module.exports.WATER_DENSITY = WATER_DENSITY = 1000  # kg / m^3
module.exports.AIR_DENSITY = AIR_DENSITY = 1.225  # kg / m^3
module.exports.VACUUM_DENSITY = VACUUM_DENSITY = 0.00000000000000129  # For an excellent laboratory vacuum; kg / m^3
module.exports.SWAMP_DENSITY = SWAMP_DENSITY = WATER_DENSITY / 4  # Swamp is dense like water, but only covers part of unit
module.exports.STANDARD_FRICTION = STANDARD_FRICTION = 0.7  # 0.7 =~ shoe on floor.
module.exports.ICE_FRICTION = ICE_FRICTION = 0.1  # As low as 0.015 (steel on ice), as high as 0.4 (rubber on ice)
