Student responses to the function of water level difference in relation to voltage.
| Water level difference | Function |
| Type 1 | Allows water(current) to flow The force that pushes(flows) electric current The ability of voltage to cause current to flow, just as water flows due to a difference in height Power, Power to go, Power to make the watermill turn Water pressure Electic force |
| Type 2 | Determines the strength of water(current) The greater the voltage, the brighter the bulb Voltage controls the brightness of the bulb Determine the intensity of light Strength of electricity The power of one electron Energy(electricity) size, etc. |