Why can you spell sulfur in to ways?

You're right, "sulfur" can be spelled in two ways: "sulfur" and "sulphur". Here's why:

* "Sulfur" is the preferred spelling in the United States and most of the world.

* "Sulphur" is the older, more traditional spelling, still used in some places, particularly the UK and Canada.

Both spellings are correct and refer to the same chemical element. The choice depends on personal preference or regional convention.