History & chemistry of smoking (Science of Cannabis) (UCL)

Uploaded by UCLTV on 10.06.2011

>> One of the interesting things is that people have been smoking
for a very, very long time.
And smoking goes back to long before tobacco actually came
across from North America.
One of the questions is, where does the traditional water pipe
that you see across the Middle East, that one has
in East Asia and so on, which is being used
to volatilise all manner of beautiful natural products -
it's being used for opium, it's being used for cannabis
and of course it's being used for nicotine -
where did that come from?
It turns out that there are all kinds of pipes that you find
in archaeological remains throughout Africa.
And they come, the remains that are found,
come in two essential designs and one is this
which are these bent elbow pipes, and their chronology indicates
that they were pretty well exclusively used for tobacco.
So essentially it's just
like your regular pipe: you put the tobacco in the top
and you light it and then you sort of suck it
through the other side.
The other thing are other much smaller objects
and you can see them there they look like little bowls,
often with a bowl shape underneath,
and for a very long time they seemed to be very, very,
mysterious and people thought that they might be little cups
that people thought they might made small offerings
in or whatever,
until someone spotted that there was actually a hole
that was connecting the top and the bottom and that's
when they began to realise that from sometime
around the 11th century
in Africa people were smoking stuff using these kinds
of devices and looking at modern pipes they realised that that's
where the bong came from.
The bong is actually an African invention
that is the oldest example that has ever been seen
and the idea is simple that what you do is you place lit charcoal
on top of your assembly, you have water underneath -
now let's just see if we can cause an accident
and break this - you lift this out we've got a bit of water,
which I should be able to pour on my laptop,
oh that would be great, it would be so much better if it falls
on my laptop or my phone.
So at this point you can put this on the top
and what you do is you suck the smoke through.
And as you do so you go through the water; what the water does is
several things, one is it cools everything down
and secondly it captures some of the more sort of water soluble,
particularly some of the more acrid, components in the mix.
And the interesting thing is,
the cannabis, the active molecules in cannabis, we've been
mentioning things like THC
so let me just put the picture up here. It's worth looking
at this molecule because there is this long sort
of dangly chain and that
to a chemist looks distinctly oily.
It's the kind of thing which is unlikely to dissolve in water
and you'll notice that most of the rest
of the molecule is actually pretty oily
in character apart from that OH.
So by heating up the stuff here in the charcoal you warm it up
but not to a sufficient temperature,
to actually get it
into the gas phase. You form, in fact, tiny little droplets
which you can then draw through the pipe, but they're not going
to dissolve in the water
and so ultimately they get to your lungs.
Now these are fine, there being lots of modern developments,
here's a small one that I bought in Camden market.
>> And if you want to see any of these demonstrated, by the way,
just this evening when you are finished here just drive
down the Edgeware Road in London
because every second cafe has these contraptions
out on the table for people to use.
>> Well I thought we should build one for ourselves
and I went digging around in the lab
to see what interesting glassware I could find
and I was hoping what we might be able to do was
to get an improved kind of refinement
of the traditional tube, try and extract as much
of that horrible vapour, that acrid stuff as we could.
And so what we have here is a chamber,
and you'll notice that it's got an internal section there
and you'll see the effect in a moment.
So let me just get this on top here.
So we've got plenty of water, then we're going
to put the top tube here and you may be wondering why it's
so long and we'll come to that in a second,
of course we can put our charcoal burner on the front here -
I had a hell of a time this morning desperately trying
to glass blow this bit here, anyway we succeeded.
We could conceivably put our charcoal on there,
it would probably break, but what I'm going
to do now is inhale and I hope you can see
that now we get lots of bubbles.
And so what that means is that we're going to be able
to actually clean up our smoke a lot more
than we would have done otherwise.
And so the basic idea is
that when you smoke this stuff you actually remove some
of the undesirable components
and that's not really a big surprise when you think
about cigarette smoking, most cigarettes in fact come
with a filter on the front
and this is just a kind of variant on that.
But the basic idea is you take the temperature
up just high enough to be able to volatilise it
and not high enough that the whole thing catches fire -
otherwise you lose all those great things -
and they reach your lungs.