Nothing Is Waving

You'll learnwhy light crosses a vacuum that silences a bell, what actually oscillates in an electromagnetic wave, and what orders the spectrum from radio to gamma.

Pump the air out of a jar with a ringing bell inside and the sound dies — but the bell stays perfectly visible. What carries the light out when nothing is left to wave? Twelve short steps; press Next for each one.

12 STEPS · 6 QUICK CHECKS · FIELDS, NOT MATTER · ORDERED BY WAVELENGTH · v2

fields oscillate, not matter · the spectrum is ordered by wavelength

Before you start

What you're looking at

A bell jar with a ringing bell and a lit lamp inside, about to be pumped empty of air.

The question

What is actually oscillating in a light wave — and what decides where a band sits on the electromagnetic spectrum?

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