Chapter  1:  Plate  Tectonics  Section  1:  Earth’s  Interior  

Exploring  Inside  the  Earth  

*  Geologists  have  used  two  main  types  of  evidence  to  learn  about  Earth’s  interior:  *  Direct  Evidence  –  rock  

samples  *  Indirect  Evidence  –  

seismic  waves  

Important  Factors  When  Traveling  to  the  Center  of  the  Earth  

*  Temperature  *  The  deeper  you  travel  

the  higher  the  temperature  becomes.  

*  Pressure  *  The  deeper  you  travel  

the  greater  the  pressure  becomes.  

Layers  of  the  Earth’s  Interior  

*  The  3  main  layers  of  the  Earth  are  the  Crust,  the  Mantle  and  the  core.  

*  These  layers  vary  greatly  in  size,  composition,  temperature  and  pressure.  

The  Earth’s  Crust  

*  The  crust  can  be  looked  at  as  the  Earth’s  skin.  *  The  crust  includes  dry  land  and  the  ocean  floor.  *  Oceanic  Crust  –  water  *  Ex.  Basalt  *  Continental  Crust  –  land  *  Ex.  Granite  

The  Earth’s  Mantle  

*  Earth’s  Mantle  is  made  up  of  rock  that  is  very  hot,  but  solid.  *  Scientists  divide  the  mantle  into  layers  based  on  the  physical  characteristics  of  the  layers:  *  Lithosphere  *  Asthenosphere  *  Lower  Mantle  

The  Earth’s  Core  

*  The  core  is  mostly  made  of  the  metal’s  iron  and  nickel.  It  consists  of  two  parts:  *  Outer  Core  *  Layer  of  molten  metal  that  surrounds  the  inner  core  *  Behaves  like  a  liquid  

*  Inner  Core  *  Dense  ball  of  solid  metal  *  Extreme  pressure  squeezes  the  atoms  of  iron  and  nickel  so  much  that  they  cannot  spread  out  and  become  liquid  

The  Core  &  Earth’s  Magnetic  Field  

* Scientists  think  that  movements  in  the  liquid  outer  core  are  what  cause  Earth’s  magnetic  field.  

Chapter  1:  Plate  Tectonics  Section  2:  Convection  and  the  Mantle  

Types  of  Heat  Transfer  

* Radiation:  * The  transfer  of  heat  through  space.  * There  is  NO  direct  contact  between  a  heat  source  and  an  object.  * Ex.  Sunlight  

Types  of  Heat  Transfer  

* Conduction:  *  The  transfer  of  heat  within  a  material  or  between  materials  through  touching.  *  Ex.  A  Spoon  is  heated  up  through  conduction  by  the  touching  of  the  hot  liquid  in  the  pot.  

Types  of  Heat  Transfer  

* Convection:  *  The  transfer  of  heat  by  movement  of  currents.  *  Caused  by  differences  in  temperature  and  density.  * Density  –  a  measure  of  how  much  mass  there  is  in  a  volume  of  a  substance.  

Convection  Currents  

*  Heating  and  cooling  of  a  fluid,  changes  in  the  fluid’s  density  and  the  force  of  gravity  all  combine  to  set  convection  currents  in  motion.  *  Convection  currents  

continue  as  long  as  there  is  heat.  *  Heat  from  the  core  and  the  

mantle  itself  cause  convection  currents  to  happen  within  the  Earth’s  interior.