Blog
Why is a rainbow curved? Why does a magnet stick to the fridge but not to wood? Short, sourced, clear articles.
When wood burns, only a handful of ash is left, yet a rusting nail gets heavier. Does mass vanish, or appear out of nowhere? We explain the law of conservation of mass, Lavoisier's experiments and how to balance chemical equations.
7 min read
The golden ratio is said to be hidden in the pyramids, the Parthenon, the Mona Lisa and the human face. Most of these claims aren't based on measurements. We sort out the real maths of the golden ratio and where it truly appears in nature.
7 min read
How does our body fight germs, and why does a vaccine protect us for years? We explain the immune system, antibodies and memory cells, the types of vaccine and herd immunity in plain language.
7 min read
Reading a topic over and over makes us feel we have learned it, but lasting learning takes a different route. We explain two of the most solid findings in cognitive science, the testing effect and spaced repetition, and how to apply them to everyday study.
10 min read
Why does February sometimes have 29 days? Why does Ramadan come about 11 days earlier each year? What do the Rumi dates in old Ottoman documents mean? We explain the astronomy and history behind calendars in plain language.
7 min read
Why do we see the lightning first and hear the thunder later? We explain how sound travels, how fast it moves through air, water and steel, and how a simple calculation tells you how many kilometres away a storm is.
8 min read
The difference between simple and compound interest looks small in the first years, but over time it grows surprisingly large. We explain the maths of exponential growth, the rule of 72, the effect of inflation and the story of the number e, with examples.
10 min read
Today we can't imagine life without zero, yet for thousands of years people did their sums without it. We tell the story of zero, from a gap marker in Babylon to a true number in India, and from Baghdad to Europe.
7 min read
Why is lemon sour and soap slippery? We explain what acids and bases are, how to read the pH scale, why each pH step means a tenfold change, and how to make a natural indicator from red cabbage.
7 min read
A young woman who studied in secret classes in Warsaw went on to process tonnes of ore in a shed in Paris and find two new elements. We tell the story of Marie Curie's life, the discovery of radioactivity and its cost.
7 min read
What is DNA, and how is a gene different from a chromosome? We explain the basics of heredity with Mendel's peas, show with real genetics why eye colour is not as simple as people think, and extract DNA from strawberries.
7 min read
In a class of 23, the chance that two people share a birthday is over 50 per cent. After five heads in a row, are tails now due? We work through two classic examples that fool our sense of probability, with the calculations.
10 min read