Plate tectonics explains how Earth's surface is constantly on the... Show more
Health
Algebra
Calculus 1
Algebra 1
OverigeSign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
1 / 4
Continental Drift and Evidence
Ever wonder why South America and Africa look like they could fit together? That's exactly what scientist Alfred Wegener noticed when he proposed the continental drift theory, suggesting continents move across Earth's surface over time.
The evidence for this theory is compelling. The fit of the continents shows they connect like puzzle pieces. Fossil evidence reveals identical ancient creatures on separate continents, like the mesosaurus (a freshwater animal) found on both South American and African coasts. Similar rock types and structures appear on matching coastlines, forming continuous mountain chains when mentally reconnected.
Perhaps most fascinating is the paleoclimatic evidence - coal deposits in Antarctica indicate it once had tropical swamps and must have been positioned closer to the equator! All this evidence supports the idea that Earth once had a supercontinent called Pangaea.
Did you know? The mesosaurus fossils found on both South American and African coasts are one of the strongest pieces of evidence for continental drift, as these freshwater reptiles couldn't have swum across the Atlantic Ocean!
Plate Boundaries
Plate boundaries are where the action happens in plate tectonics! These meeting points between massive rock slabs create different features depending on how they interact.
Convergent boundaries occur when plates move toward each other. When land plates collide, compression stress creates mountain ranges like the Himalayas. In subduction zones, where denser oceanic crust slides under continental crust, we get deep ocean trenches, volcanic mountain ranges, and volcanic island arcs.
Divergent boundaries form where plates pull apart, creating tension stress. This produces mid-ocean ridges, rift valleys, and new ocean floor. The Mid-Atlantic Ridge between South America and Africa is a perfect example where new crust constantly forms as plates move away from each other.
Transform boundaries occur when plates slide horizontally past each other, creating shearing stress. The San Andreas Fault in California is a famous transform boundary that produces many earthquakes but no volcanism.
Remember: At subduction zones, the denser oceanic plate always dives beneath the lighter continental plate. This is why oceanic crust is generally younger than continental crust - it gets recycled!
Earth's Structure and Density
Earth isn't just a solid rock—it has distinct layers with different properties. The crust is where we live, while the massive mantle (2,900 km) lies below, followed by the outer core (2,250 km) and finally the inner core (1,300 km).
Two important upper layers affect plate movement. The lithosphere includes the crust and uppermost mantle, forming the rigid tectonic plates. Below this, the asthenosphere is a more flexible layer of the upper mantle that can deform and flow.
Density plays a crucial role in plate tectonics. Continental crust is made of granite and is less dense, while oceanic crust is made of basalt and is more dense. This density difference explains why oceanic plates subduct under continental ones at convergent boundaries.
Cool science fact: The movement of Earth's plates is partly driven by convection in the mantle - hot, less dense material rises while cold, more dense material sinks. This works just like a pot of boiling water, but on a planetary scale and moving extremely slowly!
Driving Forces and Hotspots
What actually moves the plates? Two main forces work together. Ridge push is the gravitational force that causes plates to slide down from oceanic ridges toward subduction zones. Slab pull is even stronger—it's the downward pull of a dense subducting plate as gravity drags it into the mantle.
These forces work with convection currents in the mantle that act like a conveyor belt, helping to drag the plates across Earth's surface. Hot material rises from the core-mantle boundary, spreads out beneath the lithosphere, cools, and sinks back down, creating a continuous cycle.
Not all volcanic activity happens at plate boundaries! Hotspots are intensely hot areas in the mantle that punch through the middle of plates. As the plate moves over a stationary hotspot, it creates a chain of volcanoes, with the active volcano directly above the hotspot and a trail of extinct volcanoes behind it.
Amazing example: The Hawaiian Islands formed as the Pacific Plate moved over a hotspot. The Big Island (Hawaii) is currently over the hotspot and still volcanically active, while the older islands to the northwest formed millions of years ago and have since moved away from the hotspot!
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI companion is specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.
Where can I download the Knowunity app?
You can download the app in the Google Play Store and in the Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
Most popular content in AP Biology
Most popular content
Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.9/5
App Store
4.8/5
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user
Discovering EPAC and Tectonic Plates
Plate tectonics explains how Earth's surface is constantly on the move. This fascinating process shapes our planet's landscapes through the movement of massive rock slabs called tectonic plates. Understanding plate tectonics helps explain everything from mountain formation to earthquakes and... Show more
Continental Drift and Evidence
Ever wonder why South America and Africa look like they could fit together? That's exactly what scientist Alfred Wegener noticed when he proposed the continental drift theory, suggesting continents move across Earth's surface over time.
