How igneous, sedimentary and metamorphic rocks form and change into one another, weathering and erosion, and a short reading passage.
Minnesota K-12 Academic Standards benchmark: 6E.3.1.1.2 · how Earth's rock materials cycle
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 Minnesota
In the Minnesota K-12 Academic Standards, this is unit 2 of 7 in 6th grade Science, after Our Solar System and before Plate Tectonics.
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.
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.
🌧️Weathering breaks rock into small pieces
🟫The sediment settles in layers
🌊Erosion carries the pieces away
🪨Layers are pressed and cemented into rock
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
Which kind of rock is most likely to contain fossils?
🐚
igneous
metamorphic
sedimentary
sedimentary
Hint: Plants and animals can be buried in layers of mud or sand that slowly become sedimentary rock.
Question 3
Why did the granite have large crystals?
A Pebble's Long Trip
Long ago, magma deep under a mountain cooled very slowly and hardened into granite. Because it cooled so slowly, its crystals had time to grow large enough to see.
Over millions of years, the mountain wore down and the granite reached the surface. Each winter, water froze in its cracks and split off small pieces. A river carried the pieces downstream, tumbling them until they were smooth pebbles and grains of sand.
Where the river met a lake, the sand settled in layers on the bottom. More layers piled on top. Over a very long time, the weight pressed the layers together, and minerals in the water cemented the grains into sandstone.
it cooled quickly in the air
it was tumbled by the river
it was cemented by minerals
it cooled slowly deep underground
it cooled slowly deep underground
Hint: The first paragraph explains it: slow cooling gives crystals time to grow.
Question 4
Granite is an igneous rock with large crystals. How did it form?
🪨
lava cooled in seconds in the air
magma cooled slowly underground
mud was pressed into layers
limestone was heated and squeezed
magma cooled slowly underground
Hint: Slow cooling underground gives crystals time to grow big.
Question 5
Does the rock cycle have one starting point?
🔄
yes, it always starts with sedimentary rock
no, any type of rock can change into another type
yes, it always starts with metamorphic rock
no, any type of rock can change into another type
Hint: It's a cycle, like a circle. Igneous, sedimentary and metamorphic rocks can each change into the others.
Question 6
Igneous, sedimentary or metamorphic? Tap a rock, then tap its basket.