Testing your mettle
Mike's got a spot of trouble - he's suffering from the corrosive effects of seawater. But he's got a plan, as you can find out in the reef video extra.
The reef diaries
Ellen McCallie's diary about the challenge for the Reef programme, from the BBC/OU series Rough Science 5
Who wrote this challenge? Who builds a burglar alarm for a reef?!?
Turns out this challenge was the brain child of Rob, one of the soundmen. Think of the scale! Our end product will be a 20+ metre floating barrier rigged up with a trip wire powered by waves! I can just imagine us trying to haul this around in the ocean to set it up. I must say, it is a classic Rough Science challenge: big, almost logical, and definitely over the top!
In terms of context, this is a pretty important challenge as well. Reefs are often unintentionally damaged or destroyed by boats when their captains don’t realize shallow reefs are around.
When I said that as my contribution to the challenge I was going get 150 coconuts, people had one of two responses. They either put their order in for their favourite curry with coconut milk or ran for cover, thinking I’d need help grating coconut to make more oil like in the lighthouse programme. (The first steps to getting coconut oil actually give you coconut milk, but that’s not the challenge for this programme.)
In any case, my real challenge was to come up with a very simple solution to getting the burglar alarm to stay afloat. Coconuts in their husk are fabulous for this as they are very buoyant. If you’ve ever husked a coconut, you know how fibrous they are and can see how much air is trapped between the fibres. This makes them much less dense, basically lighter per unit volume, than sea water, so they float.
So I built two rafts for Jonathan’s equipment from wood that almost floats. I then put a net beneath it, trapping about 30 coconuts underneath which push the raft up, so even if Jonathan’s equipment is heavy, the raft won’t sink.
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Content last updated: 26/01/2005








