning, and keep asking why! Crafty Clover can be found on Amazon Books, Google Bookstore, and Apple Books. Available for purchase or download! Bye for now!