8/28 & 8/29

GQ.....
Look at the picture.  It is a cross section from the Grand Canyon.  Can you tell me what the darker stripe is?  Is it older or younger than the other rock?  Why?  

Agenda
Finish Who's on 1st 
Paperium
Radioactive Decay

1.  Apply the rules of relative dating to determine an estimated age of rock strata. 
2.  Investigate isotope decay in order to understand radioactive decay.  

radiometric dating