Has everyone brought their hands today?” A sea of hands duly waggles in response to this question. “Good. If you have any questions, please ask. And remember, no running.”

As the Science Museum’s “explainer” finishes her first explanation of the day, a group of young children are already on their feet. Decked out in bright orange and green road-maintenance waistcoats, they tear off through a curtain of yellow tubes just as soon as someone has rolled up their sleeves.

They are making for the Garden, a gallery in the basement of the museum designed especially for three to six-year-olds. It opened in 1995, and aims to introduce very small children to their first science lessons, by encouraging them to use their senses. Its particular appeal lies in the fact that all the exhibits are interactive. There is nothing to just stand and stare at. You simply have to get your hands out to explore.

Empty, the room looks like a trendy bar and was designed by Ben Kelly, who is renowned as a creator of night clubs. There are yellow poles and purple walls and benches in ergonomic shapes that could be straight from the pages of a design magazine, arches and a bright red skip with portholes to climb in and out of.

It is not just infants who can benefit. The designer has been very conscious of children who might have special needs. So those with learning or physical disabilities will find they are able to do just as much as able bodied children and there is disabled access throughout.

The teachers who are accompanying a group of would-be scientists watch as their charges are wholeheartedly engaged, without any prompting or guidance from them.

“The Garden provides a concentrated experience of the main scientific concepts,” one teacher explains. “Much of the national curriculum is covered here and there are more interesting illustrations of the concepts we teach at school.

“Crucially for the children, everything is on a far grander scale than we can provide in a classroom. They think this is fun, which is a very important factor for children of this age.”

One of the exhibits is a large tank in which to explore ways of moving water. With containers, blocks of plastic and pumps, children scoop, dam and send air bubbles whooshing through the tank.

In a stainless steel sink, in an alarming display of gender stereotyping, the girls are hard at the washing up, while the boys are busy sinking ducks.

“Roll up your sleeves, please David,” one teacher urges. But it is too late. David has forgotten an essential quality of water - that it is wet - and plunges his arms in to his elbows, soaking his jumper.

“Explainers” are always on hand to help get children started with some of the exhibits, and soon there is a band of boys engaged in an ambitious construction project involving a pile of plastic blocks, a nest of tubes and a Romanesque arch.

Nearby, there is a pulley with a sack attached to a piece of rope which one boy is loading with bean bags: “Put the gold in here,” he tells his friends holding open the swag bag. “And we can hide it up there.” The science lessons may not be too obvious, but the children are clearly learning something.

In front of trick mirrors, two girls twist themselves into contorted shapes, amid paroxysms of laughter. Behind them a classmate sits repeatedly on a bench which makes the sound of a cock crowing.

Outside the Garden, another school party is already queuing up. It’s like the countdown at Cape Canaveral: “Two minutes, everybody,” a voice says, “and we’re going in.” Inside, the others are beginning to flag. “Can we hang our waistcoats up, please?” asks one, who’s clearly had enough science for one day.

As the children file out, an “explainer” briefs a colleague on the explanatory introduction: “Tell them it’s where science comes alive.”

* The Science Museum, Exhibition Road, London SW7 2DD. Education office, tel: 0171 938 8222. Open 10am to 6pm seven days a week. Book the Garden in advance.