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

Diffraction of Sound Waves

Quick fact

Sound waves can bend around a person's head, which is why we can still hear someone even when they are behind us—a form of diffraction around a comparatively small obstacle.

Why this is interesting

Have you ever heard someone talking from around a corner before seeing them? How does sound sneak around obstacles when light cannot?