earth science

What is a rock?

A solid, naturally occuring substance made up of a mixture of minerals.

What are rocks with interlocking grains more likely to be?

Hard and non-porous (leaving no empty spaces for water and air to enter).

What is a sedimentary rock?

Rocks formed on the Earth’s surface from the buildup and sticking together of sediments. They can also be composed of dead animals and plant remains.

Give some examples of sedimentary rocks.

Coal, sandstone, conglomerate, limestone, chalk

Sandstone

Conglomerate

Limestone

Chalk

How long do sedimentary rocks take to form and what are their layers called?

1000s to millions of years - layers called ‘beds’

Define sediments.

Materials that settle to the bottom of a liquid.

Define strata.

Distinct, horizontal layers or beds of sedimentary rock that have been deposited in a sequential manner.

Are sedimentary rocks porous?

Yes, and most are soft and easily scratchable.

Describe physical weathering.

Occurs because of temperature changes. In freeze-thaw weathering, water gets into a crack in a rock. When it is very cold, the water freezes, forming ice.
Ice takes up more space than liquid water, and pushes against the sides of the crack - this happens many times, breaking the rock.

In freeze-thaw weathering, water gets into a crack in a rock. When it is very cold, the water freezes, forming ice.

Ice takes up more space than liquid water, and pushes against the sides of the crack - this happens many times, breaking the rock.

Describe biological weathering.

This happens when plants and animals break up rocks.

Describe chemical weathering.

This happens when rain falls on rocks, and acids in the rain react with substances in the rock

Acids in the rain react with substances in the rock

What are the layers of sediments in sedimentary rocks cemented together by?

Other minerals.

What is an igneous rock and what does igneous mean?

A type of rock formed when either magma or lava cools and solidifies. Igneous describes anything related to fire or intense heat.

Define magma.

Molten rock that is trapped beneath the surface of the earth.

Define lava.

Molten rock that has reached the surface.

Describe and give some examples of intrusive igneous rocks. (plutonic)

Formed when magma cools and solidifies deep within the Earth’s crust. Examples include granite, gabbro, dionite and pegmatite.

E.g. granite, gabbro, dionite and pegmatite.

Describe and give some examples of extrusive igneous rocks. (volcanic)

Formed when magma erupts or flows onto the Earth's surface as lava and hardens. Examples include basalt, andesite, rhyolite and obsidian.

E.g. Basalt, andesite, rhyolite and obsidian.

Do extrusive or intrusive igneous rocks cool quicker and why?

Extrusive igneous rocks because they are exposed to cool air or water, while intrusive igneous rocks cool extremely slowly as they are insulated by surrounding rock.

Do intrusive or extrusive igneous rocks have larger crystals and why?

Intrusive igneous rocks as they take a much longer time to cool, giving the mineral atoms plenty of time to migrate and organise into well-defined crystals.

What is each crystal in a rock made up of?

Particles of one specific mineral.

Are igneous rocks porous? Why?

No (generally), because as magma or lava cools, the growing mineral crystals tightly interlock with one another, leaving virtually no empty spaces or gaps between them.

Give some properties of igneous rocks.

They are hard, durable, non-porous, have large, visible crystals

What are sedimentary rocks useful for?

Limestone: Used in road foundations and concrete highways as cement - rich in calcium carbonate, making it easy to crush into gravel

Coal: Fuel source for generating electricity - made of ancient matter compressed for millions of years, concentrating the carbon and making it highly combustible

Coal: Fuel source for generating electricity - made of ancient matter compressed for millions of years, concentrating the carbon and making it highly combustible

What are igneous rocks useful for?

Granite : Kitchen countertops and monuments - Is incredibly hard, scratch-resistant and non-porous

Pumice: Exfoliating skin - highly abrasive, allowing it to scrub away dead skin

Pumice : Exfolitating skin stones - It is highly abrasive, allowing it to scrub away dead skin

What are metamorphic rocks useful for?

Marble : Museum sculptures and luxury bathroom vanities - It is soft enough to carve details into without shattering, yet dense enough to be shiny when polished

Slate : Luxury roofing tiles - its splits cleanly into perfectly flat, waterproof sheets that don’t rot

Slate : Luxury roofing tiles - its splits cleanly into perfectly flat, waterproof sheets that don’t rot

What is a metamorphic rock?

A rock that has been transformed from an existing rock by intense heat and pressure underground. They form over millions of years.

What does foliated mean?

A metamorphic rock that has layers or bands of different minerals visible.

Where does the pressure and heat to make metamorphic rocks come from?

