Follow your curiosity

What discovery has been shared with you?

FACTREE gives you something interesting to discover every day — and something worth talking about together.

Start with one fact. Explore it, go deeper, then follow whichever branch catches your imagination.

Choose subjects for a surprise

Exploring any topic

Begin your discovery

Your next discovery is one click away.

Choose one or more subjects above, or leave Any Topic selected and let curiosity decide.

Physics

Frequency Spectrum

Quick fact

When sunlight passes through a prism, the rainbow you see is actually the frequency spectrum of visible light—and beyond both ends lie invisible infrared and ultraviolet frequencies.

Why this is interesting

If you press a single key on a piano, you hear a pure tone—but when you listen to a chord, how does your ear separate the notes? The answer lies in the frequency spectrum, a hidden map of every sound's ingredients.