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Weather recorders


 

All over the UK there are weather stations sending in reports to the Met Office in Exeter every day.

Weather station

A standard weather station will have a thermometer screen, thermometers, a rain gauge and an anemometer for measuring wind speed and direction.

Rain gauge

The standard rain gauge is made of copper. The rain runs into a funnel and into a bottle. The water is then collected once a day and measured in measuring cylinder. These are now being replaced by automatic rain gauges which can record rainfall every minute.

Thermometer screen

This is a white box which is positioned high off the ground. This is called a Stevenson Screen. It has special vents to let the air flow freely. Inside the screen are four thermometers. Two of the thermometers measure the maximum and minimum thermometers. The other two are used to record the current air temperature and the humidity. They are identical but one has the bulb covered in a white cloth which is kept wet by being dipped in (distilled) water. These are called 'dry bulb' and 'wet bulb' thermometers. The difference between these two can be used to measure the humidity. New thermometers have now been developed which measure these temperatures electronically and can display their information on a computer screen.

Campbell-Stokes sunshine recorder

Campbell-Stokes sunshine recorder This looks like a crystal ball. The glass ball works like a lens and focuses the sun onto a strip of special card. As the sun moves across the sky it burns a track into the card to show how many hours the sun has been shining. This was invented over 100 years ago, but like many pieces of weather equipment it is now being replaced by automatic electronic devices.
  Fig 1: Campbell-Stokes sunshine recorder.

Radiosondes

Balloons carrying small weather stations are sent up from stations around the UK at 12 noon and midnight. They send back to the ground measurements such as temperature, humidity, wind speed and direction from high in the atmosphere.

Admiral Beaufort

Admiral Beaufort

The Beaufort wind scale can be used to measure wind strength. It was written by Admiral Beaufort who was commander of HMS Woolwich. He lived from 1774 to 1857.

There are two scales, one for use on land and one for use at sea.
Admiral Beaufort  

Let’s find out

Find a copy of the Beaufort Scale and make a record of the wind over a period of two weeks. Try this at different times of the year.

Design your own weather log. You could do this using a book or a simple computer program.

Ask some grandparents to come in and talk about what the weather was like when they were younger. See if they have any photographs, which would give you a clue as to the weather when they were children.

Things to make

This is a simple barometer.

You will need:

  • a small plastic bottle;
  • a water tight tray or dish;
  • a measure;
  • plasticine;
  • card;
  • scissors;
  • pencil.
A simple home-made barometer
  Fig 2: A simple home-made barometer.

Fill the bottle about three quarters full of water, and also half fill the dish. Put your fingers over the end and turn the bottle upside down into the tray/dish of water. Do not remove your fingers until the neck of the bottle is under the water.

Fix the bottle so that it is standing upright. Mark the level of water on the side of the bottle. As the pressure rises and falls so the level of water changes. Your barometer is one piece of weather equipment that you can keep inside.

If the air pressure is high, the weather is usually fine. If it is low then the weather is usually cloudy and wet.

Amazing facts

Waterspouts are like tornadoes but they form over water rather than land. They suck up water and spray from the sea and lakes. Sometimes they also suck up fish. They can be one or two kilometres high.

The first weather satellites were put into orbit in 1960.

One of the driest places on earth is Arica in Chile (South America), where only 0.76 mm falls every year. A coffee cup would take around 100 years to fill!
A waterspout
  Fig 3: A waterspout.