Year 8 term 4 semester exam cards

science

igneous rocks

a rock formed by cooled molten material.

metamorphic rock

a rock formed from a sedimentary, igneous or other metamorphic rocks that have under gone increased temperatures and pressure over a long period of time.

sedimentary rock

rock made from compressed sediment

mineral

a naturally occurring, inorganic substance present in the solid state, made of a specific chemical formula in a definite crystal structure.

rock

an inorganic, solid, and natural substance without any specific atomic structure or chemical composition.

what is the rock cycle?

is the process of how rocks become other types of rocks over huge periods of time

ore

an ore is a mineral with a large amount of useful metal in it.

what are the 2 ways minerals can form?

through the crystallization of magma, or the crystallization of materials dissolved in solution.

properties of a mineral

hardness, luster, cleavage, and streak

hardness

how easily a mineral can be scratched

luster

the shininess of a surface of a mineral

cleavage

the tendency of a mineral to break into a number of smooth planes

streak

the color of a powdered or crushed mineral.

properties of a rock

weight and density, color, layers, crystals and grain.

intrusive igneous rock

is an igneous rock found and formed deep within the earth by magma.

extrusive igneous rock

is an igneous rock found and formed on the surface of the earth by lava.

difference between intrusive and extrusive igneous rocks.

Intrusive rocks tend to have larger crystals, this is because the magma takes longer to cool, so the crystals have more time to form. Extrusive rocks tend to have smaller crystals, This is because the lava cools much more rapidly so the crystals have less time to form.

layers of the earth in order.

crust, mantle, outer core, inner core

lithosphere

is the solid, outer part of the Earth, made of the crust and upper most solid mantle.

Asthenosphere

is the denser, weaker layer beneath the lithospheric mantle made up of the partly molten section of the upper mantle.

kinds of tectonic plates boundries

transform, divergent, and convergent.

transformative boundries

when two tectonic plates slid past each other in opposite directions.

Divergent boundaries

when two plates spread apart from each other.

convergent boundaries

when a two tectonic plates go against each other and one goes

continental drift

is the idea that continents are continually moving and have significantly changed positions over millions of years.

sea-floor spreading

that the middle of the ocean is spreading apart, moving very slowly in opposite directions.

energy

energy is a massless entity that causes things to happen. It is the ability of an object to do work.

kinetic energy

is the energy of moving things

potential energy

energy that is stored and could be used

types of kinetic energy

mechanical, electrical, light, thermal, sound (remember M.E.L.T.S)

types of potential energy

gravitational potential energy, chemical potential energy, elastic potential energy

Law of conservation of energy

energy cannot be created or destroyed, it can only be transformed of transferred.

conduction

passing kinetic energy from one substance to another by direct contact

convection

is the transfer of heat by the movement of a fluid (gas or liquid) between areas of different temperatures

radiation

the transfer of heat across space or through another substance without touching it in the forms of waves/rays.

magma

molten rock underground

lava

molten rock exposed at the earths surface

what causes seismic waves?

they are caused by a sudden movement of materials within the earth

P-waves (primary waves)

they are the fasted wave that travels through the inside of the Earth through solid and liquid. It reaches the seismic station first and moves the rock in a push-pull compressional wave.

S-waves (secondary waves)

they travel through the inside of the earth through solids only, it reaches the seismic station second. It moves rock up and down perpendicular to the wave.

what are fossils

is an organism preserved in a rock.

how do fossils form

fossils form when an organism dies, and it gets covered by sediment then over millions of years, as the sediment builds up, it compacts and cements turning it into a sedimentary rock, which preserves the organism from weathering and predators.

how do you date fossils

You can date them by using comparative dating, this compares the different layers of the Earths sediments, bottom being the oldest and top being the youngest. Another way to date fossils is using radioactive dating, you do this by measuring the amount of radioactivity left in rocks

pangea

Pangea was a super-continent, and the idea that the all the continents were once connected.

order of pangea

Permian, Triassic, Jurassic, Cretaceous, Present day.

effect of transformative plates

earthquakes

effect of convergent plates

trenches, volcanoes, and mountains

effect of divergent plates

rift valleys, and ocean floor spreading

rift

is a linear zone where the lithosphere is being pulled apart