How Rocks Change Over Time

Science · Volcanoes & Earthquakes · ages 9-11

Name ______________________ Date ____________

True or false: once a rock becomes metamorphic, the rock cycle is finished for it.
Circle one: True False
Which sentence best describes the rock cycle?
- It is a one-way trip that stops once rock becomes metamorphic
- It is a loop where rock keeps changing type, with no true start or end
- It only happens when a volcano erupts
Wind and rain slowly break igneous rock into tiny pieces. What does igneous rock become at this first step of the cycle?
- Sediment
- Lava
- Metamorphic rock
A layer of sandstone gets buried deep underground, where heat and pressure squeeze it but it does not melt. What does it become?
- Metamorphic rock
- Igneous rock
- Sediment
Sediment piles up in layers and gets pressed together for a long time. What does it become?
- Sedimentary rock
- Metamorphic rock
- Magma
About how long does it usually take for rock to move through the whole rock cycle?
- A few days
- A few years
- Millions of years
Jamal says marble forms the instant hot lava cools and hardens. What is wrong with his idea?
- Marble is metamorphic rock. It forms when heat and pressure change limestone underground, not from cooling lava
- Marble cannot form from any other rock
- Marble only forms inside volcanoes
Which path correctly follows one full trip through the rock cycle?
- Igneous rock, then sediment, then sedimentary rock, then metamorphic rock, then melts into new igneous rock
- Metamorphic rock, then igneous rock, then sediment, then melts
- Sedimentary rock, then sediment, then igneous rock, then metamorphic rock, then sediment

Answer key

For grown-ups. Fold this page away before handing over the rest.

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False · Metamorphic rock can still melt or be worn away by weathering, so the cycle keeps going.
It is a loop where rock keeps changing type, with no true start or end · The rock cycle never really stops. Rock keeps moving between igneous, sedimentary, and metamorphic forms.
Sediment · Weathering breaks rock into small pieces called sediment. That sediment can later become sedimentary rock.
Metamorphic rock · Heat and pressure without melting change sedimentary rock into metamorphic rock, like marble or quartzite.
Sedimentary rock · Pressed and cemented layers of sediment form sedimentary rock, like sandstone.
Millions of years · The rock cycle runs on weathering, pressure, heat, and melting, all of which work extremely slowly over millions of years.
Marble is metamorphic rock. It forms when heat and pressure change limestone underground, not from cooling lava · Cooling lava makes igneous rock. Marble is metamorphic rock, made when heat and pressure change limestone without melting it.
Igneous rock, then sediment, then sedimentary rock, then metamorphic rock, then melts into new igneous rock · That path follows weathering into sedimentary rock, then heat and pressure into metamorphic rock, then melting back into igneous rock.