Having trouble describing

[sandi]

What is a good example to use of a perceptual anomaly and how do you word it properly..??

[sandi]

In particular change blindess I meant...

[ellaa81]

Well there has to be a brief visual disruption so maybe something like...
An observer failing to notice a large change in the set-up of tables at a cafe when a passing tram briefly blocks their view of the cafe ..?
Bit weak but it's something

[ellaa81]

I had a quick look on youtube because I know I watched a few videos of examples of this, not sure if they'll help but here we go
http://www.youtube.com/watch?v=ubNF9QNEQLA
http://www.youtube.com/watch?v=38XO7ac9eSs

[Insomniac]

Change blindness refers to the difficulty observes have in noticing a large change in a visual scene (from the Grivas textbook). An example of this may be the adding in of an object.

[Limista]

You don't have to just stick to change blindness - you can use motion after-effect (reference to Waterfall illusion or spiral after effect) or synaesthesia (sensory cross over).

If you prefer to use change blindness, however, you would give:

the definition: failure to notice large changes in the visual scene 
the reason: change in visual scene should occur during visual disruption (blinking, eye saccades, mudsplash, object moved across viewer's eyes as suggested by ellaa81)