7.1 Earth structure

A mineral is:

• another name for a rock.

• a chemical compound found in rocks.

• a hard piece of material.

• a type of salt.

In science, the texture of a rock is:

• the way it feels.

• whether it is hard or crumbly.

• its colour.

• the size and shape of the grains.

Which statement describes this rock?

• rounded grains of three different minerals

• interlocking grains of two different minerals

• interlocking crystals of three different minerals

• rounded grains with gaps between them

Some rocks are permeable because:

• the rock dissolves in water.

• water can get into gaps between the grains.

• animals have dug burrows in the rock.

• the rock is made of interlocking crystals.

Igneous rocks are formed when:

• magma or lava is put under pressure.

• magma or lava cools down.

• magma or lava is heated up.

• magma or lava evaporates.

When an igneous rock is forming:

• large crystals will form if the magma heats up quickly.

• small crystals will form if the magma cools slowly.

• large crystals will form if the magma cools slowly.

• small crystals will form if the magma evaporates quickly.

According to the particle theory, large crystals will form if:

• lots of particles have time to bond together into a regular pattern before the liquid cools.

• the particles are kept as far apart as possible.

• the particles have time to collect together before they melt.

• the particles cool quickly and don’t have time to move apart.

Metamorphic rocks are formed by the effects of:

• high pressures or low temperatures.

• high pressures or high temperatures.

• low pressures or high temperatures.

• low pressures or low temperatures.

Physical weathering happens to rocks when:

• the weather is always hot.

• the weather keeps changing between hot and cold.

• the weather is always cold.

• the rock gets struck by lightning.

Freeze–thaw action damages rocks because:

• the rocks melt.

• the rocks freeze.

• water expands when it thaws.

• water expands when it freezes.