The continental drift theory is a description of how geologists thought continents moved. It essentially postulated that the continents were drifting across the surface of Earth.

Additionally, the continents were said to have once been grouped together into a single supercontinent. Alfred Wegener published a book on this theory in 1915 based on similarities between rocks and fossils found on different continents, fossils of plants in anomalous locations (e.g. tropical plants in frozen Norway), and the shapes of the continents fitting together like a jigsaw puzzle. (Wegener was not the first to propose such a theory though; he credited authors from as early as 1848 who put forth similar ideas.) His idea was rejected largely because he could not propose a plausible mechanism.

The current theory for describing movement of the crust is called plate tectonics. This theory evolved out of continental drift theory, but includes a reasonable mechanism for the movement of the plates. Plate tectonics proposes that solid plates of the crust "float" on a liquid-ish mantle, and convection currents in the mantle push the plates around.

Good question. Most people would call "continental drift" (the idea that continents are moving slowly), more than a theory, since with Global Positioning Systems we can actually measure them moving in real time. (Most move about as fast as your fingernails grow--around an inch or so per year.)

That the continents are moving is an idea that been confirmed over and over again, so scientists have LOTS of confidence in it. Calling it a "theory" is almost insulting--like saying "gravity" is just a theory. Scientists are always cautious about separating facts and theory. Some would say, that nothing in science is "a fact" (absolutely certain, in other words), because for an idea to be scientific it has to have the potential to be proven wrong. So, scientists are never 100% certain that an idea is correct--it's much easier to tell when an idea is wrong.

Continents move because they are attached to bigger structures called plates. The surface of Earth is broken into 20 or so major plates (imagine the shell of a hard-boiled egg which has been cracked--each piece of that shell would be called a plate). Earth's plates are made up of continental portions and oceanic portions. As plates move, they drag along continents with them.

Why do plates move? That's a tricky question. We have some good ideas, but Earth scientists are still debating the details.

I encourage you to read more about plate tectonics--it's fun stuff!

Continental drift theory is the theory on how the world’s land has drifted over a long period of time. Alfred Wegener came up with it in 1912. It makes sense because it explains why animal and plant fossils that look alike are found on different continents that are far away from each other.

200 to 250 million years ago, there used to be one huge supercontinent called Pangea. Over time, due to plate tectonics, the land separated into pieces and rotated, which gives us the 7 continents we have today: Africa, Asia, Europe, North America, South America, Australia, and Antarctica.

Continental drift is the theory that over time, continents move away from each other, thus appearing to have "drifted" across the ocean bed. For example, South America and Africa are gradually moving apart. As they separate, lava flows up in the space they left behind and then hardens into rock, creating the mid-Atlantic ridge.

Continental drift is the theory that the continents have moved across Earth's surface over geologic time and used to be connected or disconnected from where they are now. It has been through several versions, but the one that is now accepted as realistic was put forward in the 1960s, and ports that continents are attached to plates in the Earth's crust that move, thereby dragging continents with them, as a result of convection due to the heat difference between the Earth's interior and the surface. Movement of continents or parts thereof creates earthquakes.

The theory of continental drift was proposed by Alfred Wegener in 1912. His idea was that all of the continents were once in contact but drifted apart. He got this idea from noticing that the shapes of the continents fit together and that there are fossils of similar plants and animals on different continents. Most scientists didn't believe this, because Wegener couldn't explain what would make continents move and because it would be very difficult for a continent to push its way through the seafloor.

In the 50's and 60's the theory of plate tectonics was developed and is currently considered the best explanation for how continents move. The theory of plate tectonics states that the earth has a relatively soft flowing mantle and a crust made of hard plates. The plates float on top of the mantle and move because of circulation in the mantle and because of differences in their own densities. The continents sit on the plates and move with them. This is different from continental drift, because the continents don't move by themselves and don't have to push through the sea floor.