Planet Earth 1-3

• The difference between rocks and minerals is that minerals are crystalline, naturally occurring and rocks are made of minerals.
• Igneous rock forms from the cooling and solidification of magma or lava
• Sedimentary rock forms when sediments are compacted together to form layers
• Metamorphic rock forms due to changes in temperature and pressure
• Granite is an example of intrusive igneous rock with large grains
• Minerals can be identified by their lustre, colour, streak, hardness, and breakage.
• The Moh's Hardness Scale is used to measure the hardness of a mineral, ranging from 1 to 10.
• Lustre is how light reflects off the mineral's surface.
• Colour is the most obvious, but least useful, way to identify a mineral.
• Intrusive rock cool slowly in the crust, forming large crystals.
• Extrusive rock cools quickly outside the Earth's crust, forming small crystals.
• Sedimentary rocks form through weathering, erosion, transportation, deposition, compaction, and cementation.
• Shale and Limestone are 2 examples of sedimentary rock.
• Compaction means making the sediments closely and neatly packed together; dense
• Cementation: when new materials glue the sediments together
• Gneiss and schist are examples of metamorphic rocks.
• Weathering: the process of wearing or being worn by long exposure to the atmosphere
• Erosion: the process of sediments being weathered and transported away.
• Deposition: the action of depositing sediments to their resting place.
• Mechanical weathering is when rocks are broken down by the force of water, ice or wind.
• An example of mechanical weathering is the erosion of cliffs by waves or frost-wedging.
• Biological weathering is when the weathering process is controlled by living organisms.
• An example of biological weathering is tree roots cracking rocks.
• Chemical weathering is when chemicals react with rocks to break them down.
• An example of chemical weathering is the decomposition of rocks by acid rain.
• Striation: a long, thin streak, ridge, or groove on a surface, often one of many similar parallel marks made by glaciers.
• The original rock from which metamorphic rock and sediment are formed from is called the parent rock.
• Sediments can be transported through wind (aeolian), water (fluvial), ice (glacial) or gravity (gravitational).