Shake it, turn it over, wait a second, read the answer. The mechanism behind that is simple enough to explain in a paragraph, and it has barely changed since the toy went on sale in the 1950s.
The parts
- The outer shell. Hard plastic moulded to look like a billiard eight ball, with a flat window on the bottom.
- An inner cylinder. A sealed tube of liquid that sits behind the window. The shell exists mostly to hold it and to look right on a desk.
- The die. A white icosahedron, twenty triangular faces, each carrying one answer.
- The liquid. Alcohol dyed dark blue, thick enough to slow the die down.
Why the answer rises so slowly
That pause is deliberate. The die is a little less dense than the liquid, so it floats up; the liquid is viscous, so it floats up gently. The delay does two things: it gives the die time to settle on a random face, and it turns a coin flip into a small piece of theatre. Without the delay you would have a plastic ball that answers instantly and feels like nothing.
The dark dye hides the die until it reaches the window, so the answer appears out of nothing rather than being visible on its way up. Bubbles are the enemy of the effect, which is why the cylinder is filled to leave as little air as possible.
Is it random?
Effectively yes, though not perfectly. A twenty-sided die tumbling in fluid lands close to evenly across its faces, so each answer has roughly a one in twenty chance. Because ten of the twenty faces are positive, the ball skews cheerful: about half of all answers are some form of yes, a quarter are negative and a quarter are the non-committal replies. Read our piece on the twenty answers for the full split.
If you open one
People do, usually with a saw and usually once. Inside you find the cylinder, the blue liquid and a slightly grubby die that looks much smaller out of the ball than it did through the window. The liquid is alcohol-based, so keep it away from children and pets, wear eye protection if you are cutting, and expect the toy to be finished afterwards. There is no way to reseal it cleanly at home.
A ball that has gone cloudy or full of bubbles has usually been left in the sun or dropped hard enough to let air in. Neither is repairable, though storing it upright and out of heat prevents both.
Fortune telling or toy?
It is a toy, and its makers have never claimed otherwise. The interesting part is that it works the way a coin flip works: the answer matters less than your reaction to it. If you want an actual conversation about a decision rather than a random face on a die, our fortune telling listings show who works in your city and what clients say about them.