Animations tend to be useful to show motion. For example a path animation
can cause an arrow to follow the flow of current around an electric
circuit.
Animations are also useful as you try to build an argument. It is never a
good idea to have too much information on a slide, but sometimes
something builds on itself, and in the end, you need something complex
showing on the screen. If you just show the complex thing to start with,
your audience's eyes will glaze over, but if you show the first step and
slowly reveal the other steps, this can be very effective. This is true
for text and for pictures.
If you can't think of a good reason to use animation for your slide,
don't use it. Animations (and pictures and moving GIFs) that don't serve
a purpose are distracting and detract from your presentation.
--David
--
David M. Marcovitz
Microsoft PowerPoint MVP
Director of Graduate Programs in Educational Technology
Loyola College in Maryland
Author of _Powerful PowerPoint for Educators_
http://www.loyola.edu/education/PowerfulPowerPoint/