Consider these discussion questions based on chapters 7-8 (see attachements).  Answer the questions , and reply to  four other students.

PAGE #1
1) Comment what you learned about the Data of the Earth such as the rotation rate, revolution rate, albedo, oblateness, escape velocity, etc.  What do you find surprising or new that you didn’t know before?  What do you still not understand?  Do you understand why we have a Leap Year every 4 years but we have to skip it every once a while, which is called the Gregorian Correction.  Do you understand what Escape Velocity, Gravity and Oblateness, and Albedo mean?  Do you think human activity on Earth can eventually alter the albedo of Earth and cause drastic changes to its Temperature?  Also, about the interior of the Earth and how earthquakes help us analyze the interior of the earth?  Do you understand the difference between Longitudinal and Transverse waves and which earthquake wave is transverse and which longitudinal?  Why is the outer layer of the core liquid but the inner core turns back to solid?

2) What have you learned about the surface of the Earth and its atmosphere and magnetic field that is new for you or help you understand something you didn’t know before?  Do you think eventually Los Angeles will split off from the rest of United States and be close to San Francisco, does this prospect scare you?  Does Fracking help prevent a major earthquake by causing bunch of smaller ones?  Do you understand how Plate Tectonics helps explain how mountains, valleys, trenches and rift valleys are created and why some people say that planets without plate tectonics are not habitable?  How about the magnetic field of Earth, how often does it switch and is it dangerous when it switches?  Have you ever seen an aurora and if no, would you one day like to see one?  What do you still have questions about or would like to know more about it?  What does our atmosphere do besides helping us breath in terms of climate regulation?

PAGE #2
ANSWER TO THESE FOUR STUDENTS

#1
  I knew that our planet was unique in how as far as we know it is the only one that contains life. But after learning more about the earth I realized how many characteristics the earth actually has. The rotation rate of the earth is 24 hours, which is one day on earth, the time it takes to rotate on it’s axis giving us night and day. The revolution rate of the earth is 365.25 days, which is the amount of time it takes for the earth to orbit around the sun and is one earth year. The albedo of the earth is 37% which means is the ratio of energy the earth reflects back into the solar system that it receives from the sun. So since the earth’s albedo is less than 50% this means the earth absorbs more than it reflects. The oblateness of the earth is .0034, and when a planet has an oblateness of 0 it would mean it is a perfect sphere. Since planets spin on their axis, the shape changes and it will get slightly wider, so most planets will not have an oblateness of 0, just close to spherical but not quite. The earth’s escape velocity is 11 km/s which is the amount of force/speed it will take to exit earth’s atmosphere due to earth’s density and gravity. Interesting enough, I didn’t know that planets had such a thing as an albedo, and that would be the determination of how much they absorb and how much they reflect. Earth experiences Leap years every 4 years due to the revolution amount being 365.25, we have to have leap years in order to make up for those .25 missing days since each year is 365 days which is also known as the Gregorian Adjustment. I do believe that human activity on earth can alter the albedo, considering global warming and greenhouse gases. The way we live, we exert more CO2 into the atmosphere which can possibly create the albedo to alter, earth has been getting hotter. When the earth experiences earthquakes, it helped us understand the internal layers of the earth and which are solid or liquid. Earthquakes release primary and secondary waves. Primary waves are longitudinal (these move back and fourth) and these waves can travel through solids and liquids. The secondary waves are transverse waves (move up and down) and only move through solids. So when an earthquake is set off, the primary waves are sent to all ends of the earth because the waves can travel through solids and liquids, the secondary waves were cut off by the core, showing us how part of the core is liquid since the secondary waves cannot travel through liquids, only solids. The very inner core of the earth is not liquid though, it turned back to solid due to the change in temperature and pressure. The pressure is so high at the core that the melting point is higher than the temperature, therefore allowing the core to remain solid. The outer liquid core is the opposite situation, the melting point is lower than the temperature, therefore allowing this part of the earth to melt, creating the liquid core.

Ive learned that Earth’s magnetic field, also known as the geomagnetic field, is the magnetic field that extends from the Earth’s interior out into space, where it interacts with the solar wind, a stream of charged particles emanating from the Sun.  Which protects us from solar flares, acts as a shield against those particles. The strongest magnetic field is the south magnetic pole. I believe that one day Los Angeles will split off from the rest of the United States but not any time soon so it would not worry me because it would not be in my lifetime.  In my opinion I feel that fracking will help prevent from having major earthquakes because we would have smaller ones and it will help release pressure from the tectonic plates. Yes because when the plates move they collide and make mountains and when they move apart they make valleys, trenches and rift valleys. They say this because without plate tectonics the earth wouldnt look they way it does today. Yes if the earth switches it will be dangerous because we would be having earthquakes and rapid climate change and species extinctions and it varies there is not set day or time it just happens randomly after hundreds and thousands of years . I have never seen an Aurora before and I would love to see one. I would like to know is there any more planets with plate tectonics as earths or is earth the only one. The atmosphere helps us by blocking out rays from the sun It traps heat, making Earth a comfortable temperature and it sun’s harmful ultraviolet radiation

#2
I learned a lot of information about the earth in this lecture! It reminded me of middle school earth science where I had learned that the earth was tilted on an axis and there also existed a magnetic pole that was different. I could not comprehend those ideas before! I had heard people saying North and True North and I didnt understand. However, after this lecture I learned that what people referred to one North for the magnetic pole and the True North to the Geometric Axis where the earth rotates. It used to be so confusing before! But now I understand that both of those axis are separated by ~11 degrees from here in Los Angeles.

