Science of celebrations The formula for a 'magical' Christmas

Christmas may seem like a time for switching off and suspending disbelief, but there are plenty of ways to introduce a little science into the celebrations.

- Nicola Davis Science correspondent

We asked experts for their top home experiments to challenge friends and family.

Sweet science Matthew Cobb, professor of zoology at the University of Manchester, suggests picking a sweet such as a jellybean and, with your eyes shut and holding your nose, chew it, all while keeping your mouth shut.

"See if you can tell what the sweet tastes of - you will probably just say 'sweet' and maybe have a vague idea of something else," said Cobb. "After five seconds, take your fingers off your nose and you should get a sudden rush of sensation that enables you to correctly identify the flavour." A more extreme version of this experiment, he said, involves grating an onion and an apple, separately, then tasting each of them on a spoon with your eyes shut and your nose firmly held: "They should taste the same, until you take your fingers off your nose." Cobb said such experiments showed how flavour was largely composed of smell, not taste: "When we chew, the smells emitted by the food go up into our nose via the back of our mouth, where they stimulate our olfactory neurons."