works bombs are fun. i do them with 20 oz bottles so you can make more for less $$. they really aren't that dangerous...the boom just comes from the pressure building up in the bottle...realistically you could accomplish the same thing with vineager and baking soda, dry ice, etc.
and I'm calling shenanigans on whoever said they blow craters in their yard...you would have to make it in a 55 gallon drum to do that shit.
That would probably work, but the Works is cheaper.
Hint: Use Gadoraid bottles, the thicker plastic allows for more pressure.
throw it in a big puddle or a swamp, it make a huge splash
and yah, NEVER touch the shit after it explodes, if the shit is stong enough to burn through tin foil then think of what it could do to your skin.