Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: thedoc on 11/09/2013 14:05:55

Title: How is a London skyscraper melting cars?
Post by: thedoc on 11/09/2013 14:05:55

The 'Walkie Talkie' in London has been damaging cars this week by acting as a parabolic reflector, targeting the sun's rays on passers by...

Read the whole story on our  website by clicking here (http://www.thenakedscientists.com/HTML/news/news/1000306/)

  

Title: Re: How is a London skyscraper melting cars?
Post by: CliffordK on 11/09/2013 11:57:45

Also see discussion here. (http://www.thenakedscientists.com/forum/index.php?topic=48787.0)

Yes, the Walkie Talkie building is an "imperfect" parabolic reflector creating a rather large hot spot, and of course using mostly transparent window glass rather than mirrors as the reflective surface.  But it does reach several times the intensity of the normal sunlight over a fairly diffuse area.

The hot spot is predicted to reach street level only for a few weeks a year, but I've seen little discussion of the effects as it rises into neighboring buildings.

Title: Re: How is a London skyscraper melting cars?
Post by: RD on 11/09/2013 15:11:17

Quote from: thenakedscientists.com/HTML/news/news/1000306/

1. A parabolic reflector is a curved, mirrored surface which can be used to collect and focus energy in the electromagnetic spectrum

http://www.thenakedscientists.com/HTML/news/news/1000306/

They work with sound too : parabolic microphone ...

(https://farm2.staticflickr.com/1076/4597831983_bcfc086d84_o.jpg)


(https://upload.wikimedia.org/wikipedia/commons/c/cf/Denge_acoustic_mirrors_-March2005.jpg)
https://en.wikipedia.org/wiki/Acoustic_mirror