I have this more-expensive-than-my-car hunk of metal on loan for the next few weeks. It’s a pretty far cry from the old Tektronix analog scopes I trained on back in the day (which, at the time, were also much more expensive than my then-primary mode of transportation: shoes). As a warmup exercise, I hooked it up to the output of my guitar amplifier and played an A, which you can see pictured. You can also see that I’m apparently tuned down a half-step as the frequency measured on the scope is about a semitone shy of 220 Hz.
This was a neat teaching opportunity for my four year-old: I showed Alex visually that sound is just made up of different kinds of waves. Later at bathtime he connected that with the physical waves he was making in the tub: “Just like music!” he said.