Tukuk-OSThe Knowledge Complex
Daily facts, riddles, experiments, geography, history, math and tools — free, no account, every day fresh
One place for curiosity: verified facts, real experiments and quick brain training — every section is free, needs no account, and rotates its daily picks on the calendar. For deeper structured learning try the Zero-to-Hero Academy or the NASA Space Complex.
Today, in four cards
📅 Today’s fact
A single lightning bolt can heat the air around it to roughly 30,000 °C — about five times hotter than the Sun's surface.
🤔 Riddle of the day
What can go through a glass window without making a hole in it?
Show answer
Light.
🪺 Experiment of the day
Yarn DNA extraction — about 30 min.
Soap and salt break cell and nucleus membranes and pull DNA out of its proteins; DNA does not dissolve in alcohol, so it crashes out as visible strands.
📜 History moment
AD 79 — Vesuvius buries Pompeii
The eruption preserves a Roman town in ash — streets, bakeries, graffiti — an accidental time capsule of ordinary empire life.
Eleven ways to explore
Each section below is a full standalone page — read it, play with it, or use it for classroom and family curiosity.