Beyond the answers - interesting background to this quiz

The calendar's quiet exception

Most of us learn the rhythm of the months through the old rhyme about knuckles and gaps, but the reason February is short and April, June, September and November have 30 days goes back to the Roman calendar. The months were reshaped over centuries, and the lengths were fixed to fit a solar year of roughly 365 days. February ended up with the fewest days precisely because it was the month left over after the others were assigned.

Why 88 keys became the standard

Pianos were not always built with the same range. Early instruments had far fewer keys, and the number grew as composers demanded more notes. By the late 19th century, 88 keys - just over seven octaves - had become the standard for most manufacturers, and it has stayed that way ever since. That range covers nearly all the music written for the instrument.

The science behind the forecast

Meteorology is the study of the atmosphere and the processes that produce weather, while climatology looks at longer-term patterns. The two are related but distinct: a single storm is a weather event, while the statistics of many seasons describe climate. Modern forecasting relies on vast computer models that simulate the atmosphere, which is why a five-day forecast is far more reliable than it was a few decades ago.

A gift across the Atlantic

The Statue of Liberty was a gift from France to the United States, designed by sculptor Frederic Auguste Bartholdi with an internal framework engineered by Gustave Eiffel. It was dedicated in 1886 and has stood in New York Harbor ever since. The copper skin has gradually weathered to its familiar green patina, a change that took decades to complete.

Measuring gold's purity

Pure gold is measured as 24 carats, meaning 24 parts out of 24 are gold. Anything lower is an alloy, mixed with metals such as copper, silver or zinc to make it harder and more durable for jewellery. An 18-carat ring, for example, is 18 parts gold and 6 parts other metals - a compromise between purity and strength that jewellers have used for centuries.