Range

Materials:

  • Four (4) Wires
  • Batteries Block
  • LED Block
  • Potentiometer Block
  • Push-button Block
  • Photo Cell Block (optional)

Make a circuit with the Batteries Block, Potentiometer Block and LED Block. Turn the potentiometer all the way clockwise. Now rotate it all the way counterclockwise. What happens to the LED as you do this? Describe what you see. What are you doing with the potentiometer? What do you DO with the potentiometer that you DO differently with a switch? What HAPPENS differently with the LED when you use the potentiometer rather than the push-button?

Similar to how a faucet varies the amount of water that can flow, a potentiometer controls the flow of electricity by varying the resistance. Unlike a switch, the potentiometer controls over a range - for example the LED may go from dim to dimmer to dimmest as the potentiometer is rotated counterclockwise. Likewise the LED will continue to get brighter as the potentiometer is rotated clockwise. 

Take your fourth wire and add the Push-button Block into the pathway of your circuit, along with the Batteries Block, Potentiometer Block and LED Block. Explore how the push-button and potentiometer can work together. Can you make your LED flash brightly? Can you make your LED flash dimly? What other patterns can you make with the potentiometer and push-button together?

As an extension, set up a circuit with a Photo Cell Block instead of a Potentiometer Block. Use a flashlight to experiment with how the photo cell is controlling the electricity in the circuit. You might want to substitute the LED Block for the Buzzer Block (and also remove the Push-button Block) and explore this circuit next to a window or other source of light.