2.1.2 The Lithosphere (KQ1): How Do We Know the Structure?

OK...so we just learned about the Earth's structure...but have you ever seen a 6400 km hole?  So how do we know what the Earth is made of...that there's different layers...and how they impact each other?

The following video explains it very well...puts it in pretty easy terms.  You do need to know the terms p-wave and s-wave.  They are used in earthquake measurements, and we will study them more...but go here for a quick definition of each and a cool animation to go along before viewing the video below.  It will make the video easier to understand.