Everybody knows that you must apply a sunscreen. But not every body understands the basic terms about sun protection. What exactly is a sunscreen made up of? How much sunscreen should be used? What is the basic difference between a sunscreen and a sunblock? What is a physical and a chemical sunscreen? How to choose a sunscreen based on your skin type? What is SPF? What is the minimum SPF value that you should wear? Everything about sunscreen and sunblock that you must know is provided here in this article.