1. Water displacement method: This method involves submerging an object in a graduated cylinder filled with water and measuring the change in water level. The volume of the object is equal to the amount of water displaced. If the object has an irregular shape, you can place it in a plastic bag before submerging it to make it easier to measure the volume.
2. Mass and density: The density of a substance is its mass per unit volume. If the density of a liquid remains constant, then its volume must also remain constant. You can measure the density of a liquid by dividing its mass by its volume. If the density does not change, then the volume must also remain constant.
3. Observation: In some cases, you can simply observe a liquid to see if its volume changes. For example, if you pour water from a tall, thin glass into a short, wide glass, the water will spread out and cover a larger surface area. However, the volume of the water will remain the same.
