This dramatic demonstration shows several principles at once. The massive cinder block is set at rest on a person's chest or stomach. The much less massive sledgehammer strikes it causing the block to break. This can be explained in terms of Newton's Laws, Energy, and Pressure.
* Equipment seen in the video may vary from equipment used in ND Demonstrations. See information and images below for ND equipment and setup.
Setup:
Place the cinder block on the persons chest or stomach so that the flat side is facing up.
Once the person is ready, count down and swing the sledgehammer to strike the block slightly to the side of the center beam causing it to break.
Notes:
This demo must be practiced ahead of time for safety reasons.
CAUTION: This demonstration is dangerous and is performed at the instructors own risk.
This demonstration may also be done by smashing a cinder block on top of a bed of balloons as shown below.
Courses Used In:
PHYS 10111
PHYS 10310
PHYS 10410
PHYS 30210
Discussion and Polling Questions:
Why does the person underneath not feel like they were hit by a sledgehammer?
Alternatively, why do the balloons not pop?
Equipment Needed:
Sledgehammer
Cement Block
Safety Glasses
Face shield
Trusted Individual to Swing the Sledgehammer
For alternate version with bed of balloons:
Balloons
Wood Board
Balloon Cage