Communicating with light
Most of the data we generate and receive (whether emails, tweets, videos or mobile calls) are now carried by optical fibres, which use light to transmit vast quantities of information over trans-oceanic distances. The use of hundreds of wavelengths ....
More details | Watch nowThe Fresnel Lens
Early lighthouses used coil and wood fires before moving on to gas and then electricity powered lights. Massive improvements took place by using a lens system around the light. The development of the Fresnel lens brought what we now regard as the....
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Light is reflected off a flexible shiny surface fixed to the end of a plastic tube. When one speaks into the tubes sound vibrations pass down the tube and make the surface vibrate. The reflected light is therefore sent off from the surface in a con....
More details | Watch nowHow X-rays cracked the structure of DNA
An elegantly simple optical diffraction demonstration with an inexpensive laser pointer is used to show the way in which x-rays can reveal the structure of crystals, and in particular, the double helix structure of DNA.
More details | Watch nowCommunication with Space Probes and beyond
The main problems associated with communicating with distant space probes like Voyager 1 are investigated. The role played by diffraction in limiting the amount of power receivable on Earth is discussed. The further problems of reaching a nearby st....
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