The idea of giant plates of rock moving slowly across Earth's surface is called plate tectonics.
The Development of the Plate Tectonics Theory
1. In 1915 a German scientist named Alfred Wegener said that the continents move very slowly across Earth's surface.
2. He called his idea the theory of continental drift. However, he could not explain it completely.
3. That theory led to the discovery of plate tectonics, which explains that huge plates in the lithosphere are able to move very slowly across Earth's surface.
The plates move very slowly. Their average speed is about 10cm a year. However over millions of years, plates can move thousands of kilometers.
The Development of the Plate Tectonics Theory
1. In 1915 a German scientist named Alfred Wegener said that the continents move very slowly across Earth's surface.
2. He called his idea the theory of continental drift. However, he could not explain it completely.
3. That theory led to the discovery of plate tectonics, which explains that huge plates in the lithosphere are able to move very slowly across Earth's surface.
The plates move very slowly. Their average speed is about 10cm a year. However over millions of years, plates can move thousands of kilometers.
Plate Boundaries
A plate boundary is where one plate meets another plate. Different things happen at plate boundaries. The three types of boundaries are as follows.
1.Converging Boundaries
At converging boundaries, two plates converge, or move toward each other. Sooner on later, they crash into each other. One plate may go over the other. The upper plate may push the edges of the lower plate plate under it. This is called subduction.
At converging boundaries, two plates converge, or move toward each other. Sooner on later, they crash into each other. One plate may go over the other. The upper plate may push the edges of the lower plate plate under it. This is called subduction.
2.Diverging Boundaries
At diverging boundaries, two plates move away from each other, or diverge. Melted rock rises between plates and forms new crust. This usually happens on the sea floor, so it is called sea-floor spreading.
3. Sliding Boundaries
In some places, plates slide past each other so these are known as sliding boundaries.