> the nice water/gravity correpondence Also: 1 atm (normal atmospheric pressure) is 1 kg / cm^2. Or the pressure of 10 meters of water (a column of water 10 m

> the nice water/gravity correpondence Also: 1 atm (normal atmospheric pressure) is 1 kg / cm^2. Or the pressure of 10 meters of water (a column of water 10 meters tall, to be precise). 1kg of mass under normal gravity generates a gravitational force of ~10N. It's super-easy to do everyday physics in your head, no calculator required, in the metric system.