How much does a gallon of water weigh? Simply put, a gallon of water weighs about 8.34 pounds (3.78 kg). However, because the gallon is a unit of volume, not weight, the actual weight of a gallon of water will depend on temperature, surface gravity, height, and pressure.
Gravity, Pressure, And Height:
Gravity is the force exerted by all bodies with mass. Any object with mass will produce a gravitational field, although the magnitude of this field is negligible for very small objects. However, gravity cannot be ignored for large objects such as planets.
Earth creates its own gravitational field and we feel the effects of the gravitational field. lead this daily in his life. It keeps us tied to the surface of our world, and it also affects the weight of objects, including water. The greater the force of gravity, the greater the weight of the object. For example, a gallon of water weighs about 8.34 pounds on Earth at sea level, but that same gallon of water would weigh nearly 20 pounds on Jupiter.
Pressure is similar to gravity in that it can change the weight of an object. Gravity causes pressure, but that’s not the only thing that does. The atmosphere also creates a pressure called barometric pressure. As with gravity, more pressure equals more weight. Barometric pressure will also depend on your altitude above sea level, so the higher you are, the less barometric pressure you will feel. So a gallon of water will weigh a bit more at higher altitudes.
Temperature has a significant impact on the weight of water. When a gallon of water weighs about 8.34 pounds, that’s its weight at 39.2 degrees Fahrenheit (4 degrees Celsius). The actual weight of a gallon of water will vary with temperature because it affects how the water molecules hold together in a particular volume.
For example, as the water gets colder, the The molecules will bind together more tightly, reducing the total mass absorbed by the water and increasing the total density. Thus, colder water will have a higher weight. Meanwhile, warmer water will see its molecules move away from each other, increasing the volume occupied by the water and decreasing the total density. Therefore, hot water will be heavier.