Where’s the (rocket) science?

27 02 2016

Last week I bemoaned the lack of scientific content in ITV’s new “science-based entertainment” show. Episode 2 wasn’t any better I’m afraid. 

I’m not going to go on and on. We’ll just look at one piece to show the perils of ignoring the science in a science demo. This is a lesson we can all learn from. 

The big set piece this week was a giant-sized version of the bowling ball conservation of momentum demo.   

The idea is simple. In the traditional presentation of this demo an experimenter stands with his back to a wall. He cannot move any further back even if he wanted to. A bowling ball, suspended from the ceiling on a wire, is held against the tip of his nose and allowed to swing away from him. 

The ball swings away then starts to swing back… It’s going very fast… It’s getting closer and closer… Oh, no, he’s going to get squashed… He is trying to squirm back but the wall is in the way… Oh, the humanity!

Then the ball stops (literally) millimetres away from his nose. We all laugh in relief and explore the science. 

I set up and performed this demo for the BBC show Bang Goes the Theory Live when we were in Blackpool performing in the shadow of the Pepsi Max Big One roller coaster at the Pleasure Beach.

I didn’t put up a backboard or do it against a wall each of the TV presenters had to come up on stage hold the ball to their noses and not flinch as the ball came back towards them. I set it up that way because they all understood the science. It was a test of their confidence and courage. 

The science is simple. Drop a ball onto the floor and however bouncy the ball and hard the floor the ball cannot bounce to the same height it was dropped from and it certainly can’t go any higher

This goes the same for a ball that is rolled down the inside wall of a bowl. It cannot reach a higher point on the opposite wall and it certainly won’t reach a higher level than it was let go from when it returns

I used it in Blackpool to show why a roller coaster is towed up to its highest point at the start and then released. Despite all the ups and downs, accelerations and decelerations, and in this case a loop, the car never returns to the same height or goes higher.  

And it’s the same for our bowling ball. As long as the ball isn’t pulled back further than the tip of the experimenter’s nose, it can’t reach a higher point on its return so it can’t smash into the experimenter’s face. Knowing that, however, doesn’t make it any less scary or nerve-wracking for the person in the way or dramatic for us to watch. 

How you explain the science depends on your audience and your aim in doing the demo. One way might be to say energy cannot be created or destroyed. Our balls start with a certain amount of energy. As a bouncy ball bounces or a bowling ball swings friction and air resistance mean some energy is transformed from gravitational potential and kinetic to heat and sound so the balls can’t reach the same height or speed again. You might just say this is why you need to be pushed on a swing

How you explain it doesn’t matter but how you demonstrate it is very important. 

If you don’t show the before, where the object is released from, the after, where it ends up, is meaningless. 

Say you released the bowling ball on the opposite side to the experimenter, so instead of swinging away and then back it just swings towards the experimenter, this is not the same demonstration. This isn’t science this is just trusting someone not to have pulled it back too far or hoping they don’t give it a shove. 

It’s no longer about the experimenter putting their life in the hands of science it’s really just an exercise in measuring how far something is going to swing and putting your target just out of reach. You don’t need to reference the laws of Conservation of Energy you just need a long tape measure.  

And surely no one would do this as you lose all the drama and jeopardy of the before (as the ball is shown right up against the experimenter’s nose, you can actually see it touch his nose, the experimenter can feel it’s cold surface and smell it it’s so close) which makes the after (seeing it stop millimetres from his face) so tense and thrilling. “I don’t need a tape measure,” the experimenter can boldly say before they release the ball, “I trust science!”

And yet that’s exactly what they did on this weeks episode…

In both the small scale “science explanation” with Kevin Fong where they used a bowling ball and in the giant-sized human carrying version they pulled the balls back and just swung them across at the “unlucky” presenter who was apparently “in mortal danger” and “who really, really could die“. Yeah right. 

Instead of spending all that time building false jeopardy it could have been so much more dramatic if they’d respected the whole point of the demo- the science. 

Imagine the presenter in the human-sized ball being winched towards his colleague instead of away. Imagine the drama as they are shown close enough to touch,  close enough to share a last few drama-packed, whispered words “I can’t believe we are doing this! No one has even measured this! This could be fatal” etc before the ball is released. 

The ball swings away then starts to swing back… It’s going very fast… It’s getting closer and closer… Oh, no, he’s going to get squashed… He is trying to squirm back but the wall is in the way… Oh, the humanity!

But no. We saw this. The ball swung across once and stopped well short.   All the dramatic music and pieces to camera couldn’t mask the overwhelming sense of “so what?”.

Last week the science was ditched in favour of drama and hype. This week they went a step further, they ended up ditching the drama and hype because they ignored the science. 

The lesson we can all take away from this is simple: in a well thought out science-based demo the science isn’t something to gloss over, or worse ignore totally, the science is key. The science doesn’t make a demo boring the science makes the demo

Or, in your hunt for drama and entertainment in your science-based show, don’t throw the baby out with the bath water as my old Nan would have said. 




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