What is 650 nm?

650 nm is a tiny little measurement that helps us see colors like red and orange.

Imagine you're playing with a flashlight in a dark room. The light from your flashlight travels as waves, just like the ripples on a pond when you throw a rock in. These waves have different sizes, or lengths, and 650 nm is one of those sizes, it's about the width of a really tiny grain of sand!

When light with a wave length of 650 nm reaches your eyes, you see red, like the color of a ripe apple or a fire truck. If the waves are slightly shorter, like 600 nm, you might see orange, just like a juicy orange in your lunchbox.

Scientists use these tiny measurements to understand how light works. It's like having a special ruler that helps us measure things we can't even see with our eyes, but we can definitely feel and enjoy!