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

Wave Refraction

Quick fact

Refraction causes the apparent depth of a swimming pool to be shallower than its actual depth; light bends when leaving water, tricking your eyes.

Why this is interesting

Have you ever noticed how a straight stick looks bent when you put it in a glass of water? That's the same effect that makes waves change direction as they move from deep to shallow water.