Here's a good way to demonstrate the effects of astigmatism.
Often used to demonstrate such effects is the stem completion task.
Amongst other uses it demonstrates the effects of geography on economy.
The principle is to demonstrate set effects, as in the film, within a full room using special effects.
Many public tasks demonstrate the effects, both the costs and benefits, of social facilitation.
There were also laboratory studies demonstrating effects on animals and cells that seemed to support the observations.
A study on rats demonstrated potential protective effects against Parkinson's disease.
Kennedy published the first study demonstrating such "parafoveal-on-foveal" effects in 1998.
To demonstrate the adverse effects of poor oral health, take for example the consequences a simple cavity can have on a child.
(Special goggles are used to demonstrate the effects of alcohol).