bar is just the sensible scale for Pascal (1mbar = 1hPa), where 1 bar is about exactly standard atmospheric pressure. Beware though if you see bar scales it’s often not an absolute but overpressure scale, if the tyre pressure gauge says “1 bar” it means 1 bar over atmospheric pressure, that is, about 2 bar. 1 bar is also about the pressure of 10m of water.
atm is metric, too, with 1atm being exactly standard atmospheric pressure, toss it for bar. mmHg is only used in medicine, not used for actual calculations back in the days where blood pressure was first measured they did it with mercury scales and there was never any reason to change, on the contrary, changing would only introduce confusion. Torr is the same as mmHg, forget about it. The rest is colonial nonsense.
bar is just the sensible scale for Pascal (1mbar = 1hPa), where 1 bar is about exactly standard atmospheric pressure. Beware though if you see bar scales it’s often not an absolute but overpressure scale, if the tyre pressure gauge says “1 bar” it means 1 bar over atmospheric pressure, that is, about 2 bar. 1 bar is also about the pressure of 10m of water.
atm is metric, too, with 1atm being exactly standard atmospheric pressure, toss it for bar. mmHg is only used in medicine, not used for actual calculations back in the days where blood pressure was first measured they did it with mercury scales and there was never any reason to change, on the contrary, changing would only introduce confusion. Torr is the same as mmHg, forget about it. The rest is colonial nonsense.