Lecture Oct 10. Jennifer Blazejack

Introduction
Geologically Active
Earth's Surface
The Greenhouse Effect/Cooling Rates
Earth as a Living Planet
Conclusion 
Introduction
We were handed back previous quizzes and told that if we were not positive of the answers to reread the sections or ask our teacher directly to get help for the correct answers. We were told that the exam is multiple choice and that the Chapters 1-7 would be on the exam. Afterwards, a slide show on Super Earths was shown while other students completed the quiz. 
Geologically Active
The Earth has 3 layers: The core, mantle, and crust (which includes the lithosphere).  The core has the highest density, the mantle has a lower density, and the crust has the lowest density. Differentiation results in layers made of different materials. An example of differentiation is an oil and water test. Oil rises to sit on top of the water because water is denser and you can visible see the different layers. Convection is when hot materials expands and rises while cooler material contracts and falls. An example of convection is Earth's mantle- it would take 100 million years for a piece of rock to reach the top of the crust from the mantle's base. 
So can a rock stretch? Yes, if done correctly. As long as there is enough heat and the rock is slowly pulled at then the rock can stretch. But if there is not enough heat and the rock is pulled quickly then the rock breaks into pieces. 
Seismic waves happen in the Earth. An example is a Slinky. When the Slinky is held and pulled left to right then the wave goes those directions, called a P wave. When a slinky is held and moved up and down then the wave goes perpendicular to the direction of travel, called an S waves. S waves explain why an Earthquake can be felt only on one area on one side of the world and not the other side- S waves are stopped by the Earth's liquid core.
Auroras are pretty to look at, but be careful! They contain solar radiation and the further up you go in the North Pole the more radiation you are exposed to. 
Earth's Surface
Asteroids can be compared to dropping milk. The asteroid is hot and liquidy when it hits the surface and rock "splashes" everywhere, like when milk hits the floor and it splashes up. But asteroids cool down very quickly which is why craters have rings of dust lining the edge of the crater.  Volcanoes create outgassing and releases important gases like water vapor and carbon dioxide that helps make up our atmosphere. Plate tectonics create mountain ranges and gave the "puzzle piece" like appearance to the continents because tectonics pushed the continents away from each other. Erosion is also important because it builds things. Some examples of erosion are the Grand Canyon and the sand dunes in deserts.   

The Greenhouse Effect/Cooling Rates
The ozone is very important because it protects us from the Sun's rays but CFC's from hairsprays and other human activities are destroying it. 
The smaller a planet is the faster it cools off. If there is no heat a planet is "dead" because it needs the heat's energy to keep life existing on Earth.  
Surface area-to-volume ratio for cooling:

4πr² 

4πr³

   3
 But afterwards, when canceling is complete, you are left with:

3

r

Earth as a Living Planet
The Earth has four important factors to help life exist on Earth: Surface liquid water, atmospheric oxygen, plate tectonics, and climate stability. Liquid water is important because it is essential to life, atmospheric oxygen is important because photosynthesis creates lots of oxygen and that oxygen helps create the ozone layer, plate tectonics are important for the carbon dioxide cycle, and for climate stability it needs the carbon dioxide cycle because the carbon dioxide cycle acts like a thermostat for the Earth. 
Conclusion
We were told to study for the exam and class ended early.