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 in a well ventilated area.

1. Collect and dry about a twelve 50cm lengths of the
seaweed and heat them strongly on a tin recipient (container)
until they are ash; probably it will
reduce a quite small quantity, about to a spoonful.

2. Add to the ashes to 20 ml of distilled water
in a beaker, and heat until it boils.

3. Filter the substance (Ash/distilled water).

4. Acidify the filtered with Sulphuric acid solution.

5. Add then the hydrogen peroxide solution,
You will watch the formation of a brown colour because
the iodine liberation from the iodine ions are present.

6. Transfer the mixture to a separating funnel.

7. Extract the Iodine with tetrachloro methane or other
solvent. The result is an organic solution of iodine.

8. 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.

zodiac's method is very good but u can find them on ebay or possibly a chemical supply store. and i can't stress enough how sensitive them are. work with small almounts at a time and handle them very lightly. depending on the how strong the amonia u soak it in is and how good of crystals u have the results will change a lot! u might have a small little almost nothing or u could have a fairly decent bang. just dont do antying stupid with them.♪♪♪

if you want something like the tennis ball then why don't you make the tennis ball and fill it up 1/2 with matches and half with something else like gunpowder, solidox, or C6H7(ONO2)3O?

and the iodine crystals won't do much, it is really sensative and might detonate as you are throwing it. and it will make some smoke that will damage your lungs and stain anything it touches. all it really does is make a loud noise....

take egg whites and soak them in diarreah them wrap it in wax paper and pour bleach on it and then RUN!!!

I hate you.

I would LOVE to see one of you kids try and fill a tennis ball with NI3.NH3

You don't need seaweed to get the crystals, anyway. Just sublimate from a tincture. Duh.

or u could just buy some fucking iodine and let it evaporate into chrystals, any one thought of that?? i mean damn its that simple

u could make an air tight deallyo that u could screw onto a soda bottle and fill with a role or two of mentos screw it on drop the mentos (u would have to have some form of a valve lever that u could open) drop it and run because u will have a sticky mess on ur hands

so, from straight iodine, would you jsut like heat it till it boils, then add like ice to it and let it cool? i heard something like that

im not sure, i was seriously trying to find out if that would work

All you have to do is get an iodine solution and let it evaporate. You can get iodine solution at the pharmacy for disenfecting.