What is the weight of 1 gallon of water?
The correct answer and explanation is:
Correct Answer:
1 gallon of water weighs approximately 8.34 pounds (lbs) at standard temperature (around 62°F or 17°C).
Explanation (300 words):
The weight of water depends on its volume and density. A gallon is a unit of volume, and pound (lb) is a unit of weight (mass under Earth’s gravity). To find the weight of 1 gallon of water, we must know the density of water and the volume of a gallon.
In the U.S. customary system, 1 gallon equals 128 fluid ounces, or 3.785 liters. The density of water at room temperature (approximately 62°F or 17°C) is about 1 gram per cubic centimeter (g/cm³) or 1,000 kilograms per cubic meter (kg/m³).
To convert from volume to weight:
- 1 liter of water weighs 1 kilogram.
- Therefore, 3.785 liters weigh about 3.785 kilograms.
- Since 1 kilogram = 2.20462 pounds,
3.785 kg × 2.20462 = 8.34 pounds.
This means 1 U.S. gallon of water weighs approximately 8.34 pounds.
Note that this value can vary slightly depending on temperature and impurities. Water becomes less dense as it heats up and more dense as it cools (until about 4°C), so the weight of a gallon of water will be slightly less if it’s hot, and slightly more if it’s cold.
Also, be careful not to confuse U.S. gallons with Imperial gallons used in the UK and some other countries. An Imperial gallon is larger—about 4.546 liters, and so weighs approximately 10.02 pounds.
Understanding the weight of water is important in many practical fields like plumbing, construction, and health (hydration tracking), since carrying or storing water involves managing its considerable weight.