Merriam-Webster defines rhythm as: the aspect of music comprising all the elements (such as accent, meter, and tempo) that relate to forward movement
The last two words of this definition “forward movement” are the key to really understanding rhythm. Let’s perform a short thought experiment: take your time and try to imagine a piece of music without any rhythm. What does it sound like? How would it be possible for any element of the piece to change without rhythm?
The simple fact of the matter is without rhythm all music would either be constant, unchanging sound, or total silence. Another way to think about rhythm is it is where the element of time is introduced to music. As long as something changes over time there is rhythm.
Here’s a breakdown of how rhythm is notated in standard music notation:
The notes above are arranged from longest to shortest. As we move from left to right each note duration halves in length. So 2 half notes equal the same duration as 1 whole note, 2 quarter notes equal 1 half note, 2 eighth notes equal 1 quarter note, etc…
One might notice that the name of the notes correspond to fractions: 2 halves, 4 quarters, 8 eighths, and 16 sixteenths all make a whole. This can be a useful shorthand to remembering how these durations fit together.
Musical meter gives us a structured way to organize music over time. There are pieces that exist without meter, but those are few and far between. Meter divides music into regular chunks, called measures, the length of these measures can change throughout the course of the piece, but, in most cases, the meter unifies all of the musicians in an ensemble on the same page.
We notate meter with two numbers. The top number describes how many beats are in each measure while the bottom number describes what counts as a beat. Here are some examples:
The final piece of the puzzle is tempo. Tempo is the speed at which notes progress. Typically, we measure tempo in beats per minute, however, it’s not uncommon to see general guidelines for tempo such as “Moderato” or “Allegro.”
Tempo can also be changed in the middle of a piece in a few different ways. We’ll cover these more in depth at a later time, but for now keep in mind that both tempo and meter can be altered at any time during a piece of music.