so Nigel what have we got here we've got
something quickfire syringe and what
does it do well I'll show you what it
does some cotton wadding there okay I'm
just going to compress the air in it and
hopefully it will I don't know what's
gonna do wow that's pretty cool
you made a spark on in was there any
source of fire like a match or anything
down there well as you can see it's
pretty transparent there was no match in
there it was actually just the
compression of the air on top of it
which was able to ignite the the Colin
wall that we had in there you saying if
we compress air we can make it hot
enough to ignite cotton yeah bike
because air is made up of particles so
when you're actually compressing it
you're forcing those particles to
collide closer together which is
actually going to raise the temperature
of in the inside of that tube there okay
can you describe the apparatus form and
what all there is is there's a glass
chamber in there where the cotton wall
sits and as you can see there's this
piston that moves up and down into that
glass chamber and as it moves up and
down you can actually compress the air
so it's like a little plunger look at
like a little plunger yet okay so why
don't we set one up so we can do it
again and do again okay I'll clean the
remnants out what are the tricks here
the trick is to get not too much but not
too little cotton ball and it's good to
get it aerated so that there's a lot of
air around that's what makes it much
easier to ignore just like a good fire
is it just me or do you feel like we're
on a cooking show I feel like we're on a
cooking show
yes who do you think would be Jamie
Oliver in this situation would it be you
or me mmm
I'm Oh mainly sir he's more like Nigella
Lawson let's face it that's a good
planner woods
I wish all right we're ready for this
yes symbols that obviously no matches no
switches no anything okay
um we'll try it again you want me to try
enjoy your drive do you have the
strength we're gonna find out I find out
is it gonna be overweight I think okay
so what I'm gonna try to do is compress
the air in there and by compressing it
I'm going to increase its temperature
because we're pushing all these air
molecules together and if I get it hot
enough to the ignition point of cotton
Oh
the cotton will catch on fire I've heard
that the auto ignition temperature of
cotton is about 400 degrees Celsius so
you can get quite a bit quite enormous
amounts of temperature from a very quick
compression three to one
Oh surprise beginner's luck yeah check
that out so I guess we could generalize
and say if you do the compression quite
slowly then well there's time for the
heat to escape out of the air and so we
don't actually get a high high enough
temperature to cause a cotton to ignite
yeah and there's actually a word for
that it's called a adiabatic compression
that's the one where there's enough heat
generated quickly enough so that we can
get that auto ignition yeah so an
adiabatic compression would be one in
which the heat doesn't escape from the
gas southern half the time - absolutely
all right well let's go see if we can
auto ignite some other things yeah maybe
some here okay
maybe not a good fuel source