Year 8 Earth Science - For additional resources visit: http://www.iheartscience.net

1. Earth Science
Sarah Jones
www.wallibs.com

2. Earth’s Structure
www.edplace.com

3. Tectonic Plates
www.edplace.com

4. Igneous Rocks
science.nationalgeographic.com

5. Granite Pumice Obsidian

6. Igneous Rock Properties
• Contain interlocking crystals – held together
strongly which makes the rock hard.
• The crystals have a disorderly arrangement.
• Crystal size depends on how quickly the rock
solidified.
• They never contain
fossils.
news.nationalgeographic.com

7. Igneous Rock Formation
• When magma cools above the Earth’s surface
it forms extrusive igneous rocks – the magma
cools quickly and small crystals are formed.
• When magma cools below the Earth’s surface
it forms intrusive igneous rocks – the magma
cools slowly and large crystals grow as the
magma solidifies.
The Rock Cycle – Boardworks
http://0.tqn.com/d/geology/1/0/l/N/thundereggs.jpg

8. Basalt Columns
www.americansouthwest.net

9. Sedimentary Rocks
science.nationalgeographic.com

10. Limestone Sandstone Chalk

11. Sedimentary Rock Properties
• Often have layers showing deposition at
different times.
• Often have fossils trapped within them.
• They consist of lots
of small grains and
are often porous
and crumbly.
www.iupui.edu

12. Sedimentary Rock Formation
• Weathering creates small rock fragments
which are transported to the sea where they
are deposited – sediment.
• Dead creatures may then become trapped –
become fossils.
• The pressure of the layers above and the
effects of salt cement the sediments together
– happens over millions of years.
• Rocks formed – sandstone, mudstone and
limestone.

13. • Sedimentary rocks can also be formed by
precipitation.
• Certain minerals are dissolved in seas and lakes.
• These dry up over millions of years.
• The water evaporates and the
dissolved minerals precipitate.
• Rocks formed –
limestone and chalk
The Rock Cycle – Boardworks

14. Metamorphic Rocks
www.nps.gov

15. Marble Slate

16. Metamorphic Rock Properties
• Often have layer structures of crystals – effect
of heat and pressure.
• Usually denser and harder than sedimentary
rocks.
• Sometimes show distortions caused by the
movements that lead
to their formation.

17. Metamorphic Rock Formation
• Formed by the effect of extreme pressure and
temperatures deep within the Earth.
• This changes existing rocks so that new rocks
are formed.
The Rock Cycle – Boardworks
http://23n58e.blogspot.com.au

18. The Rock Cycle
http://www.bbc.co.uk/bitesize/ks3/science/environment_earth_universe/rock_cycle/revision/10/

19. http://www.geologycafe.com/images/rock_cycle_big.jpg

20. Types of Rocks and Minerals
• All rocks are made of two or more minerals.
• Minerals are not made of rocks – minerals are
the same all the way through.
http://www.rocksforkids.com/RFK/identification.html
http://0.tqn.com/d/chemistry/1/0/L/q/fluoritecrystals.jpg

21. Identifying Minerals
• Colour
• Luster
• Specific Gravity
• Crystal Form
• Cleavage
• Fracture
• Tenacity
• Hardness
• Transparency
• Special properties - magnetism, chatoyancy,
fluorescence, odor, streak, burn test, conductivity.
http://australianmuseum.net.au/image/Pyrite-specimen

22. Some of Australia’s Mineral Resources
Iron Ore Bauxite Black Coal

23. Zinc Gold Nickel