I am starting coursework on the effect of temperature on the membrane permeability in beetroot. We have been told to use a colorimeter and a green filter, i was wondering why should it be a green filter?
The best way of setting up a colorimeter is to use ONLY the colour of light that is transmitted by the solution that you are using, because you want to measure light that is ABSORBED, not REFLECTED. beetroot is purple and so reflects red and blue light, but absorbs green. Therefore green light is ther best light to shine through it and a green filter is used.