Refraction vs Diffraction

[joshhunte]

Currently reading Todd Lammle's CCNA Wireless book.

It's a pleasant read however I have noticed a few errors - most I think have been covered by the errata on the Sybex publisher site.

However I'm slightly stuck on Page 50 of the book whilst explaining RF behaviour:

"Diffraction is commonly confused with refraction, but the two are vastly dissimilar because diffraction bends the RF, whereas in refraction the RF bounces."

If I go to the Refraction section on the previous page it describes how drier air bends the signal away from the earth and how humid air the opposite. Likewise Diffraction is described as the signal bending around objects.

Please can someone provide a clearer explanation.

Thanks.