Monday, 15 February 2016

The questions to ask about sedimentary grains

Today's new Earthlearningidea continues our field work series with 'Questions to ask at any rock face 5: sedimentary grains'. 

Ask your pupils to answer the following questions when they are looking at any natural rock face - in a cliff, a quarry or a building.
- How big is the largest grain you can see? (estimate the length in mm or cm)
- When the sedimentary grains were being laid down, how might they have been moved here – by wind, water, ice or gravity?
- Was this deposit laid down in low, medium or high energy conditions? (More energy is needed to move and deposit large grains than smaller ones)
- Does the rock have several sizes of grains or just one size? (The further grains are carried, the more they tend to be sorted out into coarse, medium and fine sizes)
- Have these grains travelled far? (Grains with sharp corners have not moved far but rounded pebbles will have travelled a long way)
- What does the grain evidence tell you about this sedimentary deposit?
Lots more ideas for teaching about sedimentary rocks or fieldwork can be found on the website.

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