Jugs and Mugs - Measuring Liquid Volume

Capacity is the maximum amount of liquid a container can hold. Imagine a clear water bottle filled exactly to the top; the amount of water inside represents its total capacity.

The standard units for measuring liquid volume are Liters ($L$) and Milliliters ($ml$). Liters are used for large quantities, like a bucket of water or petrol in a car tank. Milliliters are used for small quantities, like a spoon of medicine or a small carton of juice.

To visualize the difference between units, imagine a large $1$ $L$ milk carton next to a tiny eye-dropper. It takes many drops to make even $1$ $ml$, and it takes $1000$ $ml$ to fill that $1$ $L$ carton.

Measuring jugs often have markings on the side called a scale or graduations. To find the volume of a liquid, you look at the level of the liquid against these horizontal lines. If the liquid reaches the mark labeled $500$ $ml$, the volume is exactly $500$ $ml$.

Conservation of Volume: The amount of liquid remains the same even if it is poured into a container of a different shape. For example, if you pour $250$ $ml$ of water from a tall, thin glass into a wide, flat bowl, the volume is still $250$ $ml$ even though it looks shallower in the bowl.

Adding and Subtracting Volume: When combining liquids, we add the Liters to Liters and Milliliters to Milliliters. For example, if you have two jugs of water, you can find the total by adding their measurements together.

Conversion Rule: Since $1$ $L = 1000$ $ml$, you can convert Liters to Milliliters by multiplying the number of Liters by $1000$. Conversely, $500$ $ml$ is exactly half of a Liter ($\\frac{1}{2}$ $L$).