RICHARD AMBROSE: You know you can do some amazing things with rubber Jonny.
JONNY PHILLIPS: I know. Look at this ball I've made just using rubber bands, isn't it good.
RICHARD AMBROSE: Mate I was thinking of something a lot more exciting than that.
JONNY PHILLIPS: Like what?
RICHARD AMBROSE: Like this...
SOUND ON TAPE: Aghhhhhhh!
NARRATOR: Bungee jumping....and this is how they test the rubber ropes
NARRATOR: These elasticated bungee ropes are the only thing between you and certain death, so they're tested daily.
NARRATOR: Bungee jumping was inspired by the people of Vanuatu in the South Sea Islands, who, in a centuries old ritual, use vines to jump with death defying precision from wooden platforms.
NARRATOR: If you jump here though, you'll be pleased to know that these ropes are military shock cord. The same cord is used in missile launch tests.
NARRATOR: Inside, the cord is made from 380 strands of Malaysian rubber, with a cotton outer core and a polyester cover.
NARRATOR: The crew will check each rope manually every single day and the ropes are de-commissioned after around a 1000 bounces.
NARRATOR: Once the cord is all hooked up, it's time for a test bounce.
NARRATOR: The test uses ordinary gym weights tied in a bag - 135 kilogram's of them - exceeding the heaviest jumper's weight for extra safety.
NARRATOR: They go up to the jumping height of 55 meters.
NARRATOR: The rope can stretch up to 3.3 times its length, so even at full stretch you would bounce seven meters above the ground. A bungee jumper wouldn't stretch it to the max though so the clearance would be even bigger. The weights shows that everything is in order.
NARRATOR: And now for the final test.....with a human subject.
TESTER: Here we go.
NARRATOR: Some jumpers won't jump until they've seen the pros do it first.
NARRATOR: Bungy expert George has done over 200 jumps, but even he still gets the willies.
TESTER: 3,2,1, Bungy!
NARRATOR: As the rope kicks in, George is travelling at over 70 kilometres per hour.