Robots are Colour Blind!

NASA's Mars exploration rovers Spirit and Opportunity were sent to the planet to investigate its geology. Accurate images of the surface were needed so that possible areas to investigate could be selected and then the rover directed towards them. The cameras onboard the rovers can only record black and white images but colour filters can be used to build up a full colour image. Because the light on Mars has a different colour to that on Earth the cameras need to refer to a known colour standard to calibrate their response, in order to portray the colours accurately.

As well as cameras to take pictures of its surroundings, ESA's failed Beagle 2 mission carried a microscope. This too could only see in black and white but used another set of colour filters to accurately identify the colours of minerals in the rock samples. Knowing the colours of the minerals it is possible to identify them and so determine the conditions that were present when the rocks were formed and the history of their environment since. If the rock samples were formed in warm, wet, shallow seas, as seems possible, then the prospect of life having once evolved on Mars is more likely. Identifying such things which may provide conditions for the evolution of life was the main goal of the Beagle 2 mission .

Students carry out a number of teacher led activities that reveal the nature of colour images, the effects of coloured light on coloured objects and the use of filters.


KS 3

Sci 4.3 f) The effect of colour filters on white light and how coloured objects appear in white light and in other colours of light.


Word Documents

Teacher's Information Sheet

Student's Worksheet


Image Files ( download each file )

Colour Square

Illuminated Colour Squares


Spot Painting

Jelly Bean (Task)

Jelly Bean (Solution)

Coloured Message



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