Electromagnetic Spectrum

    The Nipplewort flower in visible light. Image by: Bjørn Rørslett/NN. Nikon D1H , UV-Nikkor 105 mm f/4.5 @800 ISO

    The Electromagnetic spectrum (EM spectrum) is how scientists describe the range of different frequencies of energy released and absorbed by objects – most familiar to us as the visible light we can see and the infrared heat we can feel from the Sun. The scale starts off with long, low waves known as radio waves and as we move up the scale the wave lengths decrease until we get to the shortest wave lengths which are known as gamma rays.

    There is a lot more to the world we live in than what you and I can see. Human eyes can only process EM waves within the ‘visible light’ range. However, not all animals can process the same part of the EM spectrum: bees are able to see some of the UV wave length.

    For the parts of the EM spectrum that we can’t see, we have to design and use technology that can. Each wavelength is more suited to looking at particular scales of objects; long radio waves are suitable for probing deep into space at far off planets and black holes and x-rays in massive synchrotrons are used to diagnose subtle engine faults in F1 engines.

    The Nipplewort flower in UV light. The parts of the flower that are essential for pollination ‘fluoresce’ under UV, guiding the bee in. Image by: Bjørn Rørslett/NN. Nikon D1H , UV-Nikkor 105 mm f/4.5 @800 ISO

    Some scientific areas such as astronomy or materials science rely on using multiple wave lengths to reveal details about an object. Each image is laid on top of another to pick out different details such as what it is made of and hot and cold spots. All this information can give a more ‘complete’ picture and improve our understanding.

    As scientists continue to develop new techniques, technology and reasons why we should continue the exploration and application of the EM spectrum increasing our understanding of how to best use each frequency and the data we get from this, science can apply each part of the EM spectrum to improving applications such as security, medicine and space which will affect our everyday lives.

    Typically the spectrum is divided into 7 wave lengths:

    1. Radio waves – that your radio uses

    2. Microwaves – used by your phone

    3. Infrared – used by police thermal imaging cameras

    4. Visible Light – used by your eyes to see

    5. Ultraviolet (UV) – used to read barcodes

    6. X-rays – X-ray body scans

    7. Gamma rays – used for radio therapy cancer treatments

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