"**THE-RFI-EMI-GUY**" wrote in message
...
I assume the can is open on one end like a soup can, not a coke can. I
think the water is there to provide an airtight, frictionless seal for
more effect. Keeping the firercracker dry is tricky. This looks like a
good use for the hundreds of firecrackers I have left over!

What he is simulating is the explosion that happens in one of your cars
engine cylinders. A car engine operates on a series of small controlled
explosions. In your car, the explosive force drives a piston down,
pushing a connecting rod which in turn rotates a crankshaft. A car
engine has 4 to 8 cylinders which fire sequentially and smoothly. The
links below illustrate this with a single cylinder like a lawnmower
engine. These are "internal combustion engines".

My sister did a similar science project years ago with a coffee can
fitted with a spark plug and filled with a very small amount of gasoline
or ether. A plastic lid was placed on top and an ignition coil made a
spark which blew the plastic lid off. Not as dramatic as a fire cracker.

http://www.keveney.com/otto.html
http://en.wikipedia.org/wiki/Four-stroke_cycle

Dumb_Blonde wrote:

Thank you in advance for your time. I found a neat project to do with
my 14 year old son, but would like to know the science behind it so it
will be educational.

Here is the video link.


http://www.metacafe.com/watch/470767...ct_experiment/

It is a fire cracker experiment, and I know he will love it, but I am
clueless as to how this makes my car run.




--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"©


Their is no explosion in a properly operating internal combustion engine.
The fuel merely heats the air. The expansion of the air pushes the piston.
An explosion called detonation or knock can put a hole in the piston. Some
engines require higher octane fuel to keep knock from occurring.