The evidence for this theory is compelling. The fit of the continents shows they connect like puzzle pieces. Fossil evidence reveals identical ancient creatures on separate continents, like the mesosaurus (a freshwater animal) found on both South American and African coasts. Similar rock types and structures appear on matching coastlines, forming continuous mountain chains when mentally reconnected.
Perhaps most fascinating is the paleoclimatic evidence - coal deposits in Antarctica indicate it once had tropical swamps and must have been positioned closer to the equator! All this evidence supports the idea that Earth once had a supercontinent called Pangaea.
Did you know? The mesosaurus fossils found on both South American and African coasts are one of the strongest pieces of evidence for continental drift, as these freshwater reptiles couldn't have swum across the Atlantic Ocean!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Plate Boundaries
Plate boundaries are where the action happens in plate tectonics! These meeting points between massive rock slabs create different features depending on how they interact.
Convergent boundaries occur when plates move toward each other. When land plates collide, compression stress creates mountain ranges like the Himalayas. In subduction zones, where denser oceanic crust slides under continental crust, we get deep ocean trenches, volcanic mountain ranges, and volcanic island arcs.
Divergent boundaries form where plates pull apart, creating tension stress. This produces mid-ocean ridges, rift valleys, and new ocean floor. The Mid-Atlantic Ridge between South America and Africa is a perfect example where new crust constantly forms as plates move away from each other.
Transform boundaries occur when plates slide horizontally past each other, creating shearing stress. The San Andreas Fault in California is a famous transform boundary that produces many earthquakes but no volcanism.
Remember: At subduction zones, the denser oceanic plate always dives beneath the lighter continental plate. This is why oceanic crust is generally younger than continental crust - it gets recycled!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Earth's Structure and Density
Earth isn't just a solid rock—it has distinct layers with different properties. The crust is where we live, while the massive mantle (2,900 km) lies below, followed by the outer core (2,250 km) and finally the inner core (1,300 km).
Two important upper layers affect plate movement. The lithosphere includes the crust and uppermost mantle, forming the rigid tectonic plates. Below this, the asthenosphere is a more flexible layer of the upper mantle that can deform and flow.
Density plays a crucial role in plate tectonics. Continental crust is made of granite and is less dense, while oceanic crust is made of basalt and is more dense. This density difference explains why oceanic plates subduct under continental ones at convergent boundaries.
Cool science fact: The movement of Earth's plates is partly driven by convection in the mantle - hot, less dense material rises while cold, more dense material sinks. This works just like a pot of boiling water, but on a planetary scale and moving extremely slowly!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Driving Forces and Hotspots
What actually moves the plates? Two main forces work together. Ridge push is the gravitational force that causes plates to slide down from oceanic ridges toward subduction zones. Slab pull is even stronger—it's the downward pull of a dense subducting plate as gravity drags it into the mantle.
These forces work with convection currents in the mantle that act like a conveyor belt, helping to drag the plates across Earth's surface. Hot material rises from the core-mantle boundary, spreads out beneath the lithosphere, cools, and sinks back down, creating a continuous cycle.
Not all volcanic activity happens at plate boundaries! Hotspots are intensely hot areas in the mantle that punch through the middle of plates. As the plate moves over a stationary hotspot, it creates a chain of volcanoes, with the active volcano directly above the hotspot and a trail of extinct volcanoes behind it.
Amazing example: The Hawaiian Islands formed as the Pacific Plate moved over a hotspot. The Big Island (Hawaii) is currently over the hotspot and still volcanically active, while the older islands to the northwest formed millions of years ago and have since moved away from the hotspot!
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI companion is specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.
Where can I download the Knowunity app?
You can download the app in the Google Play Store and in the Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
5
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Mock Exam
Quiz
Flashcards
Essay
Similar Content
Continental drift and seafloor spreading
What was the theory of the continental drift? What is the process of seafloor spreading?
Biology9th
Volcano Types Explained
Explore the differences between composite and shield volcanoes, including their eruption styles, features, and key terms. This summary covers essential concepts such as lava types, eruption mechanisms, and volcanic structures, making it ideal for exam preparation and understanding volcanic activity.
Biology8
Most popular content in AP Biology
Most popular content
Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.9/5
App Store
4.8/5
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user