Explain how continental drift is possible and why it happens?
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Step 1: get recipe or package for traditionally made pudding at the store. The kind that requires you to cook it on the stove.
Step 2: make it per directions and note during the final stages how the pudding behaves.
Your stove is the earth’s core
The pudding that is rising up and bubbling is the mantle.
The surface of the pudding is the earth’s crust. Cool enough to mostly maintain its shape. Practically solid but still being affected by neighboring material, including what’s below it. Heat rises and heated rock is no different. The heat itself causes it to expand and become less dense than cooler rock.
Convection is the result: a circle of heating and cooling of the material. At the surface, farthest from heat source, the rock starts to become more dense again and sink, but is pushed off to the side first. The push is what is forcing the solid surface rock apart at the “seams.” Making it all the way to the top means that the material can join the existing solid crust meanwhile where the force of the flow is less, possibly in a cooler area, some crust is being pushed against other crust and one side slides underneath the other, sinking, and starting the cycle over.
Seams are where volcanoes form. The collision of crust where it’s cooler is where you get earthquakes and mountain ranges as one continent is sliding over the top of the other.
Over time, the surface shape changes as the seams push continents apart or force the other sides of the plates together.
So the crust off the earth (the bit you stand on) is hard and is split into the big chunks called plates these sit on top of the mantle which is incredibly hot rock that is like an incredibly viscous (thick) liquid. The mantle thats closest to the centre of the earth is a lot hotter than the mantle near the crust and because heat rises they swap places. The hot mantle rises and cools and the cool mantle sinks and heats up, this causes a cycle which i think is called convection. When the rising mantle reaches the crust it pushes it a bit which unsettles the plate causing it to move over thousands of years. Hope this helps 🙂
Under high pressure and elevated temperature, even seemingly solid rocks are able to flow and deform like cookie dough or wet clay.
Albeit to the tune of 1-5 cm or so per year. But over hundreds of millions of years, continents can drift apart due to such forces.
This is similar to the process of blacksmithing. When heated, iron can deform like clay, although it takes quite a bit of force to do it, in other words the force of hammer blows.
The outer core of the Earth is still molten. Periodically, hot molten material flows up through gaps and cracks, softening and liquifying certain minerals in the mantle which is otherwise largely solid. This hotter material slowly rises to the surface due to the pressure farther below. This effectively wedges continental plates apart, like using a wedge to split wood.
Because the rocks found in continents are less dense than those in the mantle, they “float” in a certain sense, while the denser rocks created in rift zones tend to be found lower in elevation…that is, in the mid-ocean ridges, underneath a few km of water.
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