why do tectonic plates move for kids
Take a minute and think of your favorite puzzle. Better yetвhave you ever built a 3-D puzzle? I want you to imagine a 3-D puzzle of the Earth made up of different sized pieces. Do you have that imaginary puzzle in your mind? You have just visualized your first concept of plate tectonics! Before understanding the entire theory of plate tectonics, we need to take a look at the different layers of the Earth. The Earth is made of of three generic layers: the outside is called the crust, below the crust is the mantle, followed by the innermost core. The crust is just how it sounds: a rigid, cool layer, very much like the crust of your favorite pie! Just like the pie may have a nice, warm, gooey inside, the Earth's crust floats on top of a layer similar to that of the pie. This layer is made up of hot, partially melted rock and is called the mantle. The melted rock in the mantle is constantly moving underneath the crust because of uneven heating, or
convection currents. The core is the innermost layer that's extremely hot and is the energy source for the uneven heating of the mantle's convection movement. Let's get back to visualizing the outer layer of the crust. This is a solid, rigid layer that is broken up into puzzle pieces that float on an unstable molten layer of the mantle. The idea that these different 'puzzle pieces,' called tectonic plates, are constantly moving and changing the surface of our Earth is a simplified version of the theory of plate tectonics. The theory of plate tectonics is one of the most important theories in the history of Earth science because it gives reasoning to what causes earthquakes, volcanoes, and the ever-changing surface of our planet!
Innovative technology in the 1950s allowed scientists to use sonar (sound waves) to capture an image of the bottom of the ocean. Before this technology, most people assumed that the bottom of the ocean was completely flat and smooth, much like the bottom of a swimming pool. Once scientists were able to see what it really was like, there were astonished! They saw mountains, valleys, ridges, trenches, and volcanoes, all underneath the water! Have you ever watched something simmering on the stove? Well youвll see steam rise, and if you put on a lid it will actually boil over. If you turn the heat down, then the water and the steam heat drops too. This is how tectonic plates work. Read on for more. What are Tectonic Plates? Deep beneath the surface of the Earth, heat rises from the core, which is the centre of the Earth, through the mantle, which is the next layer and then it reaches the crust. It comes up slowly, but it actually moves the mantle. The mantle rises beneath the Earthвs crust before it spreads sideways and then cools again. One itвs cooled down it sinks again. This is a very slow, but constant movement that has broken the lithosphere, which is the hard part of the Earthвs surface which includes the crust and the upper mantle, in loads of places, which then divides the Earthвs crust into tectonic plates.
This happens over millions of years, and itвs called continental drift. In fact the Earth only moves about 15cm a year. Most of the Earth is covered by seven major plates and another eight or so minor plates. The seven major plates are the African, Antarctic, Eurasian, North American, South American, India-Australian, and the Pacific plates. Some of the minor plates include the Arabian, Caribbean, Nazca, and Scotia plates. Tectonic plates are nearly 100km thick. Wow, thatвs thick; we wouldnвt want to get caught under one of these! There are actually two main types of tectonic plates, which are oceanic and continental. Oceanic - oceanic plates are made of an oceanic crust called вsimaв. Sima is made mostly of silicon and magnesium. Ah, so thatвs where it gets its name from. Continental - continental plates are made up of a continental crust called вsialв. Sial is made up of silicon and aluminium. Yep, understand the name here too! If you wanted to see the tectonic plates moving, then the best place would be at the boundaries of the plates as this is where they move the most. There are three types of boundaries. Convergent Boundaries в this boundary is where two tectonic plates push together. Sometimes theyвll get a bit sneaky and one will move under the other. This is called subduction. Now thatвs a word to impress your teacher with! Even though the movement is slow, convergent boundaries can be areas where mountains and volcanoes form, and there can also be a lot of earthquake activity.
Divergent Boundaries - a divergent boundary is one where two plates actually get pushed apart. The area on land where the boundary is found is called a rift. New land is created by magma pushing up from the mantle and cooling as it reaches the surface. Transform Boundaries - a transform boundary is one where two plates slide past each other. They obviously arenвt too keen on meeting up. These places are called faults and you often find a lot of earthquakes in these areas. Did you know that 250 million years ago all the continents were joined together? This made up one massive continent called Pangaea. The Red Sea was formed where the African and Arabian plates pulled apart. Now this is pretty cool, the rift is getting larger and some people say that the Red Sea will one day from an ocean. One of the most famous transform boundaries is the San Andreas Fault in California. This plate is the cause of many, many, many earthquakes! The Mariana Trench is the deepest part of the ocean. It was made by a convergent boundary between the Pacific Plate and the Mariana Plate. The Pacific Plate is moving under the Mariana Plate. Scientists can now track how tectonic plates move using GPS. Good old GPS! The Himalayan Mountains, including Mount Everest, were formed by the convergent boundary of the Indian Plate and the Eurasian Plate. So, now you should know everything there is to know on Tectonic Plates. Itвs pretty interesting donвt you think, these massive plates moving around the Earth?
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why do tectonic plates move for kids