Soil Desert: Living and Non-Living – the making of soil.
Adapted from Agrium http://www.growingthenextgeneration.com/just-for-kids.html
Science understandings:
 A healthy soil is made up of a mixture of non living and living material.
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A good soil will have all 3 types of non living particles in it – Sand, silt and clay.
Sand comes from rock. Silt are even smaller particles of sand. Clay particles are so
tiny you cannot see them with the human eye.
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Living material is made up of living and once lived plant and animal material.
Rotting plants (and animals) are mostly dark brown in colour and are the food for the
soil animals.
Worms create channels in the soil for water and air and mixing up the soil when they
make the channels.
Worm poo is the waste from the worms – created by eating what is in the ground.
That is mostly rotted plant material.
There are millions of micro organisms in the soil – even in 1 tablespoon of soil. They
help break down things that were once alive so the plants can get the goodness out
of it.
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Resources:
For the non-living particles:
Bowls with
cream cheese cinnamon mix - clay
cocoa powder - silt
brown sugar - sand
Spoons for mixing
Bowls for mixing
Hand washing / drying stuff
For the living particles:
Bowls with
gummy worms/snakes - worms
coloured sprinkles - micro organisms
pretzel sticks – rotting plant material
raisins – worm poo
Method:
1. Wash your hands carefully before you start this experiment.
2. Teacher model first. Tell the story of how a soil is made – mixing in a bowl each
ingredient starting with the soil particles. Then add in the rotted material, worms and
and poos and sprinkle the top with micro organisms.
3. Ask the students to observe and identify each of the non-living particles - noting
what each sample feels like or sounds like when they rub it between their fingers.
4. Tick the boxes that match what they think for each sample. Put the sample in their own
bowls to mix up their desert.
5. Follow the ticks to find out what each sample represents - Clay, Silt or Sand.
When you look at
the size of each
particle …
I am the largest
particle.
I am the mid sized
particle.
I feel …
loose, gritty and
rough like
sandpaper.
smooth and silky.
When you rub me
together …
I will make a raspy
sound.
I will make a
squeaky sound.
I will make no
sound.
When you try to
make me into a
small ball …
I will not stick
together.
I will only stick
together when I am
wet.
I will roll into a ball
easily. I will stick
together.
I am …
Sand
Silt
I am the
smallest. You
will need a
microscope to
see me.
smooth and sticky
like glue.
Clay
6. Add in the rotting plant material. It is no good to plants living in soil yet.
7. Add in the worms – remembering what they do - that they turn rotting plants and dead
animals into poo.
8. Add in the poo – the worms have produced – reinforcing that the plants can now use
this fertilizer - as the plants can access all the goodness in the rotted material.
9. Sprinkle on the micro organisms – they help the plant access the goodness from the
worm poo and other such jobs.
10. Fill in the table to remind you who does what and whether I am alive or was alive once.
11. Mix it all up and taste sample your healthy dirt.
I am a …
I am create channels in the soil
for water and air. I mix the soil
particles up when I make the
channels.
I once was food that animals
ate but now I am waste. I am
mostly plant material.
I am mostly dark brown in
colour. I am food for the soil
animals.
There is lots of us, millions of
us in a table spoon of soil. We
help break down things that
were once alive.
Am I still alive or I was I
once alive?