Before I explain the difference between the two; just know as an esthetician, skin lover & sunblock enthusiast, I am ecstatic with your curiosity to know the difference! So lets begin... Sunscreen just like its name only "screens" the harmful UVA & UVB rays from touching your skin. Sunscreen will only partially protect you and is recommended you reapply every 2 hours to provide some type of protection. Sunscreens are usually called "chemical sunscreens" because they contain ingredients that require a chemical reaction from the sunrays to become effective. The active ingredients are absorbed into the body, which then the UV rays are dispersed evenly causing a less harmful energy to the body. Sunscreens are usually in favor because of the cheaper prices and don't cause a white cast onto the skin. Sunblock just like its name it "blocks" the harmful UVA & UVB rays from harming your skin. Sunblock's are usually a thicker consistency and give a white cast. Sunblock's usually contain the ingredient 'Zinc Oxide', which is the best known ingredient to block sun rays. Sunblock is usually called a "physical sunblock" because unlike sunscreens they cause the UV rays to bounce off the skin. Sunblock are usually not sought out for as much as sunscreens but are a better option for the skin.