Projectile Motion - or  "Can you project a marshmallow into a bucket?"

 Marshmallow Siege Catapult

 Materials:

1-cup milk carton

scissors

small rubber bands, assorted sizes and widths

toothpicks

two pencils

small matchbox

marshmallows

 Procedure:

1.  Cut off the top of the milk carton and then cut the carton as shown in Figure 1.  Cut holes the size of a pencil in both sides and in the back, as shown

 2.  Push a rubber band through the hole in the back and hold it in place with a toothpick.  Push a pencil through the holes in the sides.

 3.  Cut the tray of the matchbox in half lengthwise and tape it to the sharpened end of the pencil.  If you do not have a matchbox, make a similarly shaped holder out of paper and tape. 

 4.  Lay this pencil across the other with the eraser end facing the front of the catapult.  Loop the rubber band over the eraser end.  Fold the front flap of the milk carton in, crease it, and tape it down. 

 5.  Place a marshmallow in the holder, pull back the pencil, and fire.

 

Challenge:

 The challenge is not to just fly the marshmallow the farthest.  Distance is important but so is control and adaptability.  You must know how to modify your catapult to fit the need of the different contest.

 Contest #1:  On the lab counter, you must fly the marshmallow horizontally a distance of _______ cm and land it in a shallow pan the size of a sheet of paper.  You will be given 3 practice tries and two actual attempts.

 Contest #2:  With your catapult on the lab counter, you must fly the marshmallow horizontally a distance of ___________ cm and land it in a bucket on the floor.   As you can see this adds the complexity of changing vertical and horizontal distances.  Again you will be given 3 practice trials and 2 attempts.

 Contest #3:  With your catapult on a lab stool you must fly the marshmallow over open space onto the lab counter and into the shallow pan.  The distance between catapult and target is ____________ cm.

 Bonus:  Calculate the energy involved in flying your marshmallow.    This would be potential (mass x gravitational acceleration x height) and kinetic (1/2 mass x velocity squared).  Also look at the angles involved in your attempts.