Physics · Study 016
Newton's Cradle
Five steel balls on strings trade momentum end to end. Click to lift one, two, three or four balls and see the same number leave the far side.
What you're looking at
Lift some balls on one side, let go, and the same number swing out on the other while the middle stays still. Only that outcome conserves both momentum and kinetic energy at once for equal masses in a row, so that is the one nature picks.
The idea behind it
Inside the row, the collision travels as a compression pulse through the steel at several kilometres per second. The toy is named for Newton because it illustrates his laws so cleanly, though the desktop version dates from the 1960s.
Try this
Click or tap to change how many balls are lifted, from one up to four.
