xkcd #3094: Mass Spec

Title text:

Patients at least found it to be an improvement over Millikan's incredibly messy and unpleasant oil drop suspension procedure.

Transcript:

[Ponytail, wearing a lab coat, is giving a balloon to Cueball. Behind Cueball, there is a ramp on the ground, a magnet hanging from the ceiling, and a target on a poster on the wall.]
Ponytail: Rub this balloon against your head, then go jump past that magnet toward the target on the wall.

[Caption below the panel:]
Before the bathroom scale was invented, the only way to weigh people was mass spectrometry.

Source: https://xkcd.com/3094/

explainxkcd for #3094