ok, so some quick things you need to know:
-this will throw small and large bits of rock over a very large area, do not do this inside or you will either ruin your house or kill someone.
-this isnt that loud, so dont expect to use this to wake up the neighbors
start out with:
a rock that has been soaked in water for a while, i.e. pulled out of a river that is not dry
a freezer not really required, but makes the blast radius 30+ meters and kill radius 3-5 more meters
a heating element its best to use a fire, like a pile of wood soaked in gas and then light it on fire and let it burn for a while so there are lots of coals and its really hot. you can use a over or mircowave, but it will totally ruin the oven, ive done it in a old mircowave and it was quite epic, but i now need a new microwave :facepalm:
step uno (1): get rock, if it wasnt pulled from a river, let it soak (totally covered with water) for a least a week. this allows the water to get inside the rock.
note: you can then put the rock in the freezer after it has been soaked, this makes the water particles shrink.
step qui (2): make fire, or start up heating element. if its a fire, let it burn for a long time, add plenty of wood and get lots of coals. if its a over or whatever, start it up and crank it to high and let it run for 10 min. this should make it very hot. if its not hot enough to burn your skin if you put your finger inside, crank it up and let it run for even longer.
note: i have done this in a microwave, i turned it to high and let it run for 15 minuates, then i put some coals from a fire on the glass plate inside the microwave for even more heat
step tri (3): take rock out of bucket and put into the heat element, you dont have to quickly take the rock out, becasue the water will not rush out of the rock, however do not have the rock out of water for more then 3min
step 4: wait for it (run, run!!)
step 5: wait for it (dives behind trash can)
step 6: ssssssss boooommmmm
what just happened: the water inside the rock expanded at such a high rate, the rock split apart in an awsome pattern =) this is much like the idealogy behind military grade RBX (quick expansion of matter = particle sepration = boom)