Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: thedoc on 31/03/2016 09:50:02

Title: Why did sheets of glass behave strangely?
Post by: thedoc on 31/03/2016 09:50:02

martyn asked the Naked Scientists:
   Hello, I would like you explain this. I was driving behind this gentleman with a trailer, it had sheets of glass in it but suddenly
the sheets of glass flew out the trailer about 1 every second approx.
My question is why does this go against all known laws of Physics.
But if you watch the forbidden planet could this explain the unknown?
What do you think?

Title: Re: Why did sheets of glass behave strangely?
Post by: Bored chemist on 31/03/2016 20:03:32

I think the wind catching them is more likely to explain it than a TV show.

Title: Re: Why did sheets of glass behave strangely?
Post by: evan_au on 31/03/2016 21:01:42

I think that failing to tie down his load securely may also have had something to do with it.

Title: Re: Why did sheets of glass behave strangely?
Post by: RD on 31/03/2016 23:02:18

Quote from: martyn on 31/03/2016 09:50:02

... I was driving behind this gentleman with a trailer, it had sheets of glass in it but suddenly the sheets of glass flew out the trailer about 1 every second ...

There can be vortex shedding (https://en.wikipedia.org/wiki/Vortex_shedding) behind a vehicle ...

https://youtu.be/tmU-dcK9Q_0?t=6s (https://youtu.be/tmU-dcK9Q_0?t=6s)

which could produce anti-intuitive effects :
 e.g. objects being lifted-up instead of pushed-down by air flow , at regular intervals.

Title: Re: Why did sheets of glass behave strangely?
Post by: Ophiolite on 03/04/2016 16:57:20

Anyone who is so careless in the transportation of glass is no gentleman.

Title: Re: Why did sheets of glass behave strangely?
Post by: alancalverd on 03/04/2016 17:27:24

Aerodynamic lift.

It works for wood and metal aeroplanes, and many small planes are made of glass fibre. Air flowing over the top of a trailer will be at a lower pressure than the air beneath or within it, so the glass will be lifted. As the old saying goes, a piano will fly if you can make it go fast enough.