Slugs and snails and puppy dog tails

doi:10.1136/bmj.332.7556.1519-a

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Trisha Greenhalgh, professor of primary health care

University College London

Fancy making a battery? You will need (a) 10 two-pence pieces; (b) kitchen foil; (c) blotting paper; (d) two pieces of copper wire (taken from any electric wire or flex); (e) malt vinegar; (f) salt; (g) bowl; (h) light emitting diode (available from hardware and model shops); (i) masking tape. Mix vinegar and salt together in the bowl. Soak blotting paper. Stack alternate layers of coin/paper/foil. Attach copper wire to each end of the stack with masking tape. Fix other ends …