The first dive of the season for some club members involved a visit to the London Diving Chamber at the Hospital of St John and St Elizabeth near Lord's cricket ground. Dressed in fetching scrubs, 8 divers plus a member of staff did an evening chamber dive to a "depth" of 40 metres. Bottom time was 12 minutes, and divers were in the chamber for 45 minutes in total.
A clear briefing was given before the dive, with the relevant physics explained as the dive progressed. Nitrogen narcosis was felt, and the effects of this on divers was illustrated by a test (involving circling letter "L"s on a piece of paper) before and during the dive. Sally somehow managed to score better when under the influence of nitrogen. Experiments with paper cups were also carried out (they fell to the floor slower in the denser air). The temperature in the chamber rose significantly as the pressure increased. And everyone had squeaky voices, an effect we don't notice on actual dives as we can't talk underwater.
There is already talk of a return visit. A minimum of 6 people would be needed. The cost is £30 per diver.