weather [2] [information over pictures]

The lines on the map are called isobars. The numbers on the lines are the air pressures recorded on a barometer measured in millibars.	A cold front occurs when cold air overtakes a warm front then cold temperatures occur, frequent rains and drier air.	A warm front occurs when a warm air mass overtakes a cold air mass. then Light to moderate rain, a lot of humidty and higher temperatures.
An occluded front occurs when a warm front overtakes a cold front then severe thunderstorms can be expected.	In a stationary front two different air masses are stationary and unmoving because of a boundary of air and when neither air mass is advancing into the other.	On this map you can see isobars, a cold front, a warm front and an occluded front.

Look at all of the pictures in turn. As you hover over each one a blue screen appears with an explanation of what the picture shows. Important words are coloured. If you are certain that you know about the picture click on it and it will disappear. As you go through all of the pictures you will get rid of all those which you know about and be only left with those you may be unsure of. In some cases you may get rid of all of the pictures in which case you are ready to move on to other activities which will test your knowledge on that particular topic.