Rocks, fossils and soil

For grown-ups: this lesson in words

Years 3 to 6 · Science

Rocks, fossils and soil: I can group rocks by their properties, explain how a fossil forms, and say what soil is made of.

1. Rocks are not all the same. We can group them by what they are made of: crystals or grains.

   Granite and marble are made of crystals that fit tightly together, with no gaps. Crystals can sparkle.

   Sandstone and chalk are made of grains: tiny bits stuck together, with small gaps between them.

   Picture: Sorting into 2 groups: Crystals, Grains. Crystals: Granite (rock), Marble (rock). Grains: Sandstone (rock), Chalk (rock).

2. We can also group rocks by what happens when water drips onto them.

   Water soaks into chalk and sandstone. Rocks that let water soak in are permeable.

   Water stays on top of granite and slate. Rocks that do not let water in are impermeable.

   Picture: Sorting into 2 groups: Permeable, Impermeable. Permeable: Chalk (rock), Sandstone (rock). Impermeable: Granite (rock), Slate (rock).

3. Your turn: Ana drips water onto a rock. The water soaks into the rock. Is the rock permeable or impermeable?

   Choose one:

   • Permeable
   • Impermeable

   Answer

   The answer: Permeable

   The water soaked into the rock, so the rock is permeable.

Words to know

permeable, impermeable:

Permeable rocks let water soak in. Impermeable rocks keep the water on top.

crystals:

Pieces that fit tightly together, with no gaps. They can sparkle.

grains:

Tiny bits stuck together, with small gaps between them.

fossil:

The shape of a living thing from long ago, turned to rock.

organic matter:

Rotted bits of things that were once alive, like dead leaves.

loam:

Soil with a mix of big and small grains.