How did we know? The first clues came from looking at one of the simplest electricity experiments you can do on Earth, involving an electroscope. If you’ve never heard of an electroscope ...

Inside the chamber is an electroscope, consisting of a flexible quartz fiber and a fixed electrode, and a microscope with a calibrated reticle. When a high voltage is applied to the electrode ...

Another fun way of observing the charging and discharging in action is to place the terminal of an electroscope near an inductor or receiver. As the charge builds up, the electroscope leafs will ...

but detected only by the electroscope, a “spectrum” of definite lines for certain elements can be obtained. By arranging now the elements according to the first line of these X-ray spectra ...