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Pigments from soil
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Objectives
- To learn about and use grinding and sieving
methods to produce pigments from collected natural materials.
- To produce a 'cave painting' using paints
made from their own pigments.
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Curriculum links
English National Curriculum:
Art: 1c, 2a, 4b, 5b
Design & Technology: 2a, 3a, 4b
| Gateway story
The series of images represents the grinding and use of natural
pigments to create 'cave paintings', which the children do in this
activity.
Gateway elements
The gateway consists of:
- Pestle and mortar
- Children painting
- Children's cave painting.
Pestle and mortar: The pestle is the 'grinder' and the mortar
is the bowl. These are usually ceramic, and are used to grind lumps
of soil and other natural materials into a fine powder. This powder
can then be used as a pigment.
Gateway discussion
Whilst looking at the gateway, ask the children some of the following
questions:
- What are the children doing?
- What kind of painting have they created?
- What does the top right picture show?
What is this used for?
- What link might there be between the
cave painting and the pestle and mortar?
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Approximate time required:
2 hours
Resources needed
250 g (approx.) of each locally collected soil
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Sand and sandstone in as many shades and colours as possible
Pestle and mortar (if possible)
3-4 rolling pins
1-2 small hammers
3-4 tins or plastic jars with lids
Pebbles (enough to half fill each of the above tins)7-8 colanders and
sieves
Plastic bags (tough, transparent)
Water
PVA glue or paste
Safety goggles
Reproductions of cave paintings, found in books and other resources
A1 or A2 size paper or board
Suggested organisation
Groups of 3- 4 children.
Carrying out the activity
Each group is given the material they are going
to work on and is told to consider what they need to do to turn it into
a finely powdered pigment. Discuss the choice of methods of grinding and
the appropriate use of each one on the materials available.
Questions can include:
How can you turn the material into a fine powder?
- What tools
could you use to do the job?
- Will everyone
in the group have a 'job' if you plan the task first?
- How will you
know when the powder is fine enough?
- How can you
remove the larger pieces that you don't want?
- Can the large
pieces still be used?
The children or the teacher may decide which
grinding equipment each group will use.
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SAFETY NOTE
The breaking of sandstone
should be done under adult supervision. Anyone involved must wear
safety glasses.
The stone is placed inside a strong plastic bag on a hard surface
away from other pupils. The bag must be fastened securely before
hammering commences.
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The children can be given the following hints:
- allow the pigment material to dry out thoroughly
before grinding
- work on small amounts of around 50g at a
time
- pick out small stones by hand
- more grinding and re-sieving may produce
more powder
- mixing in a small amount of PVA glue will
help to bind the grittiness of the pigment.
Each group carries out the grinding and sieving
to their satisfaction (comparison with school powder paint may be a good
guide). They may discard large lumps, or choose to re-grind them.
The children then mix their pigment gradually
with water, the binding medium, to produce a usable paint. Adding a little
glue or paste as well may improve the 'flow' quality of their paint. They
might decide to add some glue to a test portion of their paint, before
combining it with their entire sample.
Each group will produce a different quality of paint, both in colour and
texture. Samples of the results should be labelled, displayed and discussed
to share techniques and ideas.
The groups now use the paints to produce a 'cave painting' or on another
project that makes use of muted natural colours. If each group have produced
sufficient, the samples can be shared, in order to provide each group
with a range of colours.
Background information
The cave paintings of Lascaux in France were
made 30,000 years ago and provide some of the clearest examples of the
use of natural pigments by ancient people. We can only guess at the reasons
for making these powerful images deep in dark caves. They were probably
not made as decoration, but either as some kind of religious or magical
protection or as a means of charming their prey into submission.
Mineral pigments are still used in many modern
paints, though advanced technology has changed and improved them and many
can be reproduced synthetically. Examining the names of artist's paints
shows that soils are a basis of many colours, e.g. burnt umber and raw
sienna. Other sources of colour names can easily be identified, for example;
flowers, place names, people, fruit, jewels, birds and animals.
Extensions / links
ICT
The children can use the forum
to communicate with classes elsewhere in the country who have already
done this activity, or would like to work on it. They can exchange ideas
and arrange to exchange soils and sand samples that might produce other
colours and textures.
Art
Further experiments can be carried out by adding
other materials to the paint to change its texture. These can then be
used for art projects on a larger scale, possibly examining local examples
on the exteriors of buildings as a starting point.
Design & Technology
Use the idea of an exterior decoration on a school
wall as an incentive for children to design a mural. It may even be turned
into a reality.
Science
Children can find out more about grinding solid
materials in the Grinding Chalk activity.
English
The children are challenged to make a collection
of as many colour names as they can that come from nature, e.g. flowers,
soils, animals (see Background Information)
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