http://ecampus.matc.edu/mihalj/astronomy/test3/physics_of_light.htm
https://www.cancer.gov/about-cancer/causes-prevention/risk/radiation/cell-phones-fact-sheet
https://i.ytimg.com/vi/vin2CjR7viI/maxresdefault.jpg
https://tenor.com/search/next-time-gifs
rays picture
Waves/Rays
phone
How did we know this?
7