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PRESSURE - Coggle Diagram

- - - - This is also the reason why, if we make small holes along the side of a bottle full of water, the water will come out at a narrower angle in the upper part, a wider one in the lower part.
- - - - If the liquid column is at rest, force = weight
        
        weight = mass x g (acceleration due to gravity)
        
        mass = volume x density(ρ)
        
        volume = A x h
        
        density(ρ) = mass/volume
        
        force exerted at the bottom = A x h x ρ x g
      - (A x h x ρ x g)/A = h x ρ x g
- - - - Atmospheric pressure acts outside the tube. Inside, the pressure due to mercury acts. The liquid tends to flow from the inside to the outside because there is a pressure difference between the tube and the container.
        
        What will we see?
        
        The height of the mercury column will reach 76 cm, while the atmospheric pressure will continue to be exerted externally.
        
        The mercury stops at the level corresponding to 76 cm because at that point there is no longer any difference between the pressure inside the tube and the external one.
        
        76 cm = barometric height
        
        At higher altitudes than the sea level the atmospheric pressure decreases, therefore the level of mercury in the tube will drop below 76 cm.
        
        How to calculate atmospheric pressure
        
        h (height of the mercury column) x ρ (density of mercury) x g = 13 600 kg/m^3 x 0.76 m x 9.8 m/s^2 = 101325 kg/ms^2 = 101325 Pa
  - - - 2. On the contrary, if the air temperature drops, the atmospheric pressure increases.
        
        3. Atmospheric pressure also decreases when air humidity increases: steam decreases mass and, consequently, also density.