The answer is CH3CH2CH2CHO
Adding perchloric acid to water would cause it's conductivity to increase.
It knows that when water evaporates, it carries heat energy away with it.
So your body puts some water out on your skin, and hopes that it will
evaporate. We call that "perspiring" or "sweating".
Reflection, refraction, and diffraction
Reflection occurs when waves bounce back from a surface that they cannot pass through. Refraction occurs when waves bend as they enter a new medium at an angle and start traveling at a different speed.