• Name: Munawar Karim
  • Address: Dept. of Physics, St. John Fisher College, Rochester, NY 14618
  • Phone: 716 385 8365
  • Fax: 716 385 7311
  • E-mail: karim@sjfc.edu


    Apparatus Title: Acceleration Demonstrator


    Device to demonstrate both direction and magnitude of linear and centripetal acceleration.

    Equipment required to construct apparatus:

    Toy car and radio-control unit from Radio Shack, clear plastic tube 1/2" diameter, total length about 4 ft. Elbow joints, glue, fixing hardware.

    Item Source/Store Part Number Cost

    Total cost...$50.00

    Sketch of the apparatus


    I have equipped a toy radio-controlled car with two orthogonal accelerometers. These are simple plastic U-tubes filled with colored water. One U-tube is aligned forward and backward, the other sideways. One of the U-tubes is filled with green and the other with red colored water. The top ends of the U-tubes are connected together using clear plastic tubes (this prevents water overflow). Acceleration is demonstrated by running the car. Forward-backward acceleration is evident when the car accelerates from rest, the water level in the forward-backward U-tube moves towards the rear, opposite when the car stops. Centripetal acceleration shows up in the unequal level of water in the sideways U-tube when the car is turning. The magnitude of the accleration is proportional to the height difference of the water level in a U-tube. One can show the independence of the two components of accleration, as well as the magnitudes. Kids also have fun driving the car!