what do you mean with ” things that change colour or glow”?

Question: what do you mean with " things that change colour or glow"?
- Keywords:
  colour,
  glow
Asked by Marc_Casases to Carmen on 11 Mar 2015. This question was also asked by Iain.
- Carmen Denman answered on 11 Mar 2015:
  
  Hello,
  
  I mean this: Some bacteria I work with I have engineered to express a protein called ‘green fluroescent protein’. These bacteria glow when excited with a certain wavelength of fluorescent light on a microscope. Check this link out:
  https://www.google.co.uk/search?q=gfp+bacteria&espv=2&biw=1280&bih=899&tbm=isch&tbo=u&source=univ&sa=X&ei=hUIAVYyqF8eX7Qbl8YGgCw&ved=0CC4QsAQ
  
  There are also some experiments, like the Bradford assay or the Dubois assay, that change colors due to oxidation of sugars, or activation of or interaction of chemical components used in the experiment. Color changes like this: https://www.youtube.com/watch?v=NABYn4wY84c
  
  Cheers!
  
  Carmen

Question: what do you mean with " things that change colour or glow"?