anonymous one year ago Mercury barometer discussion

1. anonymous

The tallest column of water that atmospheric pressure can support is 10.3 m. If you try to "suck" water up an 11 m straw, it will not reach your mouth. Even if you remove all the air from the straw, a feat that you can't actually do with your mouth, atmospheric pressure will only lift the water 10.3 m up the straw.

2. anonymous

Guys be aware you are not sucking in water you are reducing pressure in the straw.

3. MrNood

|dw:1439741255687:dw| The space above the mercury is filled with saturated mercury vapour. the saturated vapour pressure of mercury is very low the open end has atmospheric pressure to balance the pressure the mercury level is different in each tube the pressure difference due to the height difference is rho * g * delta h so - as the atmospheric pressure changes - so does the delta h in the 2 sides of the tube

4. anonymous

I would believe this fancy equipment would have to be build on the earth's surface to be functional eh?

5. anonymous

I've heard of instances where the mercury actually leaked out of the barometer

6. anonymous

made a spill, also skin irritation

7. MrNood

the pressure difference as I stated is rho * g * h it will work in any environment with gravity (the scale factor will be different. But would not work in 0 gravity environment

8. anonymous

I bet if mercury's ingested central nervous system would be quite disturbed

9. anonymous

you mind clarifying what rho stands for my ignorance?XD

10. MrNood

mercury vapour is highly poisonous. You can no longer purchase mercury bartometers in UK. Not sure what the laws are in other parts of the world

11. MrNood

rho is the greek letter $\rho =$ it is used to represent the density of a substance

12. MrNood

the equivalent value for 'sucking' mercury is 760mm of height. Atmospheric pressure is sometimes stated as '760mm Hg' but this is not a true measure of pressure - it is an analog of it