Main content
Big History Project
Unit 4: Lesson 4
4.3—Ways of Knowing: Our Solar System and Earth- Introduction to Geology
- Gallery: Geology
- Alfred Wegener and Harry Hess
- Activity: What Do You Know? What Do You Ask?
- Eratosthenes of Cyrene
- Introduction to the Geologic Time Chart
- Activity: Claim Testing – Geology and the Earth’s Formation
- Principles of Geology
- The Universe Through a Pinhole: Hasan Ibn al-Haytham
- Activity: Lesson 4.3 DQ notebook
- Quiz: Our Solar System and Earth
© 2023 Khan AcademyTerms of usePrivacy PolicyCookie Notice
Activity: Claim Testing – Geology and the Earth’s Formation
Purpose
This activity will help you review the four claims testers and understand how scientists would use them to investigate claims about plate tectonics.
Process
Remember that we are presented with claims in everyday life. Your job in this activity is to evaluate the following claims:
- About 99 percent of the matter in any star-forming gas cloud ends up in a star, and only about 1 percent is left over for planet formation.
- Differentiation is the process by which gravity in the disk spinning around a developing star clumps matter together into planets, asteroids, and other objects.
- Each continent has its own tectonic plate.
- Historians and geologists measure time in very different ways.
Pick one of these claims and decide whether you think it’s true or false. Then, decide what claim tester (intuition, evidence, logic, authority) helps support your assertion.
For Further Discussion
In the Question Area below, do two things:
1. Post your claim, whether you think the claim is true or false, and the claim tester that supports your assertion.
2. Look at someone else’s posting and see if you can find additional claim testers to support that person’s assertion. Respond to their post with the claim tester you’ve found and a description of how it supports their assertion.
Want to join the conversation?
Will the continents come back together like in the past?(6 votes)
Yes! Our seven continents are predicted to become another supercontinent in some of the following hundreds of millions of years. The plate tectonic supercycle reoccurs about once every 400 million years, with the last supercontinent being Pangea which broke up about 335 million years ago, when the dinosaurs were around. When the cycle restarts, it means that all of the oceanic lithospheric plates from the previous cycle would have been recycled (or subducted, melted, and reformed).(6 votes)
Why do we have earthquakes in the middle of continents?If every continent has its own plate , we would only have earthquakes at the plate boundaries(2 votes)
The continents are irregular and may have fault lines in various places due to weaknesses in the crust. One popular example of this is in Missouri: https://en.wikipedia.org/wiki/New_Madrid_Seismic_Zone
There is also human activity causing earthquakes. Fracking has led to a significant increase in seismic activity in previously stable places like Oklahoma. Also mega structures, like China's Three Gorges Dam, change the landscape significantly to also produce seismic activity.(4 votes)
Hanane stars dont form there own gas. They just take gas from any thing it can get.The stars just burn off there gas and they try to get more gas so that they can live.(3 votes)
Yes I do think that there are seperate plates my proof is that if all of the plates were to combine into one during the Earths creation then we would all be in a predicament every time there was an earthquake. Just imagine Japans 8.1,Wouldn't that have been an issue,answer......yes,and also states would count when having there own plate(3 votes)
Each continent has its own tectonic plate.
I think this is false because if there were only 7 plates then we wouldn't have earthquakes of different plates where the earth quake happens colliding. If each continent had its own plate then we wouldn't get earthquakes in places that are in the center of continents.(2 votes)
Differentiation is the process by which gravity in the disk spinning around a developing star clumps matter together into planets, asteroids, and other objects. I think it is true, we have the evidence of a similar process of separation of milk - when the milk is spinning in spechial equipment it is divided into different parts (butter, cream, serum).
Historians and geologists measure time in very different ways. I feel it is true though the authorities say that the way is the same, my intuition think the time is very strange thing and not only the way of measuring of it can be different, itself can be very different in different conditions.(1 vote)
Actually, differentiation is when the earth's layers formed by heavier elements sinking and lighter ones rising.
Accretion is when dust and gas spinning around the early star forms into planetary bodies through electrostatic forms and collisions.(2 votes)
- yes there are two tectonic plates because there have been multiple claims throughout the years of two tectonic plates colliding together creating mountains and other land masses because of there collision.(1 vote)
- I pick the claim that states, Historians, and geologists measure time in very different ways. I believe it is true. I believe it is true because in a video we watched for the assignment the speaker said it.(1 vote)
- stars are a form of gas that burns out eventualy because the gas catches fire(1 vote)
I do believe that historians and geologist measure time in different ways, however do you think that do to the fact that we all live in different continent that our time will be measure differently. also with the sun rotating or us rotating around the sun its hard for all of us to get that morning or sun glow which make us tell time differently then form someone who lives a thousands miles away or more.(1 vote)