Chemistry, made learnable
Study guides for the class everyone says is hard.
Guides and explainers for students and the parents helping them: how to memorize the periodic table, why you blank on tests even when you studied, and how to walk into chemistry with a head start.
Greenland Shark Lifespan: How Do We Know?
Greenland sharks can live at least 272 years. Scientists put the largest at 272 to 512 from the carbon-14 in its eye and its length. How sure is that?
Explainer · 12 min read →
How Accurate Is Carbon Dating?
Scientists can carbon-date things up to 50,000 years old, usually to a 120–200 year range at 95% confidence. How it works, its limits, famous cases.
Explainer · 15 min read →
Helium Was Discovered on the Sun First
Helium is the only element found in space before Earth. Astronomers saw its yellow line in an 1868 eclipse, and chemists found it here 27 years later.
Explainer · 6 min read →
When Aluminum Was Worth More Than Gold
In the mid-1800s aluminum cost more than gold, because no one could free it from its ore. Then two young inventors did, and the price collapsed.
Explainer · 6 min read →