A large cooler is filled with water, as shown below. A large yellow cooler with a white valve at its bottom. How does the valve on the cooler compare with the switch in an electric circuit? Opening the valve allows water to flow, just like opening a switch allows charges to flow. Opening the valve stops the flow of water, but closing a switch stops the flow of charges. Closing the valve stops the flow of water, but opening a switch stops the flow of charges. Closing the valve allows water to flow, just like closing a switch allows charges to flow.