Help me understand interference and diffraction better

[Inertigratus]

Homework Statement

I've been reading a book about waves. I skipped the test earlier this year because I had not done any problems and thought it would be a waste of time to try. But now I kind of have to do it, I've re-read the book but it's much to understand and remember.
Especially the part about diffraction, it's not explained well enough. I'm not sure I even understand how exactly it happens (diffraction). Interference is more obvious, I understand the intuition. But when it comes to actually calculating I get stuck easily.

What I'm asking is if someone has a good resource that explains the phenomena and also how to do calculations. Not too much text would be good as well, already read the book and just need something to help me practically with solving problems.

Thanks!

 

[kuruman]

Go to

http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html

Click balloon "Light and Vision" then balloon "Diffraction." Enjoy.