5.6D: Experimenting with Forces
Force, Motion, and Energy
Marshmallow Catapult
Project:
Make your own
marshmallow
catapult to
experiment with
projectile
motion!
Materials:
-  Ruler
-  Marshmallow
-  Scissors
-  Pipe Cleaner
-  Single hole
-  Plastic Cap
punch
-  Pushpin
-  Cold temp glue
-  Rectangular
gun or glue dots
tissue Box
-  Tape
-  Rubber Bands
-  Unsharpened
(2)
pencils (2)
Instructions:
1. Prepare: Expand the opening of your tissue box. To do this, place a ruler on top of
the box so that one edge is aligned with the box’s width. Trace a line along the
other edge of the ruler and then repeat this step on the opposite side of the box.
Connect these two lines to form a rectangle and then use your scissors to cut out
this piece.
2. Hole Punch: Next, use your ruler to mark a point on the
flank of your tissue box. This spot should be 2 inches in
from the width and ½ inch down from the top.
Repeat this process on the opposite side and then
punch holes at these locations.
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5.6D: Experimenting with Forces
Force, Motion, and Energy
Instructions (continued):
3. Make Hole: Next, use your pushpin to make a small hole in the far end of the
box. This point should be ¼ inch from the bottom.
4. Assemble: Find your unsharpened pencils and form an cross. Make sure that the
horizontal pencil crosses the vertical pencil at a height of around 2 inches. Next,
make a cut in one of your rubber bands and use the resulting rubber strip to bind
your pencils together. Make sure that this knot is secure so that the pencils stay in
place.
When your pencils are firmly
attached, ask an adult helper to use
hot glue to attach the cap to the
pencil end. Position the cap on the
vertical pencil, somewhere slightly
below the eraser and leave your
cross and cap to dry.
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5.6D: Experimenting with Forces
Force, Motion, and Energy
Instructions (continued):
5. Set Up: Once the glue has dried and the cap is securely attached, insert the
horizontal ends of the pencil cross into the holes on the sides of your box.
Next, loop the second rubber band around the bottom
of the vertical pencil. Fold your pipe cleaner around
this rubber band and then insert both ends through
the small hole in the back of the box. You may have
to enlarge this hole with the tip of a pen before the
ends of the pipe cleaner will fit. When they do, pull
them through the hole so that the rubber band is
being stretched and then tape them to the back of
the box like this:
Your catapult is now complete! Find a marshmallow and test your creation!
To do this, simply load a marshmallow into the cap, pull the pencil back, and let
go!
Does your catapult work? Describe the motion that the marshmallow takes. Does
it travel in a straight line? How far does it go? Can you predict where the
marshmallow will land? Is this motion consistent? Once it is in the air, what is
preventing the
marshmallow from traveling farther?
Can you identify the different forces at work? Try switching up the variables! What
happens when you pull the arm of your catapult back only half as far? What if you
were to use something lighter than a marshmallow? What if you were to use
something heavier? Remember that your catapult is homemade and thus relatively
fragile, but don’t let this stop you from conducting further experiments!
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5.6D: Experimenting with Forces
Force, Motion, and Energy
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