Is there a difference between sunscreen and sunblock?

Sunscreens are like gel and cream. They are more popular. Chemicals found in sunscreens include PABA, Benzophenones, Cinnamates, and Salicylates.

Sunblock gets UV rays and the sunblock reflects them. Chemicals in sunblocks include Titanium dioxide and zinc oxide.

reference http://beauty.about.com/od/summertanning/f/sunscreenblocks.htm