Apologia Physics: Impulse and the Egg Drop demonstration/competition

Impulse is the energy change to an object when a force is applied to an object in a short period of time.  Think about hitting a baseball with a bat. The ball changes direction and is hit out into the field owing to the application of force by the bat to the ball.  Conversely, think about dropping an egg on the floor.  The egg gains momentum as it falls to the floor and is suddenly stopped when it hits the floor.

We know that momentum is mass times velocity.  p=m.v  UOM typically kg.m/sec  There is no name for this UOM.

Newton's second law says that Force = mass.acceleration
Newton' third law says that for every action there is an equal and opposite reaction

We also know that acceleration = change in velocity/change in time
Therefore Force = m.change in velocity/change in time
which can also be stated as F=(mvfinal - mvinitial)/change in time
Force = change in momentum/change in time
which can be restated as change in momentum = Force .change in time

If you want to hit the baseball further, you swing the bat harder thus increasing force tand you also want to "follow thru" and maintain contact longer.  Both will increase momentum of the ball.

For the egg drop and egg throw, the change in momentum is the mass of the egg times the velocity at which you throw the egg or the speed of the egg as it hits the floor.  If we calculate this momentum and plug it into the impulse equation as a fixed amount, then our goal, if you don't want the egg to break is to increase the time thus decreasing the force.

The students will demonstrate this by catching a thrown egg with their bare hands, a cookie sheet, and a bed sheet.  For their Lab Report, they should give a background on impulse and momentum, procedure including how they reduced impulse so they could catch the egg without it cracking.

They will also construct an egg package which will cushion the landing of the egg.  We used bubble wrap, egg cartons, and lots of tape!  Be sure to leave a window in the container so that you can determine when the egg has cracked.  We dropped the egg from three, four, five, six, and seven feet.