How long can you hold your breath under water? Apparently 30 seconds is the norm, or two minutes if you're a pearl fisher. Sperm whales can do it for hours, it seems.
Jersey's Maritime Museum, which opened last year, seems to have the answer to every possible question you could think of about the sea and ships. Most importantly, everything is displayed imaginatively in a way which seems designed to entertain more than educate but succeeds brilliantly at both.
Housed in former customs warehouses on the quay in St Helier, the museum covers the three main aspects of the sea: Elements, Ships and People. Each section has plenty of artefacts as well as gadgets to operate, interactive video screens, models, paintings, photographs and historic newspaper cuttings.
"Our designers' aim was to create a traditional but absorbing museum, rather than follow the trendy design-led style of many new ones," says Jon Carter, the curator.
Gaps in the collection have been filled by items specially commissioned from local artists and craftspeople rather than with computer simulations. For in-stance a colourful ship's figurehead was produced from a design used for a ship built locally in 1861.
"We want everything to be visually striking," he says. "There is so much information on display that every exhibit has to look entertaining and intriguing if visitors are to absorb it."
So visitors may find themselves lingering over displays on subjects which may not sound particularly alluring, simply because they are so vividly presented.
The diving exhibits, for example, include a pile of rubbish collected from a local beach as part of a display about pollution. Nearby, a small jar of oil is labelled with a warning that it would cover an area the size of a football pitch if poured into the sea. And who would have thought that a plastic bottle carelessly thrown from a ship could take as much as 450 years to disintegrate?
At the push of a button, the cycle of the tides is demonstrated in a large tank, and there are models which you can activate to test the resistance of water. It came as no surprise to find that fish shapes sink fastest.
In the Elements area, bottles of water from the Dead Sea, English Channel and a river reveal the huge differences in their salt content. Overlooked by giant iron crabs, a working model demonstrates how sand builds up when blown by the wind.
By way of introduction to the Ships and People areas, you pass through a gallery with portholes overlooking a workshop where hulls are being repaired. This island thrived on its ship-building trade during the last century until wood and sails were displaced by metal and steam.
Beside walls of photographs and paintings, a ramp leads down to a huge open metal globe which has four large levers to pull. Each sets a model sailing ship off around the world, while a voice tells the story of an actual voyage from Jersey.
Using wooden blocks and little canvas sails, you can make a simple model boat, put it in a tank of water and start the wind machine to blow it along.
There are photographs and biographies of famous Jersey sailors and you can listen to Jersiaise, the old Jersey language. A touch-screen helps you try to understand what is being said.
Inside a full-size replica of part of the hull of a wooden sailing boat, you get an idea of what conditions at sea have been like in the past. As you walk into the captain's cramped cabin, it rolls as if out on the waves. If you are prone to sea-sickness, you might not want to spend long in here.
The museum building also houses the Occupation Tapestry, which vividly depicts life on the island when it was occupied by the Germans from 1940 to 1945. The 12 large colourful panels were sewn by islanders to commemorate those harrowing years.
The Maritime Museum and Tapestry Gallery, New North Quay, St Helier, Jersey. Tel: 01534 811O43. Open daily l0am-5pm (4pm November-March). Admission Pounds 3.20; over-l0s and students Pounds 2.l0 (15 per cent discount for groups); under-l0s free. Jersey schools free