Rocks contain naturally occurring, non-living substances called minerals. 

Minerals are rare and are either:

1. Elements (made of 1 type of atom)

2. Compounds (combinations of  bonded atoms) 

Minerals are not only found in rocks, but they are also found in your body, and dissolved in water (like iron and potassium)!

Minerals can be identified 5 main ways:

1) Colour & Streak

2) Hardness 

3) Shape & Crystals

4) Lustre

5) Cleavage & Fracture

Some minerals can be identified by looking at the colour of the surface.

One Mineral may have several colours.

When two different minerals appear to have the same colour, streak can be used to show the colour of the powder form of the mineral

Cleavage is when minerals split along the flat surfaces of the crystals

Fracture is when minerals break along uneven surfaces

• Mica has cleavage because it breaks in smooth flat sheets

Some minerals will react with substances like acids

Calcium carbonate (aka chalk) reacts with acids and produces a new gas, so it bubbles

Another chemical property is that metals corrode when exposed to oxygen in the air.

• This is called rust, or oxidization 

75% of the rock on the Earth’s surface is sedimentary

Visible layers of sedimentary rock are called strata

Types of sedimentary rock include

Shale comes from fine clay or mud

Sandstone comes from broken down quartz

Conglomerates are pebbles and small stones cemented together

Limestone is organic sedimentary rock, containing fossils

Rocks and rock types can be identified by the minerals found in them as well as by their appearance.

Mechanical Weathering is the physical break-up or disintegration of rocks.

For example, gravity causes rocks to fall down a cliff and break apart. 

Rocks rolling down a slope or in a fast-moving stream rub and bump against each other, becoming smoother and more rounded.

Chemical Weathering breaks down minerals through chemical reactions. 

Some material may be dissolved, other materials are weakened. Rocks react with water, with other chemicals dissolved in water, or with gases in the air.

• An example of chemical weathering is acid rain, which contains dissolved chemicals from air pollution. Acidic rain reacts with some rocks such as limestone. The rock material dissolves easily in the water and washes away.

• Biological Weathering is the physical or chemical breakdown of rock caused by living organisms, such as plants, animals, bacteria and fungi.

• For example, when a plant root wedges into a rock by forcing its way into a crack. As the root grows and expands, so does the crack, and the rock is pushed apart until it eventually crumbles and breaks.

Erosion is the movement of rock and mineral grains from one place to another.

Sedimentation is the building up of rocks and minerals.

Glaciers, gravity, wind and water are the main causes of erosion

When different layers of Sedimentary rock wear away interesting formations can be made.

The crust is the top layer of the Earth. It also includes the minerals in the rocks below it.

Over the Bay of Naples in S. Italy, has erupted over 30 known times. 

Its most famous eruption was in A.D. 79, when a multiday eruption of lava and ash covered the cities of Pompeii and Hurculenium in ash. 

Pliny the Younger, author of the only surviving eyewitness account, described a sudden explosion followed by blankets of ash that fell on people as they tried to escape. 

The total number of Vesuvius' victims will most likely never be known, but archeologists are aware of at least 1,000.

Vesuvius has not erupted since 1944 because it was plugged during its last volcanic eruption.

Scientists are concerned of this plug because tremendous pressure is building under  Vesuvius!

Scientist predict when it does erupt ash and dust will spew 1.5km high!

In 1883, the volcano Krakatoa erupted with 13,000 times the power of an atomic bomb. 

The sound is said to have been heard thousands of miles away. 

Hundreds in a nearby Sumatran town died from flaming ash burning their homes.

Many more were washed away by resulting tsunamis.

An estimated 36,000 died.

Krakatoa collapsed back into the ocean but a new island  began to form in 1927, and it still occasionally spits lava into the sky. 

It's been dubbed Anak Krakatoa, or Child of Krakatoa

Mount St. Helens showed seismic activity for 2 months before eruption, after 120 years of dormancy. 

At 8:32 a.m. on May 18, 1980, a 5.1 earthquake triggered a sideways blast that swept the mountain's north face away in a landslide that shot hot ash and stone out  25km  at over 480kmph.

A mushroom-shaped plume of ash shot 16 miles into the air, eventually covering three states. 

Complete darkness covered Spokane, Wash., 400km away. 

Black rain of ash coated a huge area with a fine gray powder. 

57 people & thousands of animals were killed, and 320km2 of forest were lost. 

The Volcanic Explosivity Index goes to 8. The 1815 eruption of Mount Tambora rated 7. 

10s of 1000s were killed by the eruption and tsunamis, starvation and disease caused by it.

The largest volcanic eruption in recorded history.

Changed the climate so even crops in Europe and North  America failed.

1816 became  known as "the year without a summer".

Mauna Loa, on the Big Island of Hawaii, is the biggest and one of the most active volcanoes in the world.

Since 1843, Mauna Loa has erupted 33 times, most recently in 1984.

At 97 kms long and 48 kms, Mauna Loa, the name of which fittingly means "Long Mountain" in Hawaiian, takes up about half of the Big Island. 

Its mass also amounts to 85% of all the other Hawaiian Islands combined.

Fossils are preserved impressions in rock that tell us when, where, and how organisms lived millions of years ago.