A few nails and a yard of wire
Keith Warren, Universidade Eduardo Mondlane, Mozambique
Teaching science in a laboratory without a laboratory - one academic, a
cameraman and a demonstrator with a few nails and a yard of wire show how in
Mozambique
One of the most pleasant parts of our work is to go to a village where we are
going to demonstrate science to children. We work very informally, usually where
we are known at least to the children who sometimes turn up and talk to us,
sitting on a log under a tree, ask us things and, as likely as not, give us more
information than we give them.
We like to arrive with nothing in our hands because we go to demonstrate with
local resources, and do not want to import any non-local things except
ourselves. And if we come up against a block where we have to have something
that absolutely does not exist in the village, it forces us to look for a
substitute. That was how we discovered how to use old chicken netting,
Talking with the children we occasionally refer to 'your laboratory' or 'our
laboratory', and when the children look puzzled and ask where it is or what we
mean, we ask one of them to stand there and extend her arm, point a finger out
horizontally and slowly turn around. "There it is," we say.
There is a general complaint in Southern Africa that we have no laboratories,
no science apparatus and no chemicals. But our group's speciality is to show
that this is the wrong way to look at it. People have become accustomed to see
problems and complain, even despair. But there is an alternative - to find
opportunities. The more you look, the more you find.
Magnets in the village
"Let's go and buy a battery," we say to the little group of
children. They are keen to help because they know they are going to see
something interesting. We wander with them to the market - two little stalls,
one with vegetables and fruit, and the other with common things like soap,
matches, batteries and so on, where we buy a common large-sized torch battery.
This turns out to be our only investment for the day.
Then we bargain for a three-inch nail. The stall-holder wants to sell us a
dozen but we settle for just two. "Go on, take them," he says,
"We know you are professors from the university, helping to teach our
children."
Well, they are one third right. I am the academic, Mateus is our cameraman
and Alberto our demonstrator. We call ourselves the 'Spark Group'.
"Throw in three of those other little nails," we say, and he does.
On the way we back to our tree we pass a piece of rather rusty chicken
netting. "Nationalise that," we say, and the children laugh and bring
it.
 Then comes the main part of our little drama. Two of the children undo some
of the chicken netting to get a yard of wire - fiddly work but not difficult -
and pull it back and forward to eliminate its wrinkles over an edge of the log
we are sitting on. The wire is a bit rusty but that will make no difference to
what we are going to do.
They wrap a bit of newspaper round the shank of the nail. That is the
insulation. Then wind the wire over the paper, making sure adjacent turns do not
touch. Then when the nail is full, another layer of paper and another winding of
wire. Then a third layer of paper and wire until the yard of it runs out. Then
some sewing thread wound over the end turns so they do not come undone.
Connect the ends of the wire to the battery and... we have an electromagnet
that picks up the little nails.
Everybody has a go. "Magic!" they say, delighted.
"No," we say gravely. "Science. Technology."
The next day several children will have made electromagnets at home and some
father will complain that his son has nationalised a battery from the family
radio and run it down.
Permanent magnets and a magnetic compass
Sometimes common nails are semi-steel and once magnetised will hold a little
magnetism. In this case the young experimenters see that one of the little nails
stays attracted when the battery is disconnected and understand that the
magnetic effect somehow stays in the electromagnet.
We ask the children to make another magnet but with the paper and wire not so
tight, so that after magnetising the nail they can pull it out. So they do this
and then of course they have a weak permanent magnet.
If the nails are not steel, we ask the children to try to get a piece of old
bicycle spoke or an umbrella rib, and bend it backwards and forwards until they
have broken a piece off. These are steel and the young people can usually find
one or the other in the village. If all else fails, they get a handful of
chicken netting and fold, hammer and twist it until they have a tight bundle.
This retains magnetism well.
Now they can make a magnetic compass.
They get a thread of fine plastic hair from a girl's plaits, tie it round the
middle of the nail, adjust it to hang horizontally, fix it with a bit of chewing
gum, and hang it up.
"It will point North and South," we say. But of course it does
nothing of the kind. As you can guess, it oscillates interminably and swings in
the wind.
So we cut a clear plastic bottle to make a cup, half-fill it with water and
hang the nail in the water from a pencil across the top. The water damps the
movement of the nail and it comes to rest North-South. A real working compass.
The children of course know where the sun rises and sets so they know roughly
where north is, and they take the nail out of the water, fix bits of paper
marked 'N' and 'S', on it with chewing gum, re-balance it, and put it back.
More classic physics
Then they make another weak permanent magnet so that with this and the
compass needle we can do the classic experiments of north attracting south,
repelling another north, seeing if the effect will go through paper or a
person's hand, and so on.
"Aha, yes!" they say - that exclamation every teacher likes because
it is the arrival of insight - "We learnt about this in the book but we
never understood it."
Well, now they will never forget it. In its small way it is dramatic, as all
science lessons should be.
They try other things. Will the magnet attract a coin? Yes, our Meticais are
cupro-nickel. Of course the weak magnet is far from being able to pick one up
but the children can detect the effect by seeing that the end of their compass
needle attracts itself to the coin, held near outside the plastic. One of my
brass Yale keys? No. The cut-off top of a Coke tin? No, it is aluminium. The
sides of the can? Yes, they are iron. And so on and so on. In the end, you can
tell that some of the children feel themselves to be real little scientists.
In a primary school, a laboratory is no more needed to teach appropriate
science than a language laboratory is needed in a home to teach a baby to talk.
How little we do
Notice that we visitors have done almost nothing physically in these
demonstrations; the children have done it all. But we have transmitted some
knowledge and confidence to a dozen of the younger generation through our
encouragement. Encouragement makes children blossom.
A dozen is not many, but we have a potentially powerful technique to multiply
the effect. Later Alberto, Mateus and I will come back with the video camera and
the children will do the experiments again and explain in their own way as they
do them. Such activities make rather marvellous films. We have our own video
equipment and editing table, so the films are cheap to make, and we hope teacher
training centres will use them.
With similar local resource methods, we can demonstrate a great deal of
curriculum material from primary to second year university physics and
technology, though at the higher levels we use materials available in towns,
much of it from rubbish piles on the street corners. Mozambique is especially
good on street garbage. We buy some stuff from street stalls and very
occasionally from shops - for example certain tools for higher level work. But
our main principle is that in general the things must be extremely accessible to
lots of children and teachers.
Chicken netting is just one of our many examples. A better one would have
been our solar cooking demonstrations. Villages do not need magnets but they do
need solar cookers. However, we find that it does not matter where we start.
Once young people find they can do practical, fascinating things, they will take
an interest in almost anything. In fact we started these activities many years
ago with music, but that is another story.
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