About field lines and continuity of magnetic and electric fields

Question

In my laboratory class we were doing an experiment with grass seeds and iron filings to visualize the electric and magnetic field lines. So, we were discussing why they appear, because we know that the fields are continuous (ie, they don't have holes or empty spaces) and however the field lines appear. We believe that is because of the size of the grass seeds and filings, and if we could use really small particles, we would visualize the "continuity" of the field. Can I have more opinions?

I have read about these fields and authors discuss the math behind the field, but not this kind of situation.

Answer 1

There is something very essential to keep in mind for electric field and that is although the electric field lines are continuous but as you increase your distance from the electric charge which makes the field appear, the strength of the field decrease, and what you have mentioned about the size of seeds is also right, since when the seeds have a small mass they can easily be induced, and get formed in the electric field lines.