Chemical and physical sunscreens essentially refer to the active ingredients used in them. While the chemical sunscreen uses active ingredients that readily absorb the suns rays and are more easily absorbed into the skin, a physical sunscreen contains zinc oxide or titanium dioxide that sit on top of the skin and deflects the suns rays.
Since chemical sunscreens are absorbed into your skin, they are usually not recommended for daily use. Physical sunscreens are better to help you protect your skin effectively and safely.