The original hands-on science gallery has had a £4m transformation. Take a trip to London's Science Museum and you will find a few surprises.

Its most popular gallery, the Launchpad, has moved and almost doubled in size and sophistication. More than 50 interactive exhibits have been built to entice young visitors and excite their imaginations.

The gallery is particularly aimed at eight to 14-year-olds. On the day I visited there were plenty of siblings as young as three having a great time in the Grain Pit even though The Garden in the basement is designed for two to seven-year- olds.

I took my grandchildren with me and, if their reaction is anything, I would recommend arriving soon after the museum opens at 10am.

A visit will introduce young visitors to the principles of magnetism, forces and motion, energy transfer, light and sound.

The water rocket launches a plastic bottle 30m across the gallery using just air pressure. My grandchildren particularly enjoyed the echo tube, wiring up a burglar alarm and, of course, the pulleys.

There are regular shows and we attended The Bubble Show. It was, like the Launchpad itself, pure entertainment but the children also came away having learned a new word molecule'. The other performing science show is called Danger! High Voltage.

It is possible to spend the whole day in this gallery but there are plenty of hands-on activities to be enjoyed in other parts of the museum too.

Admission is free. The only charges are for the simulator rides and the Imax where the screen is taller than a double-decker bus. One programme reveals the magic of the deep sea in a 3D film narrated by Johnnie Depp and Kate Winslet.

There are still the icons of the industrial revolution to be seen, of course, such as the first steam engines and Stevenson's Rocket on the ground floor. The museum was established with the profits from The Great Exhibition of 1851 when that technology was cutting edge.

The Science Museum is open 10am-6pm daily and the nearest tube station is South Kensington. For more details visit the www.sciencemuseum.org.uk website.