The precise science of a great sleepover party

Not many people have slept in space. But every month more than 100 children lie in the darkness gazing at the the Apollo 10 Command module.

Fiona Macaulay joins Science Night at the Science Museum in London.

The excitement is palpable as children between the ages of eight and 11 arrive for an evening of activities at the Science Museum, after which they bed down in sleeping-bags in three of the main galleries; Space, Power and Shipping. The idea of sleepovers in museums originated in the United States in the Seventies. The Science Museum broke the ground in Britain in 1993 and since then a few others have followed suit, most recently the British Museum.

At the Science Museum, each sleepover night has a theme, such as Stars and Space, or Travel and Journeys. The one I attended was themed on the senses. Children come in groups of between five and 30, with an adult accompanying every five children of the same sex.

When the hordes arrive the first thing they do is set up camp. Boys and girls are separated into "dormitories". On the night of my visit the boys' side was a scrummage of sleeping-bags that had been hastily dumped down. The girls, however, laid out pyjamas in neat piles on their pillows, alongside cuddly toys.

Once bivouacked, the children can look round the galleries or participate in the "Science Stops", a series of small, hands-on experiments. They powered a propeller into flight by attaching it to a deflating balloon, and a tin bird was made airborne by an elastic band mechanism.

Then the welcome and safety talk began. This may sound rather dull, but it is in fact where the theatrical part of the evening starts. We met SAM, the Safety Android Mechanism, dressed in a silver space suit. He spoke to us in a strange sci-fi dialect and warned us that if we did not heed him,"it might result in removal of my powerpack and my being melted down to make a vacuum cleaner".

The next theatrical experience was listening to a scientist, Peter Barham, explain to us about illusions: "Things are not always what they seem."

This was made clear through a series of simple experiments, one of which involved sticking labels on our foreheads and trying to write the word "speed" on them, which resulted in an assortment of strange mirror-writing characters.

An Inspector Clouseau-type character was the star of the next part of the evening, entitled "Solve It!". Dressed in belted raincoat and trilby hat, she stalked amongst the audience to reveal the facts of a crime. We were told that an object had been stolen from the museum and that we must discover what it was, where it had been stolen from and the route that the thief took to escape. The only clues were those provided by a visually impaired witness, Miss Philpot. Using our senses, excluding sight, we tried to decipher the answers from her story.

After taxing our brains in this session we then had to exercise our manual skills to make our own camera obscura. I was completely taken aback to find that this could be achieved with no more than a cardboard tea box, a piece of tracing paper and some Sellotape. During this workshop it was also explained how the eye sees, and the way in which the camera obscura mimics this process.

Theatricals returned for the final event of the evening. The backdrop was the spectacular Flight Gallery, where "birdmen", balloonists and some of the world's most historic aeroplanes are suspended from the ceiling.

In this darkened, cavernous hall everyone was gathered together for the first time, and the excitement was electric. I wondered how any of these children were ever going to settle down to sleep.

Above us on a raised walkway appeared an actor dressed for arctic conditions as the legendary Clarence Birdseye, pioneer of mass-produced frozen food. He talked about survival techniques at sub-zero temperatures and the Inuit people: "Eskimo means raw-flesh-eater. That's not a very nice name to call someone. They call themselves Inuit, meaning super-race."

Amazingly enough, the children did go to sleep quite quickly after this. Apparently that is not always the case, and the adult contingent can be kept awake till the early hours of the morning.

After breakfast the next morning it was back to the spectacular flight gallery for a quiz trail on the history of flight. This was a good way of starting the day, as there was lots of space to wander round in your own party without bumping into other people. Plenty of time was given to having a good look around and to completing the answers.

Thank goodness for the gentle start (not that the children seemed to be bothered) before our visit to "Launchpad", where we were to be "launched into science". Never have I seen so much frenetic activity so early in the morning as there was in this diverse, hands-on gallery. Bodies struck dramatic poses in the "Shadow Box" when a light flashed, leaving dark shadows against a luminous green background on the screen in the cubicle. This is because the phosphors on the screen store up the energy of light. Others crept along the "Tiptoe Tester" (a vibration detector) or powered by hand a grain pit which lifts the corn by turning an Archimedes screw.

There are so many different things to try at Launchpad that after a three- quarter-hour session the children almost had to be frog-marched out, so reluctant were they to leave. Taking a straw poll amongst the children, this came out as a favourite, along with the mind-twisting "Solve It!" session.

Finally, prize-giving brought everything to a close, with books awarded for the best drawings of the evening and for the winners of a quiz on the night's activities. After this official end to science night, the children were allowed to stay in the museum for the day, with the bonus of free admission to the new Science of Sport exhibition. Relief troops of parents began to arrive to take over their still-energetic charges, and to hear excited chatting about the night's events. I admitted defeat, and went home to bed.

Science Night takes place once a month and costs pounds 20 per child and pounds 18 per adult. For details contact the Science Night Office at the Science Museum on 0171-938 9785.