Final answer:
Atmospheric pressure is the force exerted by the weight of the air in the atmosphere, measurable by a barometer, and varies with altitude and weather. Liquid pressure is the force exerted by the weight of a liquid above a point and increases with liquid depth. Both concepts relate to the force per unit area exerted by a fluid but differ in the fluid type and factors affecting them.
Step-by-step explanation:
The difference between atmospheric pressure and liquid pressure lies in the type of fluid and where the pressure is exerted. Atmospheric pressure is the force per unit area exerted against a surface by the weight of air above that surface in the Earth's atmosphere. It can vary due to weather patterns and decreases with altitude, becoming less as one goes higher above sea level. The average atmospheric pressure at sea level is about 1 atm, which is equivalent to 101 kPa or 760 mm Hg. This pressure can be measured using a barometer, typically involving mercury as the liquid.
Liquid pressure, on the other hand, is due to the weight of a liquid above a certain depth. Unlike atmospheric pressure, liquid pressure does not depend on the atmosphere but increases with the depth of the liquid because of the weight of the liquid above. Liquid pressure can also be measured with variants of barometers or other devices like pressure sensors designed for liquids.