Robert Fitzroy was one of the first meteorologists. While most science concentrates on explaining events in the past and present, meteorology is concerned with weather patterns and our ability to predict what will happen with the weather in the near – and not so near – future.

Weather patterns

Download a pdf of the instructions here.

Make your own barometer!

You will need...

A jam jar or glass.
A straw: a straight one is best, in white plastic or clear so you can see inside it.
Water.
Food colouring (optional, but helpful to see the water inside the straw more clearly).
A small plastic ruler that will fit inside your jam jar.
Sticky tape or parcel tape.
A marker pen that will write on plastic.

How long will it take?

The barometer will take about half an hour to make, but observing the results can go on for months if you like.  You may like to have a discussions session at least a few days after making the barometers, where you look at the patterns in the pressure readings and the weather outside.

What to do...

1.  Have a look at the students' section for instructions.

2.  It is very important to make a tight seal at the top of the straw, as any air getting in will eventually cause the water level in the straw to drop to the same level as the surrounding water.

3.  Have a look at the BBC weather website for a forecast for your area.  It is often best to start this experiment at a time of low pressure so the level in the barometers is likely to rise initially.

4.  As the students make their observations it may be useful to make a note of the official pressure reading to confirm the barometer is working well.  This can be found for your area on the BBC weather website.

5.  If the temperature near the barometer changes too much this can heat the air in the straw and cause it to expand.  You may like to show the students this and then show them an image of a weather station which is protected from the sun and wind (http://www.northantsweather.org.uk/weathertour/screen.htm)

 

Curriculum Links

Science:

Working Scientifically

 

Lower key stage 2 Year 4
States of matter

 

Upper key stage 2 Year 5
Forces

Numeracy:

Measurement

 

Statistics

History:

A study of an aspect or theme in British history that extends pupils' chronological knowledge beyond 1066

 

Scottish Curriculum Links

Science

SCN 2-05a

Planet Earth - Processes of the Planet

Mathematics 

 

MTH 2-12a

Number, Money and Measure - Mathematics - its impact on the world, past, present and future.

 

MNU 2-20a

Information Handling - Data Analysis

Interpreting and drawing conclusions from the information displayed. 

 

MNU 2-20b

Information Handling - Data Analysis

Gathering information and working with others to organise results.

Social Studies

SOC 2-04a

People, Past Events and Societies

Comparing and contrasting a society in the past with my own.

 

SOC 2-06a

People, Past Events and Societies

Discussing why people and events from a particular time in the past were important.

BarometerRobert Fitzroy called it 'forecasting the weather'; we now say 'weather forecast'.  But how can it be done?

The tool Fitzroy used was called a 'barometer'.  A barometer (like the one on the left) measures the amount of air above our heads.  Air is surprisingly heavy and it presses down on everything around us.

 Put your hand on a table, palm up and place about three big books on your hand.  Feel how the books are pressing down on it.  Now remove a book and feel how the pressure is less, add a book and feel how the pressure is more.  The air above our head moves around too, so although it is pressing down on us all the time sometimes it presses down more and sometimes it presses down less. 

When there is more air (more books on your hand), this is known as high pressure and this generally means good weather.  When there is less air (fewer books on your hand) it is known as low pressure and this often leads to bad weather. 

Scientists today still use barometers to help them forecast the weather, but they also have very powerful computers to help them.   As well as pressure, these help take into account the temperature and motion of the air - up to 20km or more - and whether the air is moving over water and picking up water by EVAPORATION, or if the air is moving over mountains where it will rise and cool and the water will CONDENSE and make rain.

How weather patterns move around the world is very complicated, and even today it is only possible to predict weather patterns only 5-7 days into the future.

 

Weather patterns

Download a pdf of the instructions here.

Make your own barometer!

You will need...

A jam jar or glass.
A straw: a straight one is best, in white plastic or clear so you can see inside it.
Water.
Food colouring (optional, but helpful to see the water inside the straw more clearly).
A small plastic ruler that will fit inside your jam jar.
Sticky tape or parcel tape.
A marker pen that will write on plastic.

What to do...

barometer diagram_3001.  Fill your jam jar three quarters full of water, and add a little food colouring (if you have it).

2.  Put in your straw into the water.

3.  Now seal the top end of the straw.  You can do this by carefully flattening the top end of the straw and folding the flattened end over.  Use parcel tape to make the top of the straw completely airtight, but don't put the tape too far down or you won't be able to see the level of the water within it.

4.  Remove some of the water from the jar, so that the water level in the straw sits above the water level in the jar.  You can do this by tipping the jar up, using a syringe, or by using a cloth or tissue paper to soak up some of the water.  Whatever you do, you need to make sure that the open (bottom) end of your straw stays under the level of the water in the jar.

5.  Put the ruler in the water behind the straw, and use sticky tape to hold the straw in place.  Again, make sure the sticky tape does not stop you from seeing the water level in the straw.  You can then use a marker pen to draw the level of the water in the straw.

6.  Leave the straw and jar somewhere where they won't be too hot or too cold, particularly away from windows, and where the temperature tends to stay the same.  And watch it over the first few hours to see whether the water level in the straw is dropping.  If the level of water drops too much you may have an air leak in your straw and you will have to start again.

7.  Watch the level of the water in the straw every day, and see if goes up or down - it won't change by much so you have to look carefully.  Make a note of whether it is higher or lower - or at the same level - as when you first made the barometer and every time also a note of the weather outside. Use a table like the one below.

Date

Height of water in the straw (higher / lower / same level)

What is the weather like?

Actual air pressure in your area

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


 

What is happening?

Air is pushing down on the water in your jam jar.  When the amount of air above our heads increases, the water moves into and up the straw, and the water level in the straw goes up.  When the amount of air above our heads decreases, water moves out of the straw and the level drops.  So when you measured a higher value on your straw you had higher pressure, and when it dropped you had lower pressure.

Did you notice a pattern between the pressure and the weather?  Generally, high pressure means bright sunny weather and low pressure means dull, cloudy weather.