Beyond the answers - interesting background to this quiz

A pauper's tale that refuses to age

Mark Twain published The Prince and the Pauper in 1881, and it was a departure from the river adventures he was best known for. The novel imagines two boys born on the same day in sixteenth-century London who look identical but come from opposite ends of society: Tom Canty, a poor boy from Offal Court, and Edward, the Prince of Wales. They swap clothes as a game, and the exchange becomes permanent when neither can prove his identity. Twain wrote it partly as a historical novel for younger readers, but its themes of poverty and justice are unmistakably his own.

Nicosia, a capital split in two

Nicosia sits near the centre of Cyprus and has a history stretching back well over a thousand years. What makes it unusual among European capitals is that it is divided: a buffer zone, often called the Green Line, runs through the old city and separates the Greek Cypriot south from the Turkish Cypriot north. The city also has Venetian walls, built in the sixteenth century, that still trace a star shape around the historic centre. Few capitals reward a slow walk quite so much.

Oganesson and the end of the periodic table

Oganesson takes its name from Yuri Oganessian, a physicist honoured for his work on superheavy elements. It occupies position 118, the last slot in the current periodic table, and its symbol is Og. The element is extraordinarily unstable: only a handful of atoms have ever been produced, and they decay within milliseconds. Because so few atoms exist, much of what scientists predict about oganesson comes from theory rather than direct observation.

The Scoville scale, born in a laboratory

The Scoville scale dates back to 1912, when the American pharmacist Wilbur Scoville devised a test to measure the pungency of chilli peppers. His method relied on a panel of tasters who diluted a pepper extract until they could no longer detect any heat. Modern labs use chemical analysis instead, but the results are still expressed in Scoville Heat Units. The ghost pepper, a hybrid chilli from north-east India, has registered over one million units, while a bell pepper sits at zero.