Schlieren Optics – See small changes in the index of refraction in air
1–10 of 32 posts
Re: Schlieren Optics – See small changes in the index of refraction in air
#2Invented 1864!
http://en.wikipedia.org/wiki/Schlieren_photography
And there's a variant in color: https://www.youtube.com/watch?v=0g4UBeaG5fs
Re: Schlieren Optics – See small changes in the index of refraction in air
#3The HN title is incorrect. This device doesn't show movement, it shows difference of the index of refraction. From the video description:
> Demonstration of an optical technique that allows us to see small changes in the index of refraction in air. [...] Seen here are the heated gases from a candle flame and a hair dryer, helium gas, and sulfur hexafluoride gas.
Re: Schlieren Optics – See small changes in the index of refraction in air
#4The HN title is incorrect. This device doesn't show movement, it shows difference of the index of refraction. From the video description: > Demonstration of an optical technique that allows us to see small changes in the index of refraction in air. [...] Seen here are the heated gases from a candle flame and a hair dryer, helium gas, and sulfur hexafluoride gas.
Technically true. But the different refraction indices can be created by turbulent flow - which will nearly always occur with moving air.
Re: Schlieren Optics – See small changes in the index of refraction in air
#5What are those circle shapes?
Re: Schlieren Optics – See small changes in the index of refraction in air
#6This is basically the same effect you see with shimmering above a hot road surface.
Re: Schlieren Optics – See small changes in the index of refraction in air
#7Invented 1864! http://en.wikipedia.org/wiki/Schlieren_photography And there's a variant in color: https://www.youtube.com/watch?v=0g4UBeaG5fs
There was a yellow version shown on Time Warp.
Re: Schlieren Optics – See small changes in the index of refraction in air
#8And it's kindof accessible for hobbyists, here is the website of one individual who made his own setup: http://www.ian.org/Schlieren/
The most expensive component (except the camera) is the mirror. According to that website, it costs about $100 from an optics company.
Re: Schlieren Optics – See small changes in the index of refraction in air
#9What are those circle shapes?
I think they are aberrations in the mirror's glass. People used to use Schlieren optics-esque techniques to test glass for defects.
Re: Schlieren Optics – See small changes in the index of refraction in air
#10The NPR has a good explanation of how it works in their video: