Professor Tony Ryan
Just hold on to that for me, just hold on to the end, tightly, yeah.

This is the way we normally experience polymers.
It's bin bags, it's sandwich wrappers, it's all of these things.

A hundred years ago there were no man-made polymers.
Now a balloon's going to go to the edge of space made out of exactly this material and I'd like to introduce you, if you could just drag them in, to the balloonists, Colin Prescott and Andy Elson. [Balloonists enter lecture theatre wearing pressure suits.]

Hello, Colin, hi Andy. [Applause]

So wow, this is some of your balloon.

Andy Elson
This is it, this is the fabric.

Professor Tony Ryan
So how high are you going to go in this balloon?

Colin Prescott
We're aiming to go about twenty five miles above the earth - [wow!] - which is about five times the height of Mount Everest and if we do it, we will break our record, which has stood for over forty years, set by two US astronauts in 1941, highest balloon flight in history and we're going to have a balloon that's about ten times the size of theirs, forty million cubic feet, higher than the Empire State Building [wow] and that will be erm, some balloon, I think you'll ...

Professor Tony Ryan
Aha.
So you're going to go twenty five miles up in a bin bag, right?! [Laughter] Basically, yeah.

And why did you choose polyethylene?

Andy Elson
Well the great thing with polyethylene is where we're going it's going to be, we'll go through about minus seventy degrees centigrade.
Gradually when we get really high, up to about a hundred and twenty thousand feet, it gets a little bit warmer, it's oh about minus thirty, minus twenty.

[Shot of Andy holding polyethylene sheet.] But polyethylene still stretches so the balloon can have some give in it [right, excellent].
We start off with a really tall balloon, with just a little bit of helium.
As the balloon climbs, the helium expands and we need the polyethylene to be able to move and give, otherwise it would tear. [Right].

Professor Tony Ryan
So there are lots of dangers for this balloon fabric, then. Right from the temperature and the pressure ...

Colin Prescott
Well the dangers aren't so much. [Shot showing structure.]
I mean most people think you're going to have bird spikes, you're going to get birds pecking into it and in fact that's not going to happen - or a meteorite's going to fly through it, that's not going to happen either.
But on the other hand if we went through very severe wind ..., I mean this is such an enormous structure, I mean it's about ...

Professor Tony Ryan
Right, this is wind going two directions.

Colin Prescott
Yeah, two directions at different speeds.
I mean it's about nine acres of this polyethylene you've got in the balloon and that could just destroy it and that is a danger.

Professor Tony Ryan
And what protection do you guys need to go twenty-five miles up in the air?

Andy Elson
Well basically we're going to be wearing space suits, like the one over here.

Professor Tony Ryan
Oh, I thought that was one of our audience.

Andy Elson
[Cut to audience/space suit 'sits' between Fritz and boy in audience.] That's actually a suit that we've been using for our training and ... you see, the suit that we wear on the day, we don't want to bring it around and get it kicked about and you know, worn out and that one's been on Mir twice - there's a lot of history with that suit.
And the suit keeps our blood from boiling.
Above sixty-three thousand feet there's not enough pressure to keep a human being alive. And really space starts at about a hundred thousand feet and we're well into space ...

Professor Tony Ryan
[Group stand with polyethylene sheet.] Wow, excellent - so earlier, you all thought that spiders were the better engineers, but what do you think now?

Is it the humans with their fantastic carpets and the bin bag going up to the - [laughter] - or is it the spider? So vote red for spider and green for human.

[Audience hold up score cards.] Yeah, well it looks like we have a bit of a draw on our hands here.
I think that I've shown you that we're getting better than nature and these guys certainly have, so I just want to thank Colin and Andy for coming along and best of luck with the trip and in the last part I'll be asking whether we can learn anything more from nature.
Thank you. Applause