Today, Google has as its logo a very audio-related thing. Did you recognize the moving waves? That's what audio "looks" like. The logo is in honor of the birthday of Heinrich Hertz, who proved the existence of electromagnetic waves. His work was mainly about light waves, but audio waves are very similar.
You've probably heard the term "hertz" before, and maybe not even when speaking about rental cars. In the audio world the term is so common that we don't even bother spelling it out anymore. It's just "Hz." You've probably been prompted for it at some point by a computer asking if you'd like your audio file to be saved as a 44.1 KHz. Or you've seen articles here about EQ where I say things like "you can reduce sibilance by lowering settings around 6 KHz."
Maybe you can remember a math or physics class talking about wave mechanics. Pretty much any field where we use the concept of cycles-per-second, which is what "hertz" has come to mean, good old Mr. H is right there in the thick of it.
In music we describe pitch in terms of cycles-per-second. Ever wonder what "A440" (the standard reference for tuning an instrument) means? The 440 stands for the number of cycles per second of a sound wave to make it sound like an "A" note to our modern ears. It's used in cell phones to describe the carrier frequency, radio, video, audio, magnetics, you name it, Heinrich is there.
So if you were wondering how today's Google logo related to you, now you know!