Pure CS is not necessarily equivalent to pure maths. For the “science” bit of CS, you do need to do the equivalent of experiments (for more applied topics).

For example, a physics degree is expected to have experiments. You are not required, expected (and possibly do not want) to know the tools required to professionally build a bridge because you did courses on mechanics. But you might do an experiment on the structural integrity and properties of small structures.

Whether this is a good split is an entirely different question.