Buzzards, vultures, and hawks

Do you know the difference between those three things? 

I thought about this because yesterday, I saw on the news that a "turkey vulture" slammed through someone's windshield on a highway.  They said that turkey vultures are often spotted near highway shoulders circling for roadkill.  They aren't turkeys, but have red turkey-like heads.

I Googled "turkey vulture" today and saw that they can also be called buzzards...and then was led to the fact that sometimes buzzards, vultures, and hawks are used interchangeably.  Not always, but sometimes people use those words to mean the same thing.

Wikipedia says:  "[Hawk is used] more generally (especially in North America) to mean falcons or small to medium-sized members of the Accipitridae – the family which includes the "true hawks" (Accipiters) as well as eagles, kites, harriers and buzzards."

Then it says:  "The Old World vultures found in Africa, Asia, and Europe belong to the family Accipitridae, which also includes eagles, kites, buzzards, and hawks. Old World vultures find carcasses exclusively by sight."

I'm sure scientists could tell you all the distinctions, but I just found that interesting.