Here are a few experiments which are interesting, flashy, and safe if proper procedures are followed and the amount of reactants is limited.
Reaction of acetylene and chlorine gas.Chemicals needed: Concentrated HCl Solution. Calcium Hypochlorite. Calcium Carbide. Water.
Equipment: Small Erlenmeyer Flask. Two Holed Stopper. Glass Tubing. Separatory Funnel. Graduated Cylinder.
1): Get an erlenmeyer flask and in the bottom put a past of calcium hypochlorite and water. (A thick paste works best).
2): Place a two-holed stopper in the top of the erlenmeyer flask. In one hole put a glass tube bent into the shape of a U. In the other put a separatory funnel, or something else, with a valve that can be opened and shut.
3): Take a large graduated cylinder and fill it with water.
4): Place the opening of the U tube from the Erlenmeyer into the water near the very bottom.
5): Slowly drip concentrated hydrochloric acid into the Ca (OCl)2 flask. Chlorine gas will be generated and after some time will bubble through the graduated cylinder.
6): When you start to see bubbles of gas rising through the graduated cylinder, drop small pieces of calcium carbide (CaC2) into the water. This will generage acetylene gas. When the Cl2 and C2H2 meet, a bright flash occurs. You'll see the flashes and pops all the way up the cylinder as the reactants collide.
Reaction between Aluminum metal and IodineChemicals: Aluminum powder (Doesn't have to be all too fine). Iodine Crystals (Again, they don't have to be super finely ground). Water.
Equipment: Open, flat surface in a WELL ventilated area. Pippette. Flask.
1): Fill a flask with water and place a pippette near it.
2): In the open area, mix together your aluminum powder and iodine crystals. Do NOT use a lot. Only a little bit will give GREAT results and be quite safe. A mixture any bigger than the size of a quarter is asking for trouble.
3): Using the pippette, drip a few drops of water onto the mixture of Al and I2. You will soon see a vigrorous reaction and a cloud of purple smoke. When it's all done, you'll have yourself a big mess and some aluminum iodide.
Making Silicon From SandChemicals: Simple silica, a.k.a. "Sand". Magnesium Powder. 10% HCl Solution.
Equipment: Large Pyrex Test Tube. Bunsen Burner. Tongs. Medium Sized Beaker. Well Ventillated and Cleared Area. Filter Paper. Funnel. Flask.
1): In the large, heat resistant test tube mix your finely divided/ground sand and magnesium powder. (Make sure everything is nice and dry).
2): Using the tongs, hod the test tube inside the fire of the bunsen burner with the opening pointed AWAY from everybody and everything of importance. This reaction is a thermite of sorts, but not nearly as energetic as the one we've all come to know. Still, there may be some unexpected pops and flare ups.
3): Let the reaction go for a while until you stop seeing any noticeable interaction.
4): Allow the test tube to cool so that it can be handled. (It now contains elemental silicon, magnesium oxide, left over magensium, and some magnesium silicide.)
5): Take your HCl solution and put it into a large beaker.
6): Ensure that the contents of your test tube are mobile and able to be dumped out easily. You don't want anything sticking.
7): Once again using the tongs, dump the contents of your test tube into the hydrochloric acid solution. You'll see an immediate flare up and some bright flashes as the reaction occurs. The magnesium silicide is forming silane gas which immediately ignites on exposure to air. The magnesium is reaction with HCl to produce hydrogen gas. All of this ignites as well as any leftover powdered magnesium. The only thing that doesn't react is the elemental silicon which will settle to the bottom of the beaker.
: Decant the still acidic solution off and add water to the silicon left behind.
9): Filter this through the filter paper with PLENTY of water to ensure that all acid has been washed away.
10): Let the silicon dry. You have now made the element silicon from it's ore (sand).