Videos of Breaking Boards

The following QuickTime videos were made with a Redlake Imaging MotionScope. They were recorded at 250 frames per second.

For a description of this experiment, see Unit 10 of the Workshop Physics Activity Guide,
by Priscilla Laws (published by Wiley).

The next three videos were made by dropping an object on a board to break it. Each board was marked with a green sticker at the middle, and red and blue stars on the midpoints of its right and left sides, respectively. The red and blue stickers near the ends serve to identify the end. The title screen shows the initial mass of the board and of each of its major fragments. The boards were initially held in place by masking tape to minimize the transfer of momentum to the supports.

  1. Iron Ball shows an iron ball (with a visible hook) falling on a board.
  2. Lead Ball shows a somewhat dented lead ball (with a visible string) falling on a board.
  3. Lead/Clay Blob shows the same lead ball as in the previous movie, but with a small blob of green florist's clay on its bottom. This makes the collision more inelastic. The lead and clay were covered with plastic wrap to prevent the clay from sticking to the board.


Freefall collision:

Andy Jacobs, a senior physics major, built a device that releases a board just before it is hit by a falling ball. Here is a photo of Andy cutting the string to release the ball:

Here is a video he made. Click on the picture to get the whole QuickTime file.

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This material is based in part upon work supported by National Science Foundation (NSF) grants 0089380, 0424063, 0717699 and 1122828. Any opinions, findings and conclusions or recomendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.