Detecting UV Light | AMNH https://www.amnh.org/learn-teach/curriculum-collections/discovering-the-universe/detecting-uv-light
You can’t see the Sun’s ultraviolet rays with your eyes—you just see their results on your freckled, tanned, or sunburned skin. Build a bracelet that immediately detects these invisible rays.
Rainier Retrieving a Stromatolite from the Sahara