Leopoldo Twait
Leopoldo Twait voted up Didge Doo's answer

Effect is a noun, as in the Doppler effect, or the Coriolis effect.

Affect is a verb. So, too little sleep can affect your alertness next day.

There's an exception: In psychology "affect" can be used as a noun and relates to the way we display emotion.

And on a comical note, Professor Wolfgang Pauli … Read more