Do now!
Can you continue the questions on pages 84 and
85?
Last lesson
• Chemical and physical weathering
Chemical weatheringRain is slightly acidic as it contains substances dissolved from the air. It can react with rock, dissolving it.
Chemical weathering
Some rocks are dissolved more by acid rain than others
Limestone “pavement”
Physical weathering
Rocks can be weathered by physical changes
Physical weathering
When rocks are hot they expand, and when they cool they contract. Repeated changes cause the rock to crack, often causing rock to peel off.
Sometimes called “onion-skin weathering”
Physical weathering
Freeze-thaw weathering is another example
You now know all about freeze-thaw weathering
Today’s lesson
• Transport of weathered rock
• Soil
• Rock cycle
Transport
Rock falls to the bottom of rock faces and may be transported away by fast moving streams.
Abrasion
The rocks in the stream bed rub against each other and wear away. This is abrasion.
Sediment
The bits of rock in the stream bed are called sediment.
Deposit
Smaller rock fragments are carried further than large ones, eventually being deposited on the bottom in slow water.
Let’s try some questions!
Stick the sheet in and fill in the gaps.
You have 8 minutes!
What is soil?
A mixture of stones, smaller rock particles (sand) and humus (remains of dead plants and animals)
Copy?!
Can you copy the table on page 91?
The Rock Cycle
Can you read page 100 very carefully?
The Rock Cycle
Can you copy the diagram on page 100?