In article <cc8Kh.2172$2F5.1030@newsfe5-win.ntli.net>,
"Jeremy Watts" <jwatts1970@hotmail.com> writes:
"Dumb_Blonde" <nojunkmale@yahoo.com> wrote in message
news:1173823867.959330.258380@o5g2000hsb.googlegroups.com...
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/firecracker_rocket_project_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.
Well the car engine, or 'Internal Combustion Engine' relies upon using
controlled explosions occurring within a piston. the force of the
explosions obviously pushing against the piston head which in turn is
linked
to your cam shaft which then turns the wheels. In the case of a car the
explosive is an air/petrol (gasoline as you're American) mixture , which
is
then ignited within the piston by a spark plug. The explosions within
all
the pistons (there are several) are all timed so that the cam shaft
turns
smoothly.
What the video clup was showing was this basic idea, that an explosion
within a piston can create linear motion and so drive the piston head
upwards.
the science behind? this can be extremely involved, indeed the
mathematical
description of the burning of gas in automotive engines is a theme of
current
research (for example in order to optimize the shape of the
burning chamber), involving nonlinear partial differential equations
of reaction diffusion type. nothing for a schoolboy. the basic physics
is simple, but as soon as you want to say more than "the bumb introduces a
force
and the force drives the piston " nothing is simple any more.
hth
peter
