Question

Our teacher wore a t-shirt with red lettering that read "if what you're reading is blue you're running to fast" and asked us to find out what it means. Any body have a clue, I was wondering about doppler.

Answer 1

yep

Answer 2

red is low frequency, violet is high frequency
If you see a shift from red towards violet, the radiator is moving toward you fast so you see a higher frequency than the radiator radiates.
If you are standing at a train station as a train goes by making a noise, you hear a high frequency as it approaches and a lower one the instant it passes and starts moving away from you.
The T shirt person was not only moving fast but also was headed for the teacher.
In astronomy, the red shift means that the light we see from a start is shifted toward lower, red, frequency because it is moving AWAY fast.