St. George's School Duisburg Food, Glorious Food!

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Middle School & Upper School
Infrared Imaging
Visible light ranges in wavelength from 390 - 750 nm, where 1 nm is one thousandmillionth
of a metre. Human eyes cannot
directly observe signals sent with light
outside of this wavelength range. For
example, it is not possible to see the infrared
(IR) beam that a typical TV remote controller
emits.
Year 12 AS Physics students have been
investigating how to capture an image of
infra-red light and use this to determine its
wavelength. As shown in the picture, they
found that the charge couple device chip in a
normal digital camera produces a response when illuminated by IR light.
With the aim of determining the wavelength of IR light the students set up the apparatus
shown below. The laser beam is passed through a a thin film with parallel grooves
etched onto the surface every six hundredth of a millimetre.
As the laser beam passes through the film, the light
spreads out from each groove and then interferes
to produce a series of bright and dark spots on a
white screen 2.5m away.
Using a digital camera the students carefully
recorded and then analysed an image of the interference pattern. The students found the
wavelength of IR light to be 940 nm, just as it said in the textbook.
IB Corner
Mr A. Ebbens
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With the current world economic situation, IB economics students are starting to look
at how governments can use different policies in order to stimulate world economic
growth, reduce inflation and unemployment while at the same time being aware of
ethical and environmental issues. These are complex issues that have proven
challenging for the governments of the world, let’s hope the next generation of St
George’s economists can come up with the answers to these important issues.