Question

How can we determine the weather condition with decrease or increase in level of mercury of simple barometer

Answer 1

Since changes in air pressure are a good tool to use to forecast the weather, barometers are very useful. Isobars show where the locations of areas of equal pressure are. They are placed on weather maps. Local weather can be forecast using several guidelines:
1. A falling barometer means the air pressure is decreasing and is an indication that there will be wind, storms, and rain.
2. A rising barometer means good weather is likely.
3. If the mercury in the barometer is falling slowly, change in weather is not likely.
4. If there is a rapid decrease in the height of the mercury, then a storm is likely to happen.
5. If there is a slow, sustained falling of the mercury in the barometer, then there will probably be a long period of poor weather.
6. If the mercury in the barometer is rising quickly, then an improvement of the weather is likely.
7. A slow and sustained rise in the mercury in the barometer indicates long lasting good weather is ahead.