Homework help - GCSE Science

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I have been asked to help DN with 'Biology' homework. I actually think it is physics. She has been asked to explain the following - I know the explaination but am hhaving trouble 'explaining' it concisely at GCSE level. Please help:

Experiment: 2 test-tubes with boiling water. One wrapped with wet paper & the other with dry paper. Why does the one wrapped with wet paper cool quicker.

Also they give the analogy that you feel colder when your wet.

I think it is the same as sweat - that the water on the surface uses the energy in the tube(body) to heat up & evapourate - but I am struggling to explain why this doesn't apply to the dry paper & how much detail to go into.

Water is a better conductor of heat than air. That's why we use water to cool nuclear reactors. The heat will be absorbed into the water contained in the wet paper. Eventually this will dissapate into the air outside. In the meantime, the dry paper acts as an insulation, effectivly keeping the tube of water hotter for longer.

The holes in the wet paper are filled with water, which will evaporate and take the heat with it.

The dry paper's holes are filled with air, which will act like an insulator and keep the water hot, like a coat does.

Thanks - it is so hard to know how to explain stuff to GCSE students when you have A levels & a degree.

Ahhh, see I only have GCSE's, but science was my A subject.