EQ1: How are the layers of the earth identified and classified?
Seismologists have been about to study the transfer energy in seismic waves to infer what the structure of the earth must be like deep inside. We have yet to reach the mantle. However, I have attached a link below if you are interested in reading about a possible future attempt.
The layers of earth are classified by the following:
Seismologists have been about to study the transfer energy in seismic waves to infer what the structure of the earth must be like deep inside. We have yet to reach the mantle. However, I have attached a link below if you are interested in reading about a possible future attempt.
The layers of earth are classified by the following:
- composition (what it is made of)
- temperature (how hot it is)
- state (if it is solid, liquid/molten)
- density (how tightly packed its particles are)
EQ2: How are density and convection related?
Vocabulary:
convection
convection cell
fluid
molecules
You have learned that cold air rises and hot air sinks. This is because heat causes particles to expand and separate making them less dense. Things that are less dense float on the particles that are more dense. When heat is removed from objects the particles slow down and become more tightly packed. This causes an increase in density. Things that are more dense sink.
Think of a water in a pot on the stove. The water is resting in the pot. When you turn the stove eye on the water heats up and you can begin to see movement. Eventually, some of that water will vaporize as it becomes less dense. It literally floats right out of the pot.
You should have learned in sixth grade about convection in the atmosphere. Convection also happens inside our planet. The core is super hot. As particles in the lower mantle are heated by the core, those particles begin to rise. The further they move outward from the center of the earth, the cooler they become. As they cool down the particles become more dense and slowly sink back towards the core. This happens in cyclical patterns. The constant uneven heating of the earth keeps the mantle shifting. As the mantle shifts, the crust shifts with it. The crust is floating on the mantle and is controlled by the motion of the mantle. Motion in the mantle occurs because of changing densities due to uneven heating that creates a cycle of convection.
Vocabulary:
convection
convection cell
fluid
molecules
You have learned that cold air rises and hot air sinks. This is because heat causes particles to expand and separate making them less dense. Things that are less dense float on the particles that are more dense. When heat is removed from objects the particles slow down and become more tightly packed. This causes an increase in density. Things that are more dense sink.
Think of a water in a pot on the stove. The water is resting in the pot. When you turn the stove eye on the water heats up and you can begin to see movement. Eventually, some of that water will vaporize as it becomes less dense. It literally floats right out of the pot.
You should have learned in sixth grade about convection in the atmosphere. Convection also happens inside our planet. The core is super hot. As particles in the lower mantle are heated by the core, those particles begin to rise. The further they move outward from the center of the earth, the cooler they become. As they cool down the particles become more dense and slowly sink back towards the core. This happens in cyclical patterns. The constant uneven heating of the earth keeps the mantle shifting. As the mantle shifts, the crust shifts with it. The crust is floating on the mantle and is controlled by the motion of the mantle. Motion in the mantle occurs because of changing densities due to uneven heating that creates a cycle of convection.
EQ3: What evidence supported Alfred Wegener's hypothesis of Continental Drift?
Vocabulary
Lithosphere: "rock" sphere; the outer most layer of solid rock that includes the crust and the upper-most portion of the mantle
Asthenosphere: a plastic-like region of the mantle directly below the lithosphere; convection in this portion of the mantle causes plates to shiftTheory of Pangaea: Theory that at one point in time the continents were connected as one giant landmass or super-continent surrounded by one super-ocean named Panthalassa
Theory of Continental Drift: Hypothesis proposed by Alfred Wegener and rejected. Evidence later supported his claim. The theory suggests that the continents were joined like a puzzle and drifted gradually (approximately 2cm/year) to their current location.
Theory of Plate Tectonics: Theory that the lithosphere is broken into massive sections of floating rock that moves gradually due to convection within the mantle.
During the 1900's it was observed that the continents appear to fit together like a puzzle. Alfred Wegener shared his idea that the continents might have been attached and slowly drifted to their current location. This idea was later named the "Theory of Continental Drift". Evidence that supports this is as follows:
1) Matching land animal fossils were found oceans apart in areas where continents would have been connected.
