Blue Shift/Red Shift

Okay, we learned that Oog, the caveman, sat on the beach and watched ocean waves. He noticed a stick bobbing in the water. Using his Mickey Mouse watch, Oog timed the number of times he saw the stick at the top of a wave during a one-minute time period. It was 60. The next day, it was 30, the next day it was 120. Hmmm. He discovered frequency, wavelength, and cycle.
Radio
The munchkins learned this same frequency and wave pattern works for radio -- most favor 97.7 radio station. They were shocked to learn the 97.7 means 97,700,000 Mhz or 97.7 million cycles per second.
Light
This same frequency equates to color. White light refracted into the seven-colors of the rainbow show blue is a short wavelength and red is a long wavelength. The wavelength determines if the light is coming toward you or away. With that, we learned objects in space, for the most part are moving away from us. We learned how doppler and sonar work, etc.
Math
Sine wave
Oscilloscope
Monitoring a hospital patients heartbeat, electrical impulses from electrical components.
All that from watching a stick in the water.
Have a great weekend, everybody.