2. Have you ever seen a natural event that surprised

you? Why was it surprising?

I have seen many lightning storms before. However, one of the most surprising ones was when I was at my house. It was around midnight when I awoke from the sound of lightning in the distance. I was also half awake so this could be another reason this was the most surprising, but lightning struck near my area. i could see the light through my curtains and the sound was loud enough to awake everyone in my house, even the deep sleepers. I practically jumped out of bed.

a mercury barometer is a device that uses the physical properties of mercury in a tube to measure barometric pressure. mercury barometers are used for : -

1. measurement of atmospheric pressure  

2. determining the altitude of a place

3. weather forecasting

4. calibration and checking of aneroid barometers

5. application in fluid mechanics

6. measurement of pressure in aircrafts

7. surface weather analysis

8. preparation of barographs

9. usage in physical sciences like physics, astronomy & chemistry

10. preparation of aircraft altimeters

characteristics of mercury barometer : -

1.used to define and measure atmospheric pressure.

2.on the average at sea level the column of mercury rises to a height of about 760 mm.

3.this quantity is equal to 1 atmosphere.

4.it is also known as standard atmospheric pressure.

5.a barometer in which the weight of a column of mercury in a glass tube with a sealed top is balanced against that of the atmosphere pressing on an exposed cistern of mercury at the base of the mercury column, the height of the column varying with atmospheric pressure.

i need mutiple choices