Sunscreen

• According to Lifespan, sunscreen features materials that act as a filter of sorts, thereby allowing some UV light to get absorbed into the skin, while blacking out some of the sun's UV rays as well. Keep in mind, however, that sunscreen blocks only some of the sun's UV rays, not all of them, meaning it's not a 100 percent preventative in terms of skin cancer.
  
  

Sunblock

• Sunblock, meanwhile, features metallic materials that reflect and scatter the sun's UV light rays. Sunblock essentially serves as a wall between your skin and harmful sun UV rays, making it much more adept at preventing skin cancer than sunscreen.
  
  

Ideal Use

• Sunblock is best used on those with very sensitive skin, as it features titanium dioxide and zinc oxide, which are far less irritating to the skin than the Parsol 1789 put in sunscreen. Sunscreen, meanwhile, is ideal for protecting the skin against sunburns. It is also easier to find in stores than sunblock, making it a nice outdoor product for those who do not have extremely sensitive skin.
  
  

Blending Sunblock and Sunscreen

• As it turns out, most sun-related lotions on the market today feature a combination of sunblock and sunscreen, so those desiring a pure sunblock should carefully read the ingredients, or consult an employee at the store from which you're purchasing. Also, keep in mind that sunblock and sunscreen are both good at protecting the skin, particularly compared to no lotion at all, so wearing either during all outside use is acceptable.
  
  

SPF

• SPF (Sun Protection Factor) lets you know how much your lotion is protecting you from the sun. For instance, if you normally begin to turn red after 15 minutes in the sun, an SPF 15 offers 15 times more protection than does your natural skin. It's best to purchase a sunblock/sunscreen with an SPF between 15 and 60. Anything lower than 15 will not provide enough protection, while anything higher than 60 really doesn't do much more for you in terms of shielding your skin from the sun.