Repeat as required

These are some of my samples. They're little bottles of shampoo. Each one contains a different amount of anti-dandruff chemicals in it. (I've been looking at how the anti-dandruff actives penetrate into skin).

However, as you can see, over time the shampoos have settled out a bit. This reveals that the composition is not the same for each of them. This is presumably because the shampoo company that sent me these samples dissolved the anti-dandruff actives in differing volumes of solvent before adding them to the shampoo.

The end result? It might have screwed up my experiment. Or it may have had no effect.

I'm working in the lab to find out!