2) Plant fossils were found in areas where plants do not grow (ex. Antarctica) and they matched up with similar fossils found on other continents where it was proposed that they once joined.
3) Similar rock formations (same sediments and same age) have been discovered oceans apart in areas that would have once touched.
4) Glacial striations were found in Antarctica, South America, Africa, India, and Australia that suggest this area was all close together and covered by ice at some point.
5) The most obvious, the continents appear to fit together like a puzzle.
Vocabulary
Lithosphere: "rock" sphere; the outer most layer of solid rock that includes the crust and the upper-most portion of the mantle
Asthenosphere: a plastic-like region of the mantle directly below the lithosphere; convection in this portion of the mantle causes plates to shiftTheory of Pangaea: Theory that at one point in time the continents were connected as one giant landmass or super-continent surrounded by one super-ocean named Panthalassa
Theory of Continental Drift: Hypothesis proposed by Alfred Wegener and rejected. Evidence later supported his claim. The theory suggests that the continents were joined like a puzzle and drifted gradually (approximately 2cm/year) to their current location.
Theory of Plate Tectonics: Theory that the lithosphere is broken into massive sections of floating rock that moves gradually due to convection within the mantle.
During the 1900's it was observed that the continents appear to fit together like a puzzle. Alfred Wegener shared his idea that the continents might have been attached and slowly drifted to their current location. This idea was later named the "Theory of Continental Drift". Evidence that supports this is as follows:
1) Matching land animal fossils were found oceans apart in areas where continents would have been connected.
2) Plant fossils were found in areas where plants do not grow (ex. Antarctica) and they matched up with similar fossils found on other continents where it was proposed that they once joined.
3) Similar rock formations (same sediments and same age) have been discovered oceans apart in areas that would have once touched.
4) Glacial striations were found in Antarctica, South America, Africa, India, and Australia that suggest this area was all close together and covered by ice at some point.
5) The most obvious, the continents appear to fit together like a puzzle.
EQ4: How are plate movements related to the process of Earth?
Vocabulary
earthquake: a vibration felt in the crust when convection within the mantle causes tectonic plates to shift releasing energy from inside the earth
tsunami: a gigantic wave that transfers energy released from an earthquake that occurs on the ocean floor
There are 3 categories of plate movement. All plate movement causes earthquakes, some with a greater magnitude than others.
1) Convergent boundaries (where two tectonic plates are pushed together by convection in the mantle; if two continental plates collide mountains will form; if a oceanic and continental plate collide subduction will occur causing the more dense oceanic plate to sink and melt, this leads to the formation of volcanoes and deep sea trenches)
2) Divergent boundaries (where two tectonic plates are pulled apart by convection in the mantle; forms rifts that might eventually fill up with sea water; also forms a low elevation mountain ridge on the sea floor)
3) Transform boundaries (plates slide past each other releasing lots of energy from within the earth in the form of large earthquakes; if this happens underneath the sea, it can cause a tsunami)
Vocabulary
earthquake: a vibration felt in the crust when convection within the mantle causes tectonic plates to shift releasing energy from inside the earth
tsunami: a gigantic wave that transfers energy released from an earthquake that occurs on the ocean floor
There are 3 categories of plate movement. All plate movement causes earthquakes, some with a greater magnitude than others.
1) Convergent boundaries (where two tectonic plates are pushed together by convection in the mantle; if two continental plates collide mountains will form; if a oceanic and continental plate collide subduction will occur causing the more dense oceanic plate to sink and melt, this leads to the formation of volcanoes and deep sea trenches)
2) Divergent boundaries (where two tectonic plates are pulled apart by convection in the mantle; forms rifts that might eventually fill up with sea water; also forms a low elevation mountain ridge on the sea floor)
3) Transform boundaries (plates slide past each other releasing lots of energy from within the earth in the form of large earthquakes; if this happens underneath the sea, it can cause a tsunami)