Final Post

Astronomy- My favorite topic while studying the solar system was learning why Earth's seasons occur. I always thought it was because Earth moved closer and farther away from the sun at certain times of the year. This is not true. Earth is always the same distance from the sun. The Earth rotates at a 23.5 degree tilt on its axis. It is because of this tilt that seasons occur. The Earth, season wise, is divided in to two parts. The half's are the Northern Hemisphere and the Southern Hemisphere. During one half of the year, the northern hemisphere receives more direct sunlight. This is summertime. During the other half of the year the southern hemisphere receives the most direct sunlight. When one hemisphere experiences summer, the other experiences winter. It is always warm around the equator because due to its middle position, it always receives direct sunlight. The cause of the seasons is very interesting.

Weather and Climate- My favorite part in the weather and climate unit was learning about the layers of Earth's atmosphere. Earth's atmosphere is made up of 6 different layers. The first layer is the troposphere. The troposphere is 8-16 kilometers thick. It contains 75% of the atmosphere's mass. All of Earth's weather occurs in this layer. The second layer is the stratosphere. The stratosphere is colder on the bottom than the top. The ozone layer is in the stratosphere. The third layer in the atmosphere is the mesosphere. The mesosphere is the middle layer of the atmosphere. It begins 50 km above the surface of the Earth and ends 80 km above the Earth. The top layer of the atmosphere is called the thermosphere. The thermosphere extends from 80km to outer space. The thermosphere is divided into two different sections. The first layer is called the ionosphere. It extends from 80km- 400km above the earth. The second section is the exosphere. The exosphere begins at 400km and extends thousands of kilometers into space. Learning about the layers of the atmosphere was fascinating.


Geology- My favorite part of this unit was learning about the layers of Earth. The first layer of the Earth is the crust. The crust is the crust is a layer of solid rock that includes both dry land and the ocean floor. The crust is 5-70 km thick. The next layer is the mantle. The mantle is made up o hot but solid rock. overall the mantle is 3,000km thick. The mantle is divided int o three different layers. The layers form top to bottom are the Lithosphere, Asthenosphere, and the lower mantle. The next layer is the core. The core is divided into two different layers. The outer and inner core. The outer core is made up of liquid nickle and iron. The inner core is a dense solid ball of nickle and iron. Learning about the layers of the Earth was cool and exciting.


Weathering and Erosion- My favorite part about this unit was learning about how weathering and erosion work. Weathering is the process that breaks down rock and other substances at Earth’s surface. Weathering works in a couple of different ways. There is mechanical and chemical weathering. Mechanical weathering is he type of weathering in which rock is physically broken into smaller pieces. There are a few different causes for mechanical weathering. These causes are freezing and thawing, release of pressure, plant growth, actions of animals, and abrasion. Chemical weathering is the type of weathering that breaks down rock through chemical changes. Chemical weathering also has a few different causes. These causes include the action of water, oxygen, carbon dioxide, living organisms, and acid rain. Erosion is the removal of rock particles by wind, water, ice, or gravity. After weathering breaks rocks down, erosion carries the pieces away. Learning about how weathering and erosion was the best part of this unit.

Earth's Water- My favorite part of this unit was learning about the steps in treating drinking water. The first step is the first filtration. In the first filtration, fish, trash, and leaves are removed from the water ass it travels through screens. the second step is coagulation. In coagulation Alum is added to the water to form sticky flocs. Particles of mud and bacteria stick to the flocs. The third step in the process is the settling basins. All the water and the flocs is drained into settling basins. The forth step is a second filtration. Water is forced through sand and gravel to remove algae, chemicals, and bacteria. Chlorination is the fifth step in the treating process. In this step chlorine is put into the water to kill any remaining organisms. The sixth step is aeration. During aeration air is put through the water taking away unpleasant odors and taste. The seventh and final step is additional treatment. In this step, sodium or lime is added to soften hard water. Also, fluoride is put in to prevent tooth decay. This was the most interesting part of Earth's water unit.

This is my final post on my page. I hope you have enjoyed following my 8th grade page. 8th grade has been challenging and fun year. I have had a lot of fun creating this blog. Well, I'll see you later.