Is shampoo acidic or basic?
Have you not got indicator paper?
If you have not got any, ask your science or chemistry teacher nicely. They will certainly oblige. Do the experiment with a few drops of the shampoo in water. And report the results back here!
There is an old saying in science:
Just to add, after you do the experiment, i.e. get the results, then you have to do SOME thinking in order to interpret the results. But most scientists would admit that they are simple folk. The challenge is to design an experiment that resolves a scientific question, and leads to a definitive conclusion.