LESSON 1

Rocks are different.

This lesson sets the scene for the rest of the topic and can be returned to at the very end.

Rocks are not just rocks, they vary in a huge number of ways which depends on how they were formed.

Using a large  sample of rocks, students look at a each one carefully and try to establish some of the following:

hard or soft?

grains or crystals (size?)

colour?

fossils in the rocks or not?

react with acid?

Layers or not?

Porous or not – put in water and look for bubbles

LESSON 2

WEATHERING

Chemical

Physical

that rocks at the Earth’s surface disintegrate through exposure to water in the environment, which causes chemical reactions

that rocks are broken down by forces that result from stresses generated when water in cracks and fissures expands on freezing. FREEZE-THAW

that rocks at the Earth’s surface are broken down by forces that result from stresses generated when rocks expand and contract on heating and cooling

React marble with acid to show that some rocks react. Could weigh marble before and after to show that there is less rock after.  Nice chance to revise test for carbon dioxide if gas is bubbled through limewater.  More able should realise that there are carbonates in the marble (will return to this later).

Granite is a very hard rock and does not react with acid.  Use granite with large crystals. Hit with hammer – will not break.  Heat in very hot Bunsen flame, then “dunk”  in cold water immediately.  Repeat several times.  Granite will then shatter very easily.

Any demonstration that water expands when frozen then a series of diagrams needed to show what happens when cracks in rocks fill with water and then freeze.

LESSON 3

EROSION

that rock fragments become sediment grains which can be transported by water currents and deposited when the energy is dissipated

that as transportation times and distances increase, sediment grains become more rounded

Use v. large plastic measuring cylinder with a bung in the top.  Each group needs at least 10 plaster “ice cubes”.  Weigh, measure and draw a “cube” before start.  Put all cubes in measuring cylinder and shake for 30 seconds. Take one (or more and find mean) out, weigh, measure and draw.  Repeat for another 4 or 5 30s shakes.  Could try this with and without water in tube – make sure top is properly sealed if using water!

LESSON 4

TRANSPORTATION and DEPOSITION

that larger grains are not taken as far, as it requires more energy to move them

that sediment grains of similar size are deposited together

that sedimentary layers are the result of distinct episodes of sedimentation over a variety of timescales

Use a halved drain pipe and put a sand,  gravel  mix at the top.  Tilt and send water down trough gravel for a while.  Note which grains finish where. 

Mix a jar of clay, sand, gravel etc with lots of grain sizes.  Give it a good mix up and watch the order of deposition.  Draw layers in next lesson.

LESSON 5

SEDIMENTATION

that sedimentary layers can be formed by the evaporation of waters containing dissolved salts

that the remains of dead organisms and their shelly material can accumulate to form sediments

to use evidence in rock layers to suggest a sequence of events over time

about the use of fossils as evidence

Use the rubbish bin analogy.  From packaging put in bin, work out what happened in a household over a week.  The lower down in the bin the rubbish is, the earlier in the week the event happened.

Show Grand Canyon video from Website.