(easy listening music)
- We're here at the Royal Institution.
I'm Dave Porter.
Mike Cuts will be with me later,
and we're celebrating 1 million YouTube subscribers.
We want to set light to a lovely cake
to celebrate all your wonderful subscriptions.
To do that and make it burn really nice,
we're going to need some liquid oxygen.
We don't store liquid oxygen here
at the Royal institution so we gonna need to make it.
What we do have is some liquid nitrogen,
and I've got that in this large dewar here.
I'm just going to decant some into this smaller dewar
and then I'm actually going to pour some
of that into this even smaller dewar.
So, liquid nitrogen boils at minus 196 centigrade.
Okay, you can see it's boiling at the top
of the flask there due to the heat of the dewar,
and the dewar is a double-walled vessel
with a vacuum in between the two walls,
and that means that it can keep
this liquid nitrogen nice and cold.
Why do you need liquid nitrogen at minus one nine six?
Well, because oxygen boils at minus 182.
So, if we pass oxygen from this oxygen cylinder,
through this copper coil,
what we can do is cool it down in the liquid nitrogen,
and that should cool it down
and you can see the oxygen is blowing the vapor away,
but we haven't got any liquid oxygen yet
because we need to cool that oxygen down.
So I'm going to submerse it in the liquid nitrogen
and can see the heat of the copper coil
and even the heat of the oxygen gas is enough to boil
that liquid nitrogen a bit more.
And I can rest that in there now.
We still haven't got anything coming out at the moment.
We will see, just a second,
we get a few drips coming out here.
Oh, here we go.
So we've got a little bit
of liquid oxygen coming out of there
and we can collect that hopefully as we get enough of it
you can see the very lovely pale blue color
of that liquid oxygen
is one of those beautiful things in nature.
Now we're going to need a little bit more than
this to set light to our celebration cake.
This is a nice, clear glass
so we can actually see the oxygen
but it's not as efficient as a dewar or a thermos.
So I'm actually going to replace that clear one
with this thermos,
and we're going to fill this thermos up
and ready for the next part
of our celebration.
Mainly magnesium powder,
and we're going add in two metal salts
just a little bit of barium, chloride and strontium nitrate,
and then they're going to need
to get that all nicely mixed up.
So we've got a nice, fine powder,
leading into a roaring fire.
Mainly white sparks, a few little colored ones as well.
- So we were going to try and count out a million pieces
of this metal dust to represent our million subscribers,
but then we realized that was just going to be impossible.
So what we've done instead
is we have just put quite a lot of it together.
We've guessed, this is about a million.
That's about right.
It's about a million.
- [Dave] Give or take a million.
- [Mike] Yeah, so we we're running with
a quite a big window of error
but you will definitely see sparks
as it rains down on our wonderful celebratory kick.
It should look rather spectacular.
So, shall we try?
- [Mike] I think we should.
Let's get the flame
(roar of fire)
I've got my magnesium powder
and metal salts to scatter down.
To rain down.
- To rain down indeed.
And what I've got here is the liquid oxygen
that Dave made earlier on,
and as I add this to our cake,
when we set fire to it
the liquid oxygen will evaporate
and it will feed that fire much more
than the oxygen in our immediate atmosphere.
So it's going to make it really, really burn brightly.
So I'm going to take the liquid oxygen
and pour it now into our cake.
And hopefully that's soaking up.
I'm going to pour the whole lot in.
Okay, so next thing we do is set fire to it.
(burner turning on)
- And here come the sprinkles.
(roar of fire)
(fireworks popping)
(crackle of flames)
- So there you go.
Our 1 million celebration cake burning in liquid oxygen.
Thank you so much for watching
and watching the YouTube channel over the last 12 years.
- Yeah, so a really big thank you
for helping us reach this massive milestone.
1 million subscribers to our YouTube channel.
So all that remains I think, is to test out
and see whether this cake tastes as good as it looks.
- Maybe not this one.