There are a number of jokes about mathematicians, physicists, and engineers playing with their balls. Here are three variants.

#### Little balls

A mathematician, a physicist and an engineer were undergoing a thought-process experiment. As part of the experiment, they were given 2 brass ball bearings and left alone for a while. After an hour or so, the experimenter returned to each of the three professionals and asked what they had done with the 2 ball bearings.

The physicist replied: “I’ve tried to balance one on the other, and have some ideas about friction.”

The mathematician, rather sheepishly, admitted “I haven’t done anything with them.” But then he excitedly added, “but I’ve some theories about two-ness.”

The engineer shrugged. “They broke.”

#### Midsize balls

A mathematician, a physicist and an engineer were undergoing a thought-process experiment. As part of the experiment, they were seated at a table, given 3 metal spheres, and left alone for a while. After an hour or so, the experimenter returned to each of the three professionals.

He checks in on the mathematician first, and finds the balls neatly arranged in a triangle at the center of the table.

He checks in on the physicist next, and finds the balls stacked precariously, one on top of the other, in the center of the table.

He then checks in on the enginner, and finds one of the balls is broken, one is missing, and the third being carried out in the engineer’s lunchbox.

#### Big balls

A mathematician, a physicist, and an engineer are all given identical rubber balls and told to find the volume. They are given anything they want to measure it, and have all the time they need.

The mathematician pulls out a measuring tape and records the circumference. He then divides by two times pi to get the radius, cubes that, multiplies by pi again, and then multiplies by four-thirds and thereby calculates the volume.

The physicist gets a large bucket of water, places 3 gallons of water in the bucket, drops in the ball, and measures the displacement to six significant figures.

The engineer writes down the serial number of the ball, and looks it up.