Question: What are the bottom notes of the piano?Adrianna (Texas, USA)
Albert's reply: Assuming you're using a standard full-sized, 88-key piano, the bottom key plays A.
Always remember that the keys are not the notes. Since each of the piano's keys has to be tuned to a specific pitch, each of those pitches will approximate a musical note.
Depending on how the piano is tuned, some notes will be more exact than others. Since most pianos nowadays are tuned to equal temperament, this means that all musical keys (not to be confused with the piano's keys!), such as C major and B-flat minor, are equally out of tune. Still, they are all "close enough" to the correct pitches that each key still sounds good.
That bottom key, then, could also play other equivalent enharmonic notes (in this case G double sharp and B double flat), but these notes are rare enough that you almost never encounter them in actual music. That's not the case for many of the piano's other keys, however! This is why it's critical to differentiate between the piano's keys and the notes they play.
Interestingly, some grand pianos by the prestigious Bösendorfer company in Vienna, Austria extend further than A. Their model 225 goes down to F, while their gigantic Imperial has fully nine extra keys, reaching all the way to sub-contra C!