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Year 9

Formation of sedimentary rock

I can describe the formation of sedimentary rock and suggest information that can be obtained from its layers.

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New
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Year 9

Formation of sedimentary rock

I can describe the formation of sedimentary rock and suggest information that can be obtained from its layers.

Download all resources
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Share activities with pupils
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Lesson details

Key learning points

  1. Water in nature always contains minerals.
  2. Sediments are deposited when wind or waterways slow down or when glaciers melt.
  3. Layers of sediment form over many years, leading to compaction.
  4. Sedimentary rock forms when sediment is buried and compressed, and salts from fluids cement the grains together.
  5. Strata can be used to create a relative timeline and provide clues to the environment when the sediments were deposited.

Keywords

  • Sediment - a material deposited by water, wind or ice, such as pebbles, sand, or salts left by evaporation

  • Deposition - the process of sediment grains settling out (i.e. being deposited) from water or wind as their flow slows, or as ice melts

  • Compaction - a process where sediment grains become compacted (i.e. squashed closer together) during burial

  • Cementation - a process by which sediment grains are cemented (i.e. stuck together) by minerals deposited from groundwater, turning the sediment into rock

  • Strata - layers of rock (i.e. several rock beds) formed by the deposition of sediment

Common misconception

Some pupils think that compaction and cementation are the same processes.

Highlight that compaction is due to pressure while cementation occurs when minerals act as a 'glue' holding sediments together.

Create two mixtures - one of sand and water, the other of sand, water and cement. Use two large gauge plastic syringes to form two 'worms' - one of each mixture. Leave the 'worms' to dry and compare the results. Both have been compacted, but only one is cemented.
Teacher tip

Equipment

For teacher tip: 2× large gauge plastic syringes, 2× disposable cups (to use as mixing bowls), sand, water, cement, stirring rod.

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).

Lesson video

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Starter quiz

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6 Questions

Q1.
Match the keyword to the correct statement.
Correct Answer:Weathering,Wearing down or breaking of rocks while they are in place.

Wearing down or breaking of rocks while they are in place.

Correct Answer:Expansion,An increase in volume which occurs as liquid water freezes.

An increase in volume which occurs as liquid water freezes.

Correct Answer:Freeze-thaw,Physical weathering process.

Physical weathering process.

Correct Answer:Erosion, Removal of rock fragments to a new location.

Removal of rock fragments to a new location.

Q2.
Landslides are an example of erosion.
Correct Answer: gravitational
Q3.
When fragments of rock hit each other, and as they travel down a river or in the sea, more bits may break off. What is the name of this process?
Correct answer: Erosion
Weathering
Freeze-thaw
Melting
Q4.
Shells are made of calcium carbonate. What would be formed if fragments of shell were added to vinegar?
A blue solution.
Correct answer: Release of carbon dioxide gas.
Release of hydrogen gas.
The shell fragments would not react with vinegar.
Q5.
Choose the best description of a fossil.
Something very old.
Correct answer: Preserved remains or traces of a dead animal or plant more than 10 000 years old
Soft body parts of a dead animal found inside a rock.
Bones of a dead animal.
Q6.
Which rocks are types of igneous rock?
Correct answer: Basalt
Correct answer: Granite
Sandstone
Marble

Exit quiz

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6 Questions

Q1.
What is sediment?
A type of rock formed from lava
Correct answer: A material deposited by water, wind, or ice, such as pebbles, sand, or salts
A type of mineral found only in caves
A process where rock layers are formed
Q2.
What is the main cause of sediment deposition?
Increase in temperature
Correct answer: Slowdown of wind or water flow, or melting of ice
Increase in wind speed
Earthquakes
Q3.
Put the following steps of sedimentary rock formation in the correct order. This sequence should represent the journey from loose sediments to solid rock.
1 - Sediments are transported by wind or water
2 - Deposition of sediments
3 - Compaction
4 - Cementation
Q4.
What are strata in sedimentary rocks?
Minerals that cement sediment grains
Correct answer: Layers of rock formed by sediment deposition
Types of sedimentary rocks
Processes that transport sediments
Q5.
occurs due to pressure, squashing sediment grains closer together during burial.
Correct Answer: compaction
Q6.
Strata can be used to create a relative timeline because each layer represents a period when were deposited. The deeper layers are older, and the higher layers are younger.
Correct Answer: sediments