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Why does my head hurt so much after I eat ice cream too quickly? Leon Groom

In 2002, Professor Janusz Kaczorowski of McMaster University, Canada and her daughter, Maya, 13, set out to establish the prevalence of 'Ice Cream Evoked Headaches' (ICE-H) among secondary school pupils eating at different speeds.

In the study, published in the British Medical Journal, 27 per cent of students who wolfed down 100ml of ice cream in under five seconds reported ICE-H, comparedwith 13 per cent in thegroup who took 30 seconds or more.40 per cent of these reported "brain freezes" ceased within 10 seconds.

The reaction, known as frozen brain syndrome, or spheno palatine gangleoneuralgia, is triggered when a very cold substance makes contact with the roof of the mouth. Assuming a sudden drop in outside temperature, the body responds by constricting the vessels in the head, reducing blood flow in an effort to minimise heat loss. The dilation of these vessels causes the nerves in the palate to send pain signals to the brain.

The cure? Abstinence, slower ingestion or, in an emergency, firmly applying the tongue or thumb to the roof of the mouth.

Why does the moon look so huge sometimes? Mary Landry

The distance between the earth and the moon is a fairly constant 239,000 miles, yet on a clear night, when a full moon is low in the sky, it can appear impossibly large.

One theory, called the Ponzo Illusion, suggests that the brain judges the size of an object based on what surrounds it. In 1913, Italian psychologist Mario Ponzo demonstrated this by laying bars of equal size over an image of railway tracks disappearing into the distance. The higher bar seems larger because it spans the tracks. The lower bar sits within the tracks, so our brains assume it is smaller. The theory says trees, buildings or roads act in the same way to 'enlarge' a low moon.

Alternatively, the flat sky theory posits that our brains perceive the sky as a flattened dome rather than a hemisphere, so we perceive objects directly overhead to be closer than those on the horizon. When we see a low moon, our brains miscalculate its true size and distance.

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