Assembly  Extensions  Data  Activities page
  1. Cut one of the meter long threaded rods down to 75 cm, leaving the other full length.

  2. Cut one of the 61 cm threaded rods down to 45 cm, leaving the other full length.

  3. Drill a 1/4 inch hole through the center of one of the short sides in each of the 15 cm pieces of wood.

  4. Hammer a tee nut into the hole on one end of each 15 cm piece.

  5. Countersink four 3/4 inch holes about 1/8 inch deep into the 45 cm 2 x 4 at 12 cm intervals, as marked on the diagram. (This will allow you to countersink the nuts so they don't scratch the surface where the model rests.

  6. Drill four 1/4 inch holes in the 45 cm 2 x 4 in the counter sunk holes.

  7. Hammer a tee nut into each countersunk hole. Turn the board over so the tee nuts are on the bottom.

  8. Assemble the rods and the base as shown on the diagram.

  9. Use the permanent marker to label the 15 cm 1 x 4 inch blocks in order 1, 2, 3, and 4.



This experiment can be run using computer aided software and sensors for very accurate data collection.

List of materials

We used an old 386 laptop. A high speed machine is not necessary.
Low G accelerometer, Force sensor and serial box plotter
These, along with the software,were purchased from Vernier software company. The cost for these was about $250
Five 3/16 inch x 1 inch screws are used to attach the accelerometer. Self tapping metal screws are the best and cost about $0.50 at the hardware store. One will be used to attach the force meter to the cart.
Small casters
Used to make the whole experiment move on the track. Four 1 inch casters will work well. Cost: about $5.
Angle Iron
Two three foot pieces of angle iron are used to make a small track to hold the experiment (The kind with a bunch of holes drilled in it is the best). The force meter will then be attached to this and the cart. Cost: about $4.
Flat strap
Two 12 inch pieces of flat strap (similar to the angle iron but flat) are used to hold the angle iron together. Cost: about $2.
Four 1/4 inch x 1 inch bolts with nuts and washers to fit are needed to hold the track together. Three smaller bolts and nuts will also be needed to attach the force meter to the track and cart. 3/16 inch x 1/2 inch will do. Cost: about $1.50.
Four 1 inch L brackets are used to connect the force meter to the track and cart. Cost: $2.50.


This is very easy to construct and will give very accurate results.


Step 1)

  • The accelerometer must be attached to one of the small blocks.
    • Place the accelerometer in the middle of the small block and mark the placement of the holes using a narrow pin or marker.
    • Then simply screw the accelerometer down to the block. Be careful not to tighten it too much or it may break.


Step 2)

  •  This block can then be moved between the different lengthed rods to collect the data for each trial
  • Attach the casters to the bottom of the BOSS model about 1 inch in from each edge.


Step 3)

  • The angle iron should be attached using the straps and bolts so that the cart will fit loosely but the wheels should ride on the angle iron.
  • The L brackets now need to be made into two Z shaped brackets using the 3/16 inch bolts. One of the Z's will attach to the force meter
    and the track the other should be attached to the force meter and the cart.


 Basic Model  Extensions   Data  Activities page

Created By Dave Love, Chris Durand and John Van Der Kamp Last updated 11/13/99


last modified: 25 April, 2022