In addition to what Nanren said, "Affect" is also commonly used in psychiatric circles to describe mood.

(1) Sarah has given you the normal correct use. (2) It's quite common to see these misused (3) There is another use of each of them that looks different. As Sarah Says "effect" is generally a noun, and it shows the result of change. "Affect" is generally a verb and it means to impact or change. Example of "effect": The effect of the tornado was devastation. Example of "affect": The tornado affected everything in its path. Alternative, less common use "effect a change" "effect" is a verb here, meaning to cause to happen, to cause to come into existence, to implement I can effect a change in the world, if I work hard enough. Even less common "Affect" as a noun meaning outward appearance You are unlikely to come across this except in novels. Probably related to "affectation" which is like a pretense, or guise, or accessory usually designed to mislead or create an impression.

Affect is the action, whereas effect is the end result. For example when i added acid to the base it affected the liquid by making a neutralizing effect. Hope that helps!

Hi Amin, "effect" is generally a noun, and it shows the result of change. "Affect" is generally a verb and it means to impact or change. Example of "effect": The effect of the tornado was devastating. Example of "affect": Gravity affects everything. Hope this helps a little! Sarah