Lab v
A bar of music is a whole pizza. Cut it in halves, quarters, eighths — or threes — and turn each slice on or off while the beat sweeps by.
one bar, five ways to slice it — tap a slice to turn it on
read it on a stave — pick a row
One line, one pitch — so the only thing on the page is time. A slice you switched on is a note; a slice you left off is a rest, which is silence written down and counted just as carefully. 4 of the 4 quarters slices are on. The triplets row is missing on purpose: dividing the bar by three needs a tuplet bracket, and we would rather leave it out than write it wrongly.
one bar lasts 240 ÷ 100 = 2.40 s
Every row is the SAME bar of time. The quarters row cuts it into 4 equal pieces; the eighths row cuts it into 8. Two eighths fit exactly inside one quarter — that's 1/8 + 1/8 = 1/4, and you can hear it.
The triplets row cuts the bar into 3 — and 3 doesn't fit neatly into 2, 4 or 8. Its slices land between everyone else's. That in-between feel is called a triplet, and drummers love it.
Press the “3 against 2” button. Halves click 2 times, triplets 3 times — and they only land together at the very start of the bar. They next meet after 6 little slices, because 6 is the smallest number both 2 and 3 divide into: the LCM. Polyrhythm is LCM you can dance to.
For the classroom