Change

 Subjected to the pressures and heat within the earth, one kind of rock can transform into something new. These are metamorphic rocks, which after magmatic rock is another of the three kinds of rock.

Sedimentary rocks are the most common kind of rocks, created by eroded rock particles that are collected, compacted, and cemented together into new rock. In short, what was once sedimentary rock and is now sand will one day again be sedimentary rock.

Some of the world's most famous buildings have sedimentary rock as part of their construction. This museum and Parliament Hill join structures like Petra in Jordan, and the Egyptian pyramids, in consisting of sedimentary rock.

A video monitor looks at sedimentary rock landscapes. We'll pick up here tomorrow.

Seismic

 This interactive map is set to show quakes around the world in the last month, with all types of magnitude.

Quakes are profoundly destructive, particularly around urban centers.

Here we have gems, both uncut and finished.

Minerals go hand in hand with rocks, occurring in a variety of ways around the world.

Silicate minerals are very common.

Less common are non-silicate ores and minerals

Volcanic

 Volcanoes shape the world, both being a destructive force, but also building on new land and creating the conditions of fertile soils.

They come in different forms, and create different things during eruptions. This is pillow lava, found at the mid-oceanic ridges.

Basalt columns are the result of the rarely seen flood basalt eruption.

How rare? The last one was fourteen million years ago. Vast stretches of land or seabed get covered by basalt lava.

Shield volcanoes are large and relatively less destructive. The best known examples are the Hawaiian islands.

Cinder cones might be found on the flank of shield or composite volcanoes, and are characterized by a single vent.

Composite volcanoes are large volcanoes, and destructive, with a central vent. Mount Etna is a good example.

A lava dome is a volcano where a dome expands over time around a vent, trapping gases and resulting in a tremendous explosion. Mount St. Helens is a good example.

The results of some volcanoes across history are seen here.

Across the way, the other very destructive force of nature- earthquakes, a result of the plates grinding against each other.

There are quakes in Canada, mostly on the west coast. There was one several years ago here in Ottawa, strong enough that you could feel it rumble. I recall people calmly evacuating the building I was in by a staircase- except for one guy who was running as if his life depended on it, and who would have pushed an eighty year old grandma out of his way. 

Forces Of Nature

 The composition of the earth, with multiple layers going down to a central core, is examined here. At the crust, continental and oceanic plates travel over millions of years.

A video display shows types of volcanoes, which are common at the edges of these tectonic plates.

The Earth is continually recycling and renewing, with new rock emerging.

Oceanic crust tends to sink beneath continental crust. Because of this, continental crust is older.

Here are some examples of zeolites, minerals that form inside basalt lava as it cools. 

Ophiolites are pieces of continental crust that get sheared off and pushed onto land. 

We'll pick up here tomorrow, looking more at volcanoes.