Pressure: From rocks above

Heat: From magma nearby

Heat: From magma nearby

Give some examples of metamorphic rocks.

Migmatite (foliated), sandstone and marble

Sandstone

Marble

What property of gneiss makes it a good material for sea-defences?

It is hard and resistant to erosion.

What is the appearance and structure of a non-foliated metamorphic rock?

Appearance: It looks completely the same all over, without any visible layers, bands, or stripes.
Structure:
The mineral crystals are fused together into a uniform, massive block rather than being flattened into neat lines.

It looks completely

the same all over

, without any visible layers, bands, or stripes.

Structure:

The mineral crystals are fused together into a

uniform, massive block

rather than being flattened into neat lines.

How is marble formed?

Marble starts out as limestone. Marble forms when limestone below the Earth’s surface heats up. The limestone does not melt, but its particles are rearranged.

How is slate formed?

Slate starts out as type of sedimentary rock called mudstone. Slate forms when high pressure underground squashes the mudstone. This squeezes out water, and makes layers of new crystals.

Explain why granite is not porous, based on how it is formed.

Granite is not porous because it is an intrusive igneous rock that forms from magma cooling extremely slowly deep underground. This slow cooling environment allows the growing mineral crystals to interlock tightly with one another.

This slow cooling environment allows the growing mineral crystals to interlock tightly with one another

This dense, overlapping crystal structure leaves no open spaces, pores, or gaps between the minerals, preventing water from soaking into the rock.

Explain why granite has bigger crystals than basalt.

• Granite has larger crystals than basalt because it is an intrusive rock that cools slowly deep underground, giving mineral atoms plenty of time to grow into large structures.

• In contrast, basalt is an extrusive rock that forms on the Earth's surface and cools rapidly. This fast cooling freezes the minerals in place before they can form large, visible crystals.
  

In contrast, basalt is an extrusive rock that forms on the Earth's surface and cools rapidly. This fast cooling freezes the minerals in place before they can form large, visible crystals.

What can rocks with larger crystals and greater hardness appear as?

Shiny or sparkly (lustre).

What is the rock cycle?

The continuous process where the three main types of rock are transformed and transition from one type to another over time.

Define uplift.

When pressures of the Earth’s crust push rocks upwards, bringing them to the surface.

How are metamorphic rocks formed?

Intense heat and pressure

Recrystallisation (heat and pressure cause the minerals inside the original rock to change, align, and grow into new minerals without ever turning back into liquid magma)

Step 1 of the formation of sedimentary rocks/rock cycle (weathering)

Rain, wind and ice break existing rocks down into tiny fragments.

Step 2 of the formation of sedimentary rocks/rock cycle (Erosion)

The wearing down and moving away of sediments from their rock.

Step 3 of the formation of sedimentary rocks/rock cycle (Transportation)

Transport processes move the eroded bits of rock away from the orginal rock (by water, ice, wind or gravity)

Step 4 of the formation of sedimentary rocks/rock cycle (Deposition)

Sediments stop moving and settle down in one place.

Step 5 of the formation of sedimentary rocks/rock cycle (Compaction and cementation)

The joining of deposited sediments - compaction = weight of sediments above squashing them together, cementation = another substance sticking the sediments together

Step 6 of the rock cycle (Heat and pressure)

Further squashing and heating turns the rocks into metamorphic rocks.

Step 7 of the rock cycle (melting)

Intense heating makes the rock partially melt, changing it to magma.

Step 8 of the rock cycle (cooling)

Solidification of the molten (melted) rock to form igneous rocks.

Step 9 of the rock cycle (exposure)

When rocks are brought to the surface, restarting the cycle.

What is a satellite?

Any object that orbits around a larger object in space.

What is a galaxy?

A collection of stars held together by gravity; there are billions of stars in the Milky Way.

What does our Solar System orbit?

A large black hole at the centre of the Milky Way.

What is an exoplanet?

Any planet beyond our Solar System.

What is our nearest galaxy?

Andromeda.

What is a comet?

A huge snowball that orbits the Sun.

What is a meteor?

Bits of dust or rock that burn up as they move through the Earth’s atmosphere and produce streaks of light.

What is a meteorite?

Any meteor that makes it to the ground.

What is sonification?

The process by which a telescope turns data into musical notes or sounds.

How long does it take for light reflected from the Moon vs the ISS to reach us?

Moon - Just over a second

ISS - A fraction of a second

ISS - A fraction of a second

What is the difference between an artificial and a natural satellite?

Artificial : Man-made object placed into orbit by humans

Natural: Celestial body that is naturally occuring and orbits a larger object

Natural : Celestial body that is naturally occurring and orbits a larger object