Attenuated total reflectance

Attenuated total reflectance is like using a special mirror to look at things really close up. When light shines on something, it bounces off and comes back to our eyes. But sometimes the things we want to look at are too small or thin to bounce enough light back to our eyes. That's where the special mirror comes in.

The mirror is made of a material that lets some light in and bounces some light back out. When we put the thing we want to look at really close to the mirror, the light bounces back and forth between the mirror and the thing, and eventually enough light comes back to our eyes so we can see it. It's like when we whisper in a tunnel and the sound bounces back and forth until someone at the other end can hear us.

Scientists use attenuated total reflectance to study things like tiny particles or super-thin layers of material. It helps them see things that are too small or thin to see with normal light.