By
Paul Mooney
Many people across the North East are interested in weather facts
and figures and would love to record their own observations. Professional
weather observing equipment is prohibitively expensive for most people,
so let's have a go at making our own weather recording equipment.
The
instruments are cheap and easy to make and use recycled goods. In
fact they're so easy to make, that even I can do it, although I
did need a bit of help from my eight-year-old daughter, Katie.
The
first instrument we're going to make is a barometer. These are devices
that indicate changes in air pressure.
The
ones you buy in the shops are expensive, but decorative. The one
we'll make is much less expensive, but I have to admit, slightly
less decorative too!
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What
you'll need:
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- One
clear glass or plastic jar
-
One piece of transparent tube,
a drinking straw is ideal
-
Sticky tape
- A
little bit of modelling clay
- Some
cold water
- a
few drops of food colouring.
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Put
some cold water into the jar, so that it's less than half full.
Add
some food colouring, this will make it easier to make your readings.
 Put
the straw into the jar and tape it to the inside, so that the bottom
end of the straw is in the water, but not touching the bottom of
the jar.
Suck
the water halfway up into the straw and pinch it to trap the water.
When
you take your mouth off the straw, keep pinching it until you get
the piece of modelling clay over the top to block it.
That's
your barometer made.
The
only other thing you need is some method of recording changes in
the level in the straw. You could attach a piece of paper on to
the outside of the jar and mark it each day, or you could use an
elastic band around the jar.
Leave
in a place where it's unlikely to get knocked over, (especially
if you used a lot of food colouring) where it's not too draughty,
and not too sunny.
When
the atmospheric pressure rises, the water in the jar will be forced
downwards which will, in turn force the water in the straw to rise.
So, rising air pressure, rising water in the straw and vice versa.
This
is your first step in observing the weather patterns. As a rule
of thumb, when the air pressure is rising, the weather is generally
going to be "quiet and settled", generally dry.
But
when the pressure is falling, the weather will be turning more unsettled,
perhaps with the approach of a frontal system, for instance.
Of
course, as is always the case with the weather, these are not hard
and fast rules.
You
should remember that rising pressure doesn't always mean dry weather…so
don't make arrangements for your Golden Jubilee Street Party based
solely on the measurements from your jam jar barometer, listen to
the forecast on Radio Newcastle too…just to make doubly sure!
In
the next section, I'll explain how to make your own weather satellite.....Only
joking, I'll actually be talking about rain gauges.
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