This challenge is probably easiest if you are a teacher of the sciences or mathematics.
Check out the collection of Animated GIFs at http://educationalgifs.com/archive You may also search elsewhere. One technique that might work is to use the term animated gif in a Google Image search. An example for “nutrición diabetes”.
Select a GIF. In the response to this challenge, paste the web address of the GIF into the appropriate field, and in the description describe why you chose the GIF, and what sort of lesson you might use it for.
Example for "Find an Animated GIF you could use in a lesson":