6th grade · Science · Unit 5 of 10
The Rock Cycle
Igneous, sedimentary and metamorphic
What your child practices
How igneous, sedimentary and metamorphic rocks form and change into one another, weathering and erosion, and a short reading passage.
Alabama Course of Study content standard: 6.5 · constructive and destructive processes that form and change rock
How we explain it
Children can open this short lesson before they practice.
- Igneous rock forms when magma or lava cools.
- Sedimentary rock forms when pieces from weathering and erosion settle in layers and press together.
- Metamorphic rock forms when heat and pressure change a rock.
- The rock cycle has no start: any rock can become any other type.
Example: Lava from a volcano cools and hardens. Which kind of rock forms? Lava is melted rock. Rock that forms from cooled melted rock is igneous. Answer: igneous
The Rock Cycle in Alabama
In the Alabama Course of Study, this is unit 5 of 10 in 6th grade Science, after Stars & the Universe and before Managing Resources.
Gradelings describes a child's practice on this unit as Beginning, Approaching, Meeting or Exceeding (Four practice steps). That reflects practice, not a report-card mark: the teacher decides the mark.
Sample questions
A taste of this unit. In the app, questions change every time and get easier or harder to match your child.
Question 1
Put the steps that make sedimentary rock in order.
- 🟫The sediment settles in layers
- 🌧️Weathering breaks rock into small pieces
- 🪨Layers are pressed and cemented into rock
- 🌊Erosion carries the pieces away
Weathering breaks rock into small pieces → Erosion carries the pieces away → The sediment settles in layers → Layers are pressed and cemented into rock
Hint: First rock breaks down (weathering), then the pieces are moved (erosion), dropped in layers (deposition), and finally pressed and cemented together.
Question 2
What is the difference between magma and lava?
🌋- magma is cool; lava is hot
- magma is underground; lava has reached the surface
- they are made of different materials
- magma is solid; lava is liquid
magma is underground; lava has reached the surface
Hint: Both are melted rock. It's called magma below ground and lava once it erupts out.
Question 3
Igneous, sedimentary or metamorphic? Tap a rock, then tap its basket.
Sort into: 🌋 igneous · 🟫 sedimentary · 🔥 metamorphic
- ⚫basalt
- 🪞obsidian
- ⬜marble
- 💎quartzite
- 🐚limestone
- 🪨conglomerate
🌋 igneous: basalt, obsidian · 🟫 sedimentary: limestone, conglomerate · 🔥 metamorphic: marble, quartzite
Hint: Igneous rock forms from cooled magma or lava. Sedimentary rock forms from pressed layers. Metamorphic rock is changed by heat and pressure.
Question 4
How does metamorphic rock form?
- wind wears rocks down
- lava cools on the surface
- heat and pressure change rock that already exists
- sand settles in a lake
heat and pressure change rock that already exists
Hint: 'Metamorphic' means 'changed form.' Deep underground, heat and pressure change rock without fully melting it.
Question 5
A metamorphic rock is pushed deep underground and melts. What happens next in the rock cycle?
- it can never change again
- it turns into a fossil
- it becomes sedimentary rock right away
- it becomes magma, which can cool into igneous rock
it becomes magma, which can cool into igneous rock
Hint: Any rock that melts becomes magma. When magma cools, it forms igneous rock.
Question 6
How does sedimentary rock form?
🟫- magma cools underground
- heat and pressure change rock without melting it
- lava cools quickly
- layers of sediment are pressed and cemented together
layers of sediment are pressed and cemented together
Hint: Sediment is bits of sand, mud, pebbles and shells. Over time, layers of it harden into rock.