Apologia Physical Science, Module 6, asthenosphere.

It took long enough but I finally finished this blog post all the way back from Module 6.  Oh well, like any full-time, single, working, homeschooling mom, I am busy.

So here is what we learned about the lower part of earth's mantle, the asthenosphere.http://en.wikipedia.org/wiki/Asthenosphere.

~The asthenosphere is between 300-500 degrees Celsius.  That is over 550 degrees Fahrenheit and just under 1000 degrees Fahrenheit.  Ouch!

~The asthenosphere is just under the lithosphere and is between 60-150 miles beneath earth's surface.

~The asthenosphere is approximately 90 miles thick.

~This is a solid layer of rock but there is so much pressure and heat, the rock can flow like a liquid.

~The asthenosphere enables plate tectonics to move.  We are going to dive into the plate tectonics today so more about that later.

Check out this cool experiment.  My kids have been playing with the ooeey gooeey cornstarch and water mixture since they were little so they are familiar with the concept of a Non-Newtonian fluid that can be liquid or solid depending on the pressure placed upon it.  In the mantle, the inner asthenosphere a.k.a. plastic flowing rock behaves this same way.

So just grab a pan, a cup of cornstarch, two-thirds cup of water, and a spoon.  Put the cornstarch in the pan and then start to add the water.  Mix it, a little hard at first but keep going.  (hands work much better IMO).

All mixed up and in the pan.  It looks smooth and shiny,
it looks like cake batter but boo, it is not!  Looks can be
 deceiving here too. The mixture looks as though it would
be soft and malleable but guess what, it is not.  When you try to
pick up the mixture from the pan by hand or spoon, it is rock hard.

But when you do pick it up and hold it in your hands, it quickly turns into
a silky liquid mixture that you can no longer hold.  

This is a really fun and easy way to understand
what is going on in at least the asthenosphere of the
earth's mantle.

When it is time to clean up, DO NOT WASH THE PAN OUT IN YOUR KITCHEN SINK UNTIL ALL OF THE CORNSTARCH AND WATER ARE DUMPED OUT, OTHERWISE, YOU WILL HAVE A GREAT CLOG ON YOUR HANDS.

Find out more here at Buzzle.