How rocks change from one kind to another

Grade 6 Science Worksheet

Circle the best answer.

1. 1.

   Bo compares two igneous rocks. Granite has large crystals; basalt has tiny ones. Which one cooled slowly, deep underground?

   • Granite, because pressure squeezed its crystals big
   • Granite, because slow cooling grows large crystals
   • Basalt, because slow cooling makes tiny crystals
   • Basalt, because darker rock cools more slowly
2. 2.

   Obsidian looks like smooth black glass, with no crystals Esme can see. What does that show about how it formed?

   • Layers of sand were pressed together
   • Heat and pressure changed it without melting
   • Lava cooled so fast that crystals could not grow
   • It cooled very slowly, deep underground
3. 3.

   Jun drops a light, bubbly rock called pumice into water, and it floats. It formed from frothy lava that cooled very quickly. What are its crystals like?

   • Large, because gas holes make room to grow
   • Tiny or none, because it cooled fast
   • Lined up in layers, like sedimentary rock
   • Large, because it cooled fast
4. 4.

   A metamorphic rock deep underground gets so hot that it melts, then cools again. What does Milo say it becomes?

   • A sedimentary rock
   • Nothing; metamorphic rock is the last step
   • An igneous rock
   • A new metamorphic rock
5. 5.

   Noah finds a rock with flat layers and a leaf fossil pressed between them. Which clue points to sedimentary rock?

   • It must have melted to hold a leaf
   • It was squeezed into wavy bands
   • Its color is gray
   • Layers holding a fossil
6. 6.

   Pia sees a rock with light and dark minerals lined up in wavy bands that formed under great pressure. Which type of rock is it?

   • Lava rock full of gas holes
   • Igneous, because it melted into bands
   • Metamorphic, from heat and pressure
   • Sedimentary, because bands are sand layers
7. 7.

   Near an old volcano, Ren finds a dark rock full of small holes left by gas bubbles. Which story fits the clues?

   • Sand grains were pressed and cemented
   • Magma cooled slowly and grew big crystals
   • Heat and pressure squeezed it underground
   • Lava cooled fast at the surface, trapping gas
9. 8.

   Can a sedimentary rock become an igneous rock? Tala checks the rock-cycle diagram. Which answer is right?

   • Yes, if it melts into magma and then cools
   • Yes, if it is pressed and cemented again
   • No; it has to become metamorphic first
   • No; sedimentary rock just wears away
10. 9.

    A metamorphic rock is lifted up to the surface by moving rock. What could happen to it next, by Zee's diagram?

    Use the picture in question 8.

    • It must melt before it can change again
    • It turns straight into igneous rock in the air
    • It could weather into sediment and become sedimentary rock
    • It stays exactly the same at the surface
11. 10.

    “Rock-cycle diagram with an arrow from” Granite gets buried deep in a mountain range and is heated and squeezed, but it does not melt. What does Ari say it becomes?

    • Magma
    • Sedimentary rock
    • Metamorphic rock, such as gneiss
    • Nothing, since igneous rock cannot change