The idea behind leap year also really surprised me on what it truly meant. For a typical year consisting of 365.25 days is broken down into 52 weeks time 7 days per week give us 364 + 1 days only so the way the Gregorian calendar adjusted it consists of the fact that for one day of the month of a particular year will always change the day of the week the following year. And so every 4 years, there is an extra day for that year making it 366 days instead of 365 days per year, which is given in the month of February as February 29th. I see that the reason why we have a leap year every 4 years if due to the quarter of a day 365.25 days per year. Thus, four quarters of a day added up make 1 whole day making it 365 +1 = 366 days for that 4th year. It’s really neat stuff!

#3
Some of the data I learned about earth, it makes one revolution or one complete orbit of the sun in about 365.25 days. The rotation rate or length of a sidereal day -23 hours, 56 minutes, and 4 seconds. The average Albedo of earth is an average of 37% of the energy that it receives from the sun. The earth’s escape velocity is 11km/s=25,000 mph, and its oblateness is .0034 and surface gravity is 1.0. Finding out that the reason we have a leap year every four years is to make up for the lost .26 days, this was something new I learned.  I did a bit more research and escape velocity is the speed needed for an object to escape from the gravitational influence of a massive body. Gravity is the force that attracts a body toward the center of the earth, or toward any other physical body having mass. Oblateness is having an equatorial diameter greater than the distance between poles. Albedo is the reflectivity of a surface, meaning a surface with a high albedo reflects a lot of solar radiation from the sun back into the atmosphere, a surface with a low albedo it reflects little solar radiation, therefor it absorbs it instead. Human activity will eventually alter the albedo of earth, an example is that there has been information that potential for human activities to increase the temperature of the Earth through greenhouse gas emissions has been describes and calculated, which means humans are warming the climate. Earth’s interior can be analyzed by earthquakes by studying their seismic waves, which are sent through the earth during earthquakes. The seismic waves can tell us a lot about the internal structure of the earth because these waves travel at different speeds in different materials, two types of waves that travel through earth are p-waves and s-waves. The difference between Longitudinal waves and Transverse waves is that Longitudinal waves the motion of the medium is parallel to the direction of the wave, and Transverse waves the most of the medium is a right angles to the direction of the wave.

Something new I learned about the magnetic field of the earth is that it allows us to navigate in the ocean and air. It can be looked at as sort of a force field that encompass the earth and protects our planet from solar radiation. I think watching the movie San Andreas definitely scared me a bit as I do see it happening, yet if it does I do not think Los Angeles will split off and fall into the ocean, but it will one day be adjacent to San Francisco. Fracking does not help prevent major earthquakes, the injection of waste water and salt water into the surface can cause earthquakes that are large enough to be felt and may cause damage. The magnetic field of earth’s switches varies, and it can trigger massive earthquakes, rapid climate change and species extinctions. I have never seen an aurora but I will like to see one, it will be very awesome to see this kind of light display. The atmosphere helps to protect living organisms from genetic damage by solar ultra violet radiation, solar wind and cosmic rays. The atmosphere through the hydrological cycle, plants and animals receive the water they need to survive.

#4
What I learned about the Earth rotation takes 24 hours and the revolution rate is 1000 miles per hour. The albedo of Earth is .37. The oblateness of Earth is 0. The escape velocity is 11km/s or 25,000 mph to escape the atmosphere. What I found surprising is how many miles it takes to leave the earth if you can potentially fall back to the Earth. The reason we have a leap year every 4 years is to make up the lost 26 days of the entire year. The escape velocity is how many miles it takes to escape the atmosphere and into space. Gravity is like a natural phenomenon by all mass and energy being brought towards each other. Oblateness is the equatorial diameter greater than the distance between poles; compressed along or flattened at the poles. The albedo is the light reflected in the sun by a planet. Human activity can alter the albedo because of the Co2 that has been brought by humans. The interior of the Earth is made of the crust, next to the mantle, then the liquid outer core and in the center is the solid inner core. Earthquakes help us analyze the interior of the Earth by the P-waves colliding and later dissolving. P-Waves are longitudinal that travel through solids and liquids at 6-13 km/s. S-waves are transverse that only go through solids that are 3-7 km/s. The outer layer is liquid, the temperature is above the melting point and the inner layer rises to their melting point because of the pressure of the earth.

The surface of the Earth has plate tectonics and is constantly in motion. On Earth, Humans are currently living in the Troposphere and extend to the clouds. Above is the Stratosphere where it contains the ozone layer and above that layer is the mesosphere, a layer that helps us by bribing most meteors. The ionosphere is the outermost layer and is the hottest because it receives direct sunlight from the sun. Los Angeles can spit the rest of the United States and I dont mind because we can be our country states but if we do get stripped away, the land can potentially have more tsunamis. Fracking does help prevent major earthquakes because it monitors seismic activities making earthquakes smaller that it cant be detected. Plate tectonics helps make mountains, valleys go through a phase of divergent, convergent, or transform boundaries. I would like to see an Aurora and our atmosphere protects us from the sun and its rays and protects us from burning comets.