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The supercontinent Pangaea, with its connected South America and Africa, broke apart 200 million years ago. But the continents haven't stopped shifting -- the tectonic plates beneath our feet (in Earth's two top layers, the lithosphere and the asthenosphere) are still traveling at about the rate your fingernails grow. Michael Molina discusses the catalysts and consequences of continental drift.

The supercontinent Pangaea, with its connected South America and Africa, broke apart 200 million years ago. But the continents haven't stopped shifting -- the tectonic plates beneath our feet (in Earth's two top layers, the lithosphere and the asthenosphere) are still traveling at about the rate your fingernails grow. Michael Molina discusses the catalysts and consequences of continental drift.

Map of the tectonic plates that is easy to read.

Huw James took a trek up Mount Etna and decided to show us what actually happens when a volcano erupts!

With a little bit of help from Dr Suze Kundu and using a simple demonstration heating a glass beaker of wax, stone, sand and water we can see what happens when a volcano erupts.

We can actually tell a lot about a volcano looking at the lava that comes out. If the lava is quite dense and thick we know it contains a lot of the compound silica. If it is less dense it has less silica and spreads out a lot more.

Thick lava will generally erupt from one vent and follow one flow down the side of the volcano. Thinner lava, lava that is less dense, generally erupts from the surrounding magma chambers and flows in many different channels.

Have you ever found yourself in the path of molten lava? Has the volcano you're climbing suddenly erupted and you don't know what to do? Well keep watching because Huw James has all you need to know.

The earth is built on tectonic plates that move around on the mantle. Sometimes these plates move around and come together to form mountain chains like the Himalayas, some rub together and set off earthquakes, and some like Mount Etna, interact and one plate goes underneath the other.

A scientist takes a big risk to get a lava sample from the rim of a lava lake.

The map above shows the past century of known earthquakes with a magnitude of at least 5. (There are actually nearly a million earthquakes per year, but most of them are not felt. A earthquake of magnitude 5 might cause damage to buildings.) Each white dot is a quake, of which there were about 72,000, and as you'd expect, you get a sense of plates tectonic boundaries.

According to the study: "For five metals (arsenic, cadmium, lead, manganese and zinc), strong correlations of concentrations in uncultivated soils indicate a common source, suggesting that emissions from the complex may be a major contributor to elevated concentrations of these five metals in uncultivated soils in this area.

We bet you thought that rocks are just rocks, but the truth is there are three different kinds of rocks. Learn the differences between sedimentary, metamorphic and igneous rocks.

A nice, thorough introduction to minerals.

The video introduces mineral properties using common fruit and vegetables as analogies for these five descriptive criteria. The video also demonstrates the orderly crystalline structure of halite (NaCl) using a model made of food (marshmallows and grapes). Comparisons between common substances such as ice and glass versus the mineral definition are made to illustrate the specific nature of the mineral definition.

SciShow takes you down the deepest hole in the world -- Russia's Kola Superdeep Borehole -- explaining who dug it and why, and what we learned about Earth in the process. Don't fall!

Video from Discovery on why Pangea happened.

"When you hear about a volcano erupting, what do you think is going on? If you're like us, you think of red hot chunks of rock being hurled thousands of feet in the air, flows of liquid magma, and plumes of smoke. That's not always the case. Some volcanoes erupt underwater and their smoking hot by-products are immediately cooled. With the Storm in a Cup, you can see what happens underwater on a smaller, safer scale."

ere's a crack in California. It stretches for 800 miles, from the Salton Sea in the south, to Cape Mendocino in the north. It runs through vineyards and subway stations, power lines and water mains. Millions live and work alongside the crack, many passing over it (966 roads cross the line) every day. For most, it warrants hardly a thought. Yet in an instant, that crack, the San Andreas fault, could ruin lives and cripple the national economy.

The distance from the surface of the Earth to its center is 3,959 miles. The thickness of the ocean lithosphere or the relatively solid skin of the earth under oceans is only 41 miles, which in relative terms is much thinner than the skin of an apple.

Interesting video on earthquake locations around the world and connections to fracking.

An interactive map that shows the location of all the earthquakes that have happened in the last day. From the USGS survey.