ok generally i do not do anything from totse.com but this method does work it is basically the same as what bud said
Ok, lets see an easy experiment supposing you want to prepare the Iodine first. You will need:
Bunsen burner and asbestos square (or a hot plate)
Tripod and tin lid
Beaker, 250 ml
Separating funnel 100ml
Evaporating dish
Hydrogen peroxide 20 volume
Tetrachloromethane or dichloromethane
Distilled water
1M solution of Sulphuric acid
Supply of ribbon seaweed(Laminaria) - that you can obtain a a biological supply store or from the sea shore
Procedure
(You must work at a fume cupboard)
Collect and dry about a dozen 50cm lenghts of the seaweed and heat them strongly on a tin recipient until they are reduced to ash; probably it will reduce a quite small quantity, about a spoonful.
Add to the ash 20 ml of distilled water in a beaker, and heat the suspension until it boils.
Filter the suspension
Acidify the filtered with Sulphuric acid solution
Add then the hydrogen peroxide solution. You will observe the formation of a brown colour due the iodine liberation from the iodine ions present.
Transfer the mixture to a separating funnel
Extract the Iodine with tetrachloro methane or other solvent. The result is an organic solution of iodine.
In order to obtain crystals , the solvent may be allowed to evaporate at room temperature, by placing it in an evaporating dish in a fume cupboard. It will result crystals of iodine or rather gray-black brilliant flakes.