Download Rocks and Soils - Growing Schools

Meanwood Valley Urban Farm
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ROCKS
Take the children on a walk round the Farm and show them the different types
of rock found on the Farm and explain what we use it for. The children will
have to remember the info for later
LIMESTONE – ON THE PATH LEADING TO THE SHEEP
You find limestone in the Yorkshire Dales in places such as Malham Cove.
Limestone is used in hardcore, which builders lay down before they build
a road or a building to stop the ground sinking and causing subsidence.
Limestone can be carved to make statues and sculptures such as the lions
outside Leeds Town Hall. If you look carefully at them you will notice they
have been eroded by Leeds’ acid rain
GRANITE – THE SPECKLY STONE ON THE PATH TO THE FARM YARD
Granite is a very hard rock which is formed from molten rock below the
earth’s crust. It is pushed above the surface by movement of tectonic
plates (volcanoes, earthquakes etc.) In the olden days it was used for
kerb and cobblestones, because it could resist a lot of wear and tear.
Because it is so hard, it can be worked to a high polish. Granite can be
seen covering important buildings such as banks, and is used as work tops
for some kitchens.
SLATE – ON THE FARMHOUSE ROOF
Slate is formed from mud that has been compacted over thousands of
years. As the tiny mud particles are squashed, they line up in the same
directed and become “laminated”, which means that they are in layers.
These layers mean that the rock can be broken up into thin waterproof
slabs, which are ideal for tiling roofs. Slate is expensive, though, and in
recent years people use concrete tiles on their roofs as a cheaper
alternative.
MILLSTONE GRIT – REED BED WALL
Millstone Grit is a local stone formed by the deposition of sand in ancient
river deltas, and over the years it becomes squashed and hard. In the
olden days, it was used for millstones (hence its name) and you can see
some of these millstones in the beck in Meanwood Park. Because it is a
local stone, many old buildings and walls in Leeds are made from it. You
can see this stone in the wild on Ilkley Moor.
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Testing Rocks
You will need
Granite, Slate, Limestone, Millstone Grit
Magnifying Glasses
Glass
HCl
Worksheets and Answersheet
Children should be in four groups. Start with one rock and carry out all the
tests on the worksheet. Match the rock up with the answersheet and see if they
can remember what the rock is used for. Continue with the rest of the rocks,
until they have worked out which rock is which and what it’s used for.
Encourage the children to look at the rocks with the magnifying glasses and
observe their structure.
The slides for the microscope were kindly donated by Leeds University.
Inside them there are slices of rock that are so thin that the light shines
through them.
LIMESTONE
Made from compressed fossilised sea creatures. You may be able to see
the tiny fossils of the creatures in the slide.
GRANITE
You can see all the different minerals that crystallise to make up granite.
These crystals are formed when the molten rock cools down
MILLSTONE GRIT
Made from round particles. The movement of the water in the ancient
river delta where this rock was formed has worn down the particles of
sand until they are rounded and smooth. You can see these round particles
in the slide.
We haven’t got any slate as the particles are so flattened that they don’t
let any light through
Soils/ Mud workshop
You will need
Bucket of Sand
Bucket for Soil
Scoops or trowels
Soil bags
Several plastic bottles for wormeries
Plain sheets of Paper
Beakers
Meanwood Valley Urban Farm
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Stirrers
Intro
Explain rules of Farm
 No Running
 Fingers out of noses and mouths
 No eating till lunch
 Wash hands after project
 Shut gates
What are we going to find out about today?
Soil!
Hand out bags one between two and go to an area of garden with bare soil.
Get the children to take a handful of soil and see if they can guess what the
ingredients are.
What can they see and feel in the soil?
Animals, bits of plant (organic matter), stones and sand, water.
So know we know the ingredients of soil we can make our own!
Get the children to fill their bags with plant material, stones and water (no
animals though). Get them to jump on their bags to mush the ingredients up.
Does it look like soil?
No
Why not?
The missing ingredient is time. The dead plants and animals can take months to rot down
become part of the soil, but it has take thousands of years for the tiny bits of stone in the
soil to appear. Once they may have been part of a cliffside, and the action that turns a
cliffside into sand is called weathering. Here are some of the main types:
Wind.
In sandy places such as deserts the wind can pick up the sand and blast it against rock.
This acts like sandpaper and wears the rock down. The pyramids in Egypt have been
weathered in this way
Rain
Acid rain dissolves some rocks, especially near towns and cities. If you take a look at the
lions outside Leeds town hall, you will notice that they look very worn. This is because
the acid rain in Leeds has dissolved them
Ice
If you put a plastic bottle full of water with the lid screwed on tight, and put it in the
freezer over night, in the morning you will find a broken bottle full of ice. This is because
when water freezes it expands. So when it rains on a cold winter’s day, and the water
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trickles into cracks in the rocks, in the night time when the temperature falls below zero
the water will turn to ice, expand and make the crack bigger.
Rivers and Seas
Flowing action by rivers and wave action by the sea bashes sand and stones together and
wears them down. You can tell rocks that have been affected in this way as they are
usually round.
Take the children to have a look at the sand and silt left in the water meadow
by the Beck then go back in the Epicentre
Put beakers on each table and fill them will a bit of soil and water, Get the
children to give the beaker a good stir and then leave in the middle of the
table. Get them to draw the outline of a beaker on half a sheet of A4 and help
then to draw the layers of soil as they settle out
From the bottom the layers they should have are:
-Gravel
-Sand
-Silt
-Clay
At Top
-Organic Matter
-Air bubbles
Get them to stick the corresponding substrate on their sheets with cellotape
Wormery
Worms are very good for the soil as they mix up organic matter in it and
aerate it. We are going to make a wormery for you to take back to school
that will help you to see the way the worms move and eat.
Make wormery and go on a hunt for worms with the kids. Take a few
leaves for the worms to eat.