The Problem

When this main ingredient arrives from the factory where it is made it comes as large lumps. To make the sun cream, however, this needs to be a powder, like this photograph shows.

Titanium dioxide

QuestionWhy do you think it needs to be a powder? Any ideas? Could you compare mixing different solid materials and see if you can find the difference?

Activity: To try and answer this question, you could do Activity 7

After that, you can see what our scientists think about this problem