- So how hot is that?
- How hot is it? OK, I'll tell you what, right now
- It'll just explode, won't it?
- This goes up to 300.
OK, welcome back to Exhibition
Chemistry!
I'm so delighted to actually be able to
be joined this month by a real human being
after being locked down for a while.
This is Malcolm, say hello Malcom.
Hello, how's it going.
OK and Malcolm has joined us from the
the English department actually,
here at school and we're going to be having a look at some steam,
which is kind of interesting because
Malcolm's just been visiting some
Roman ruins and we were talking about
how close
they were to sort of investigating 
getting steam power to work.
So, before we get into things, 
we'd better pop on some eye protection.
Looking good buddy. 
OK, and we want to first of all just have a little talk
about what we have up in front of us. 
So, Malcolm do you want to just briefly
describe what you can see around you 
and what you think's going on.
So there's a beaker
on a hot plate and a copper tube coming
out of the beaker
and a big glass tube going up much higher
and there's some white stuff in the
beaker.
The white stuff that's in there
those are sort of like
boiling chips they're basically to help
as we begin to heat this up we're going
to start boiling the liquid
and it's going to boil a little bit more
smoothly a little bit like
sticking raisins inside--
have you ever stuck raisins inside fizzy pop
and watched them dancing up and
down? You should try that it's awesome.
OK, so they'll start dancing around in
there just to help that go off smoothly.
Meanwhile, this long tube, we want this to be at least 60 centimetres in height.
The objective here is that
obviously we've got a bung on the top
and this is our safety valve so
if we start to sort of boil a little
bit too rapidly in here, then we've got
water in the tube that will begin to
sort of rise up.
We have a long, long warning to
actually take the the water off
of the hot plate in case there's some
kind of a blockage that's occurring.
Or run.
Or run away, there is that as well I suppose.
And of course you're right we've got
this copper tube. You know, I bent
this into shape by hand.
It's a lot easier to do than you
might think
and this is quite easy to come
to hands with.
I think it's about five millimeters
internal diameter on the inside and
I've got it running through this
bung here, but it's pretty simple
apparatus apart from that.
So inside we're beginning to heat up our
liquid and of course our liquid in this
case is water.
And when you sort of think about
what's taking place inside with the
water at the moment,
what do you visualise happening inside there?
We've got our water molecules, you know,
they're getting hotter.
- Yeah.
-  What are they doing?
- So they're starting to run around more quickly.
- That's exactly right.
- Jump around a lot more.
- OK, and our temperature of our substance is
directly proportional to
how fast they're running around
essentially, or specifically it's
their kinetic energy.
And the kinetic energy of the
particles in there is beginning to increase.
And actually in terms of water, there's a
number of different things that you can
be doing around there.
The water molecules could be sort of
moving up-down, left-right, forwards and
backwards, and that will increase their temperature.
There are a few other things that the
water can do without changing its
temperature such as flipping around,
or vibrating in different ways. 
Specifically, in terms of temperature effects
that's like up-down, left-right, forwards-backwards motion.
Now of course in here we have our
water that's sort of behaving
like a liquid and not only are, you know,
these water molecules are not behaving
independently of one another,
there's actually going to be some
attractive forces between those things
within the liquid and of course
if we begin to heat this up hot
enough, in fact at the surface
probably right now, although we can't see it,
something else is probably also
happening other than water molecules
moving faster. 
What do you think might be happening
at the very top surface,
in terms of our water molecules?
- It may be vaporizing.
- Exactly right. OK, so there's this idea that
we've got some energy available to us to
help the water molecules move faster
or some of that energy could be used to
help them overcome
the forces between the water molecules.
But we've got to be aware that
that energy can't be used necessarily to
do both things at exactly the same time.
Meanwhile, we're starting to get a
little bit of action inside our tube here,
and you'll notice that there's a
few bubbles forming
on our little boiling chips.
They're beginning to sort of
hold up and at this point i think what
we're going to do is just take a brief
pause for a few seconds
to do some magic of film fast-forward
until we get this onto a rolling boil
so we can see what's happening next.
So we'll just hit pause for a second and fast-forward.
OK, so we've sort of come along a few
seconds later and we've started to come to a rolling boil inside
and we can see that there's definitely a droplet of
water forming at the end of that tube. 
And at the beginning, as we saw,
that droplet is going to be
relatively cool but as the temperature
in the copper tubing starts to
increase, that water can get up to
boiling temperature. 
So we've got to be careful about that, we're keeping our
hands well clear of that as it's
happening.
- And we can actually hear now, I don't
know if you can hear 
- Yeah.
There's definitely something coming out the end.
I might even move the microphone over here.
OK, so you say you can see
some steam coming out.
When you visualize steam, what does that 
look like to you?
Like a cloud.
Like a cloud, like you see steam coming out of a kettle,
don't you, and this is this weird thing
is that
commonly, we use that word to
describe steam
but actually that's not steam,
that's like mist.
Because what state is steam, 
is it solid, liquid, gas?
- It's a liquid. 
- Aha, now water we know is is a liquid
and mist are droplets of liquid suspended within a gas,
but steam itself from a
scientific perspective, actually
we're talking about water as a gas.
And water as a gas is completely, essentially, invisible.
