Slinky; Packham

A magic week for physics! No, not next week’s announcement that the money-pit in Switzerland will now start showing a profit (yeah, right!), nor that its funding would now be directed to cheaper, not to say more useful science… but to the magic slinky!

Drop it and it appears to defy gravity: the bottom doesn’t bother moving until the top comes down to meet it!:

Click for Rhett Allain’s Wired dot Physics posting. It originated elsewhere I think, and I think I got it via Daring Fireball.

It certainly makes people think. Think what a gift this is to physics teachers, but to lots of other types too. I don’t admitting it made me think, and some supposed specialists could do well to bend their minds to this. Maybe James Dyson for example, supposed engineer (but great entrepreneur and general chap), who told the world as part of a BBC British Genius programme, that it was the rear turbine of a jet that provided the thrust, could even learn something here!

The bottom bits of the slinky don’t move immediately because while there is still stretched spring above them there’s still adequate upward force. A slinky is unusual because pressure waves (and unpressure waves and transverse waves for that matter) travel unusually slowly through them. Exactly the same thing happens in other dangled things but waves just travel faster through them.

But it does seem odd to see the deterministic and independent nature of the components demonstrated in this way.

More good science, this time on the TV: Chris Packham as at last got a big nature series all to himself: “Secrets of our Living Planet”. (He may have had one before, but I forgot.) I kept asking myself (I wonder if I was alone): is he a good replacement for David Attenborough? They both have a peaceful sort of appeal, but I think Packham’s emphasis on the scientific is that extra little bit less disguised, which is good, and he emphasises how amazing it all is, particularly in view of the scientific issues. He also seems to get surprisingly close to the animals. I didn’t think you could ‘out approach’ Attenborough! He certainly get’s the ecological web message across though. A gift, of coures, to biology teachers. ‘We’ realise (well, not really me as such since this was one of my mother’s main subjects) it’s not just ‘an interesting aspect’ but it’s the very essence of life. But despite everything relying on it, none of the participants have much if any idea:

“None of the players in the system have any regard for what they’re doing, yet it all works perfectly”.

There’s such an interesting parallel here with the slinky, where all the elements just relate locally, and yet… the centre of gravity of the whole thing will still obey a perfect downwards acceleration of g.

This guy’s gonna get a serious following:

First, with an agouti and the seed of a brazil nut tree (BBC / Adam White), via ironammonite:

From his own website banner:

He did say termites were distant relatives of cockroaches, whereas I think I heard the other day that they’re quite snuggly nested within cockroaches, but whatever 🙂 .

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