Rocks D. Crowley, 2008

Rocks To be able to sort rocks by their appearance and properties

Rock Grouping There are many different types of rock… What is a rock? How do they vary? How can we group them? Look at the following selection of rocks – using the table see if you can group them

Rock Properties Tick the box if the rock contains the property. Note any extra information in the other column RockLayers?Crystals?Grainy?Heavy?Bubble in water? Fossils?Other Sandstone Slate Limestone Basalt Schist Granite

Rock Appearance A rock is made of grains that fit together Each grain in the rock is made from a mineral, which is a chemical compound The grains in a rock can be different colours, shapes and sizes – this is what gives them different textures

Rock Texture In some rocks the grains fit together and there are no gaps Their grains are interlocking and these rocks are sometimes called crystals Interlocking grains, such as granite

Rock Texture In other rocks the grains are rounded, and do not fit together (there are lots of gaps) Their grains are non-interlocking Non-interlocking grains, such as sandstone

Porous Rocks with rounded grains are more likely to absorb water than rocks with interlocking grains because the water can get into the gaps between the grains Rocks that absorb water are called porous Rocks with rounded grains are usually softer and more crumbly than rocks with interlocking grains

Explanation Can you explain why sandstone is lighter than some other rocks? Why does it sometimes release bubbles when submerged in water? Sandstone is lighter than some other rocks as it has non-interlocking grains – this means there are lots of gaps (and the rock’s density is lowered) The gaps can often contain pockets of air, which release bubbles when submerged

Rock Texture

Rock Model