The weight of water depends on its volume and density. For water, the density is approximately 1 kilogram per liter at room temperature.
1. Density of Water
Water is known to have a density of 1 kilogram per liter (kg/L) at room temperature (around 20°C or 68°F). This means that for every liter of water, it will weigh exactly 1 kilogram.
2. Volume and Weight Conversion
Given that the density of water is 1 kg/L:
- 1 liter of water weighs 1 kilogram.
- Therefore, 3 liters of water weighs 3 kilograms.
This is a direct relationship based on the volume of water. Since the density is 1 kg/L, for every liter of water, the weight is the same in kilograms.
3. Converting Kilograms to Pounds
In many parts of the world, particularly in the United States, the weight of objects is often measured in pounds rather than kilograms. To convert kilograms to pounds, we use the following conversion factor:
1 kilogram = 2.20462 pounds.
To convert 3 kilograms to pounds:
               3kg×2.20462pounds per kg=6.61386pounds.
So, 3 kilograms of water equals approximately 6.61 pounds.
4. Why Does This Work?
Water has a very consistent density of around 1 kg/L at room temperature. The density can slightly change depending on the temperature of the water, but for most practical purposes, 1 kg/L is a good approximation. In colder water, the density increases slightly (which means it could weigh a bit more per liter), while in warmer water, the density decreases slightly, making it weigh slightly less.
Summary:
- 3 liters of water weighs 3 kilograms (since 1 liter = 1 kilogram).
- 3 kilograms of water weighs about 6.61 pounds (using the conversion factor of 1 kilogram = 2.20462 pounds).
So, when dealing with water, you can use the simple conversion that 1 liter = 1 kilogram, and then convert to pounds if needed by multiplying by 2.20462.