Why Are Orangutans Orange?, Edited by Mick O'Hare

You might think that a query about why the "N" was the only one to be frost-free on a MONDEO car emblem, or why red cabbage juice turns green when dripped on a fried egg, would only be of interest to a tiny minority, but you'd be dead wrong. The questions about such quirky phenomena posed by readers in the New Scientist's "Last Word" column and answered by other readers have a massive appeal. Previous collections of these Q&As, such as Why Don't Penguins' Feet Freeze? and Does Anything Eat Wasps?, have sold two million copies.

The latest in the series is destined to do equally well, if only because the inquiries are illustrated for the first time. Interestingly, the gruesome green splat on a fried egg was due to red cabbage juice acting like litmus paper when in contact with the alkaline fried egg. Less interestingly, the frost-free "N" resulted from "poor thermal contact" because the letter was loose.

The photographs add a new layer of interest. A furry blue brick turns out to be a mouldy bar of soap discovered in Sardinia. "Traditional soap consists of fatty acid salts [and] is completely digestible in small quantities," offers a reader. A drop of spilled milk doesn't sound interesting until you see the photo of 18 small droplets surrounding a larger droplet in a perfect circle. "The study of splashes has a long and distinguished history," a reader replies, before going into detail about the "corona splashing" that produced the circle.

Some questions provoke dissent among respondents. Found on a Lake Michigan beach, sand forms like inverted mushrooms might be worm excreta, raindrop patterns or "urination concretions". A gooey bubble found in Scotland is variously explained as fungus, unfertilised frogspawn, frozen human excrement from a plane, a sea squirt or "the pupa of a haggis".

The book often jogs your memory about odd things you've seen but instantly forgotten. The airplane jet sucking up ground water is acting like a tornado. The long line of creepy-crawlies are pine processionary moth caterpillars, once only found south of the Loire but now heading north. A chapter on clouds includes some gorgeous images, but the reader who sent in a picture of a formation known as manna ("the Latin word for breast") is accused of digital manipulation. And the orange of orangutans? Camouflage.