So the stuff that you see coming out of a kettle, 
actually it's cloud, it's mist,
it's not necessarily steam but there will be
 steam in and around there.
And we can see there's little bits of
clouds that are coming around here, 
so it'll be interesting to see
what we see on the temperature now.
And there's lots of droplets coming out at the end now.
And that's jumped up quite a lot.
In fact the thermometer is struggling to
to catch up with sort of 82, 83, 89
and presumably 90. You can maybe
get a guess for where we are aiming.
- Yeah.
- 92, 93, 94. Incidentally of course
we're not at sea level,
so this probably is not going to get to 100.
We're at 94.95, it seems to be where it's kind of stabilising.
- OK. 
- No major surprises so far, would you agree?
- Yes.
- Yeah, OK. So let's now do a little investigation.
We've got some, what we think are, droplets of water
essentially coming out from the
end of this tube.
- Big science surprise coming up here.
- You're going to set fire to something!
(Chuckles)
Now, if you were to set fire to something,
I've got some some splints here.
Can you hold those for me? 
And we're gonna--
Just got two of them here just because
we're outdoors, a bit of a breeze
You can sort of hold them downwards
to help them keep burning
and the idea is that you want to shelter that,
we'll light it
and then you're going to just leave the
flame in the end there and
when we light this and you put the flame
into the steam,
what do you think is going to happen to the flame?
The flame will go out.
OK, scientific prediction, give it a try.
OK now be careful with your left hand there.
- Yeah.
- OK that's good yeah, and you can see
it's kind of blowing out, you know,
you can see the steam that
and the smoke that's coming across from it.
- No major surprises so far, would you agree?
- Yeah.
OK, now that's because, of course,
- the hottest temperature that this can be right now is--
- 100 degrees.
100 degrees.
And, as an english teacher,
you know that the temperature that paper, 
for example, has to hit in order to ignite is--
- 415 degrees.
- Fahrenheit, of course.
Which in our common parlance, 
our international standard, is about 230 degrees celsius.
And again, that's obviously significantly higher 
than whatever is coming out from here.
- So, how hot can water get?
- I have no idea.
This is an excellent, excellent answer
because we know that the hottest this
can get right now is 100 degrees celsius
because all the heat energy 
that is being supplied to that water
is coming from here.
Anything that escapes up from here is no
longer being supplied with heat energy.
So anything that is a gas
that's escaping from there
has got no more opportunity to heat up
but water can of course get much higher
than 100 degrees celsius,
if it has already vaporised.
So what we're gonna do is
- give it a second chance for some energy, OK?
- Awesome.
OK so i've lit my blow torch slash bunsen
either of those would be fine for
this purpose and we're bringing this in
here and we're just going to heat up 
the copper tubing.
Now, have you noticed anything happening
differently at the end of the tube
over the last sort of 30 seconds or so?
- does it look--
- It's stopped.
- It seems to have stopped, doesn't it.
- Yeah.
That's that's pretty cool, right?
We've got it hotter but it seems to have stopped
doing the thing that it was doing.
Yeah.
But remember what was the thing that you could see before?
The steam coming out, which was the water vapour.
But could you see the water vapor?
- I could see the mist.
- Aha you can see the mist.
And of course there is no more mist now
because this water now is much hotter 
than a temperature at which it could condense
to form those droplets.
The question is, how hot is it?
OK.
OK, so let's see if we can do our repeat experiment
but have a look at it kind of the other way around.
so this time we've got ourselves, because
we are significantly hotter now,
so what we want to do is be
be pretty careful we don't want to put
our hands anywhere near the end of that tube.
OK and just keeping your hands
well clear, and by the way obviously
if we were doing this actually in a
classroom I'd never
actually get a student to do this, 
but you know
I don't mind killing you actually, if I'm honest Malcolm 
you're a nice you're a good bloke, but--
Let's see, what we're going to do is hold that match
right up to the end of the tube there.
It just went!
OK let's give that another try now 
and now it's sort of it's going to get hotter and hotter
over the next couple of seconds
so we can try that with a piece
of paper as well.
We've got smoke almost immediately
coming off from there.
and we've definitely hit our Fahrenheit 451 as it were
sort of more than 230 degrees but it's
interesting because you'll notice that
the paper itself, although it's sort
of charring here, probably won't catch fire
because you still do have
the other thing that is
required for it to
combust of course is a good supply of--
- Oxygen. 
- Oxygen, and of course there's lots of
vapour that's being pumped out from the
end there and displacing
some oxygen vapour from around.
So let's give it maybe one more try
with the match now it should be really
cooking.
- Woohoo. That's awesome.
- There we go! Pretty cool, huh?
So what we've just done there is essentially we've started a fire--
- With water.
- With water.
Which of course
we normally rely on the fact that
water is something we can use to put
out a fire because of course you put it
on there,
all of that energy that is absorbed
from the fire reducing the temperature
down to 100 degrees celsius again,
but in this case we've got
a secondary source of heating
that can actually get the water to
ignite a fire.
Thank you very much Malcom for joining
us, I think we've got to finish with a Wuhan shake,
given the times we're living in.
So, really simple experiment and there's
lots of really cool things that you can
kind of play around with this and some
interesting discussions, so
give it a try and maybe let us know how
you're getting on
and see you next month.
- Thank you very much Malcolm for joining. 
- Thanks Declan.
Bye!
