Water and Funnels

When playing with water, children can make use of funnels to fill containers more easily. Using the wide mouth of the funnel, some children were able to fill their spray bottles (that had narrow openings) a lot quicker. We can see them using the funnel in the image below.

One thing that could be explored from this activity is the speed at which the water leaves the funnel and how the water level in the funnel decreases. The speed with which the water leaves the funnel will be dependent on the amount of water in the funnel. The more water there is, the faster the water will exit the funnel, as the water above will force the water at the bottom out. The size of the opening at the bottom of the funnel will also affect how quickly the water can flow out. If the children had access to multiple funnels, they could experiment with them, making note of the different properties each funnel had.

As water exits the funnel, the water level will change at different rates. This is because the cross-sectional area decreases as we move down the funnel. This is also a situation that happens when filling up bottles with thin necks. At first, the bottle will appear to fill slowly, and then as it reaches the top, the bottle will appear to fill faster. This is because we get to the neck of the bottle, where the cross-sectional area is smaller. To read more about experiments with water, see our articles on experiments with water and buoyancy.