When you say you point lasers at colourful liquids what does that mean and why do you do it ?

Question: When you say you point lasers at colourful liquids what does that mean and why do you do it ?
- Keywords:
  colour,
  experiment,
  laser,
  liquid,
  work
Asked by anon-209475 to Sergio on 11 Mar 2019.
- Sergio Adan Bermudez answered on 11 Mar 2019:
  
  That is a great question! In my research, I work with drugs that are used against cancer. These drugs need to absorb the light to work, and because of that, they have specific colours. I am lucky enough to work with chemicals that are very colourful, even some of them were discovered to use to dye clothes.
  
  The way that I make the drugs work is by using a laser, similar to laser pointers that you can play with, but more powerful. And that is basically my daily work ^^

Question: When you say you point lasers at colourful liquids what does that mean and why do you do it ?