Karate Test Stand

Hamline University started offering Workshop Physics in the fall of 1996. Since then we have developed a number of equipment pieces to help make the curriculum both inexpensive and useful within the constraints of our space. The Karate Test Stand described below is used in the Workshop Physics curriculum to show students how much energy is required to break a board in a static situation. The total cost of the test stand is around $50-$60. A list of materials follows:

Two foldable saw horses.
A 24" 2x12 (the brick shelf).
4 eye-bolts, washers and nuts (which are drilled and attached or screwed into the shelf at each corner to hang from the cables).
6 small u-bolts (for fixing the steel hanging cable).
2 lengths of steel cable (~3 feet each, which is attached through the eye-bolts on each end, and fixed in place by small u-bolts in 3 places: one on each end, and one in the middle to make a small loop to go around the hanger-bar).
A 1"x1"x18" steel (or AL) bar (hanger-bar). This bar lies parallel to the saw horses and rests on the board to be broken. On each end, the loops of cable are placed over it to hang the brick-shelf from it.
A dial-indicator (1"-2" travel). This is fixed via clamps to the saw-horses to measure the deflection of the board as bricks are added. Clamps of almost any type can be used.
A lot of bricks (~70 lbs.)

Jim Pridgeon assembled and helped design this work of eduational art. The original design is from Hans Pfister of DIckinson College. We don't claim any supperiority, but like this design pretty well.

Here are some photos of the device. First a view of the saw horses:

Next two views of the completed apparatus:

side view

end view

And finally, some close-ups of the rigging:

Dial Close-up

Brick Shelf

For more information contact Ted Hodapp.

How about visiting the Workshop Physics homepage? Find out what is new in this unique curriculum.

Or visit my Home page's section on pedagogy.

If you have questions about this web document, please contact the author, Ted Hodapp.
Workshop Physics is being offered through Hamline University's Physics Department

Hamline University Home Page.