why we cant use water in barometer?

Answer 1

It isn't true that we can't use water in a barometer there are units to measure atmospheric pressure in cmH2O (for water) like mmHg (mercury)
However, the use of water in a barometer is limited as it does not work in freezing temperatures i.e. 0' and down unlike mercury. Using water is also rather impractical as just measuring pressure at sea level would already be several metres tall, thus mercury which has a far higher density i.e. approximately 13594 kg/m3 so the height of the mercury column is less and thus easier to use in the many experiments.

Answer 2

Water Based Barometer

Answer 3

As in a barometer we measure sthe pressure (mainly atmospheric ).
the formula used is
Pressure=Density * Height * g
For water density is low thus the height for one atm pressure is about several meters and the instrument of a such height cant be handeled easily ,thus for this purpose Mercury is filled inside the barometer tube to measure the pressure .

Answer 4

The temperature coefficient of water is very less hence the change in volume of water in slight increase of temperature does not change its volume appreciably.
Whereas in Mercury the temperature coefficient is very high hence the volume change for same inc. in temperature is high.
Mercury also has a very high density (13.6 g/cc) hence by the formula hrg where r is the density ,h is the height, g is gravity .
when r is large h is less hence barometers can be made use practically.
Another interesting feature of mercury is that it does not stick to the walls of the glass container unlike water.

Answer 5

Hey dear we can use water in barometer. There is also a type of barometer that is called "Water-based barometer". For more detail see:

(http://en.wikipedia.org/wiki/Barometer)

Answer 6

Because it takes 32 feet of water to balance atmospheric pressure. Besides that, water freezes at too high a temperature to be useful in even moderate climates, and besides that, the density of water changes too much with temperature.

Mercury has none of these disadvantages.

Answer 7

We can but we will need a 10 m long tube. Mercury is about 13.6 times denser than water. Using mercury, the level will rise to about 0.76m due to atmospheric presssure. But using water the column wil rise to 13.6 x 0.76 ie about 10.3m. So its not practical to use water.

Answer 8

It is too light ,it will boil and it will freeze.

Answer 9

It will evaporate!