New
New
Year 8

Types of rocks

I can use features to classify rocks into different groups and suggest properties of each type.

New
New
Year 8

Types of rocks

I can use features to classify rocks into different groups and suggest properties of each type.

Lesson details

Key learning points

  1. Sedimentary rocks contain distinct grains that are stuck together.
  2. Sedimentary rocks may contain fragments of shell or fossils, or larger pieces of grit or pebbles cemented together.
  3. Igneous rocks contain crystals that point in many directions; metamorphic rocks contain crystals that mostly line up.
  4. Rocks that contain interlocking grains or interlocking crystals are non-porous; rocks that don't are porous.
  5. The properties of rock influence their uses.

Common misconception

Pupils sometimes focus on one feature to classify rocks as one type or another.

Stress that the rock classification system is gradual - show examples of various metamorphic rocks, highlighting similarities / differences.

Keywords

  • Sedimentary - A type of rock formed from the compression of sediments (rock fragments, minerals and remains of dead plants and animals).

  • Metamorphic - A type of rock that has changed due to heat and/or pressure (e.g. marble, slate).

  • Igneous - A type of rock formed from magma, either erupted from a volcano (e.g. pumice) or cooled below ground (e.g. granite).

  • Porous - A rock with spaces between the grains.

  • Non-porous - A rock with no spaces between the grains or one that contains interlocking crystals.

Use commonly used (and more easily categorised) rock samples to start, then introduce more difficult ones as the topic progresses.
Teacher tip

Equipment

Sedimentary: limestone (sample with a fossil / shell), sandstone and conglomerate (sample with larger pebbles); metamorphic: marble, gneiss; igneous: granite, basalt and pumice; examination hand lens.

Content guidance

  • Risk assessment required - equipment

Supervision

Adult supervision required

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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6 Questions

Q1.
What is a mineral?
A type of rock made of organic matter.
Correct answer: A naturally occurring pure substance with a crystal structure.
A synthetic compound used in construction.
A rock fragment found in soil.
Q2.
Which of the following properties are not typically used to identify minerals?
hardness
colour
Correct answer: smell
density
Q3.
Which of the following materials is known for its hardness and is often used in jewellery?
talc
Correct answer: diamond
limestone
granite
Q4.
Which of the following physical properties describes how easily a material can be scratched?
density
Correct answer: hardness
transparency
malleability
Q5.
A is a solid mixture of minerals or organic matter.
Correct Answer: rock
Q6.
The of a material describes its mass per unit volume.
Correct Answer: density

6 Questions

Q1.
Which of the following is a characteristic feature of sedimentary rocks?
interlocking crystals
Correct answer: grains stuck together
non–porous
formed from magma
Q2.
Which of the following distinguishes igneous rocks from other rock types?
The presence of fossils.
Correct answer: Composed of crystals that point in many directions.
Composed of compressed sediments.
Formed due to heat and pressure.
Q3.
Which of the following statements about metamorphic rocks is incorrect?
They contain aligned crystals.
Correct answer: They form from compressed sediments.
They are non-porous.
They form due to heat and/or pressure.
Q4.
The properties of igneous and metamorphic rocks make them suitable for a variety of purposes. Which of the following are not typical uses?
building materials
sculptures and monuments
Correct answer: car parts
Correct answer: food containers
kitchen worksurfaces
Q5.
Which of the following types of rock is marble?
sedimentary
igneous
Correct answer: metamorphic
Q6.
rocks have spaces between the grains or crystals, allowing water to pass through.
Correct Answer: porous