I've just sent the better of my hot plates to Japan.
None of this stuff is quite straight.
This is my apparatus for, which we're going to use to
light a match with water.
Sounds an improbable thing to do, but that's what's going to
happen hopefully.
I have never actually done this before, so maybe it won't
happen, but we'll see.
So we're going to boil water in here, over a Bunsen.
The steam is going to boil off, flow through these tubes,
into the coil, and out here.
And while it's flowing around the coil, we're going to try
and superheat it with a blowtorch.
So when it comes out, it's a few hundred degrees
centigrade.
And hopefully that will be enough to light a match.
Of course it would have been helpful if I'd filled that
from the hot tap.
Oop.
Classic schoolboy error.
OK.
That will take a couple minutes to come
to the boil, I think.
You can't normally light a match with
water, or even steam.
Because it's just not hot enough.
The normal steam you get off boiling water will condense
pretty much immediately on anything because it's only
just above its boiling point.
So as soon as it hits anything cooler, it will just condense.
It's getting hotter quickly, actually.
We want to really heat the steam up to
a few hundred degrees.
At which point, hopefully we'll exceed the autoignition
temperature of the head of the match.
So the head will have a temperature at which, if you
raise it to that temperature, it will spontaneously ignite.
And that's what we're trying to do.
Just to heat this water hot enough that that will happen.
OK.
So the thermometer is reading quite a lot
less than 100 degrees.
But that's probably not really a surprise.
We've got this huge coil, which at the moment is acting
like a condenser.
So we're probably not getting water above 100
degrees out the end.
Which is where the blowtorch comes in.
So you saw just now, before I started using the blowtorch,
there was a lot of condensed water dripping out
the end of the pipe.
The plume of droplets, the plume of water mist that you
saw coming out as the water condensed, is now pretty much
disappeared completely.
Because it's now too hot, and it's not condensing when it
comes out at the end of the pipe.
It's a bit of a problem juggling all these extremely
hot objects.
But - I'll probably just take the blowtorch
away while I do this.
Oh.
Not bad.
I've never seen a match do that before.
It sort of smoldered without igniting.
Didn't know that was possible.
I wasn't convinced that there was enough
heating going on there.
So I've got another Bunsen out.
We'll see how we get on with that.
So I've set the water boiling off again.
Let's light this other Bunsen.
Now we've got our copper coil actually glowing red hot.
So I think this is going to do the job now.
I don't think it is that easy to melt copper.
I think it'll radiate a lot of heat before it
gets to that point.
OK.
So let's give the thermometer a go.
See if we're - see how hot we might be.
It's really racing up.
Nope.
Hm.
I see.
Well, I've learned something new today.
I've learnt that my thermometer only goes up to
200 degrees.
So we've maxed it out.
Oh.
There we go.
That's a really interesting observation, actually.
And I think that the problem we had before was not so much
that it wasn't hot enough, but that I was just holding the
match too directly in the stream of steam.
And not pulling out as it started to smolder.
And obviously, there is no oxygen in what's
coming out of here.
This is pure gaseous water.
So there's no oxygen there.
So the match wasn't actually able to ignite.
And I think that was probably the problem.
And now: A, we've increased the heat.
But B, if I just stick it into the stream and then withdraw
it, to allow the air to get to it, at that
point the match ignites.