Physics
GROUP MEMBER #1: ____________________________________
Ch. 4- Projectile Motion
GROUP MEMBER #2: ____________________________________
GROUP MEMBER #3: ____________________________________
MARSHMALLOW CATAPULT!
Objective: To apply your knowledge of two-dimensional motion to design a catapult that can
accurately launch a marshmallow and hit a designated target.
Requirements and Design Rules:
1. In this lab you will be building marshmallow catapults.
2. Your catapult must be able to launch a small marshmallow at any angle between 0° and 90°.
3. You may only use the materials provided.
4. The appearance of the catapult will not be judged, but you should pay careful attention to
design elements that affect the ability of your catapult to adjust to new distances.
5. There are several design ideas provided on the attached sheet. You may use one of these
designs or adapt one to guide your catapult design.
6. You will have 2 class periods to design and build the catapult (keep this in mind so that you can
work at home if necessary).
7. You must submit a Design Plan on the date of launch.
8. You will launch your marshmallow three times and record its displacement and air time in a
data table.
 For your measurements, launch FROM THE FLOOR. Measure from when the projectile
leaves the catapult on the floor, to when it first hits the floor. This probably works best
out in the hallway so your marshmallow does not hit any targets before making it to the
floor.
 The group with the highest average displacement will get extra credit on the Ch. 4 test.
9. Your final grade will be determined by:
 Design Plan
 Data Table
 Conclusion questions
 Group collaboration score
Materials:
 Popsicle sticks
 Glue gun
 Rubber bands
 Plastic spoon



Paper
Tape
Timer
Resources:
http://www.stormthecastle.com/catapult/how-to-build-a-catapult.htm
http://www.knightforhire.com/catapult.htm
Your Design Plan Must Include:
1) A list of materials to be used (should be bulleted). (2 pts)
2) A neat hand-drawn diagram of your catapult with labeled parts. (5 pts)
3) A diagram of the expected trajectory of the marshmallow with labeled vectors/components (xi,
xf, yi, yf, vi, vxi, vyi, vf, vxf, vyf). (half point per label = 5 pts; trajectory shape = 1 pt)
Physics
GROUP MEMBER #1: ____________________________________
Ch. 4- Projectile Motion
GROUP MEMBER #2: ____________________________________
GROUP MEMBER #3: ____________________________________
MARSHMALLOW CATAPULT!
Design Plan
_________
40
List of materials we used:
Materials:
/1
Diagram with labels:
/5
Trajectory with Labeled Vectors & Labeled Components:
/6
Data Table (4 pts) Use and include SI units.
Displacement (m)
Launch 1
Time (s)
Launch 2
Launch 3
Average
Conclusion Questions: (For calculations, show equation used and include work with units.)
1. How does changing the angle affect the projectile’s range? The initial velocity? (no calculation)
(2 pts)
2. What are some limitations of your physical model? (no calculation) (1 pt)
3. How much time did the marshmallow spend GOING UP? (2 pts)
4. What was the initial horizontal velocity of the projectile as it left the catapult? (3 pts)
5. What was the initial vertical velocity of the projectile as it left the catapult? (3 pts)
6. How high did it go? (3 pts)
7. Calculate the resultant initial speed of your projectile. (3 pts)
8. What was the resultant direction (angle) of your projectile? (3 pts)
9. What was the horizontal acceleration after the projectile was fired? (no calculation) (1 pt)
10. What was the vertical acceleration after the projectile was fired? (no calculation) (1 pt)
11. What was the horizontal speed at the top of the trajectory? (no calculation) (1 pt)
12. What was the vertical speed at the top of the trajectory? (no calculation) (1 pt)
Collaborative Work Skills Peer Review
EVALUATOR’S NAME:
CATEGORY
________________________________________
PERIOD: ______
4
3
Contributions
Routinely provides useful
ideas when participating in
the group and in
classroom discussion. A
definite leader who
contributes a lot of effort.
Usually provides useful
ideas when participating in
the group and in
classroom discussion. A
strong group member who
tries hard!
Sometimes provides
useful ideas when
participating in the group
and in classroom
discussion. A satisfactory
group member who does
what is required.
Rarely provides useful
ideas when participating in
the group and in
classroom discussion. May
refuse to participate.
Quality of Work
Provides work of the
highest quality.
Provides high quality
work.
Provides work that
occasionally needs to be
checked/redone by other
group members to ensure
quality.
Provides work that usually
needs to be
checked/redone by others
to ensure quality.
Time-management Routinely uses time well
throughout the project to
ensure things get done on
time. Group does not have
to adjust deadlines or
work responsibilities
because of this person's
procrastination.
Usually uses time well
throughout the project, but
may have procrastinated
on one thing. Group does
not have to adjust
deadlines or work
responsibilities because of
this person's
procrastination.
Tends to procrastinate, but
always gets things done by
the deadlines. Group does
not have to adjust
deadlines or work
responsibilities because of
this person's
procrastination.
Rarely gets things done by
the deadlines AND group
has to adjust deadlines or
work responsibilities
because of this person's
inadequate time
management.
Cooperation
Usually listens to, shares,
with, and supports the
efforts of others. Does not
cause "waves" in the
group.
Often listens to, shares
with, and supports the
efforts of others, but
sometimes is not a good
team member.
Rarely listens to, shares
with, and supports the
efforts of others. Often is
not a good team player.
Almost always listens to,
shares with, and supports
the efforts of others. Tries
to keep people working
well together.
2
1
Group Member’s Name: _______________________________
Contributions + Quality + Time Mgmt. + Cooperation
Score:
________ + ________ + ________ + ________
=
TOTAL:
=
_____________
=
TOTAL:
=
_____________
=
TOTAL:
=
_____________
Group Member’s Name: _______________________________
Contributions + Quality + Time Mgmt. + Cooperation
Score:
________ + ________ + ________ + ________
Group Member’s Name: _______________________________
Contributions + Quality + Time Mgmt. + Cooperation
Score:
________ + ________ + ________ + ________