Targeting A Sweet Spot
45 Minute Lesson
NJ Standards
5.2.12.E.1 – The motion of an object can be described by its position and velocity as functions of time and by its average speed and average
acceleration during intervals of time.
5.1.12.D.2 – Science involves using language, both oral and written, as a tool for making thinking public.
5.1.12.D.1 – Science involves practicing productive social interactions with peers, such as partner talk, whole-group discussions, and small group
work.
NJ Standard
5.2.12.E.1
5.2.2.E.2
Goal
Students will be able to design a projectile launcher to launch short, mid and
long range projectiles.
5.1.12.D.1
5.1.12.D.2
Students will be able to discuss engineering design principles related to the
history and application of projectiles.
Resources
Student Use: Wooden Popsicle Sticks, Glue, Cardboard, Rubber bands, Cotton Balls, Spoons
Pre-Requisite Knowledge

Translational Kinematics
Evidence
Students will be able to construct a catapult
that can vary launching mechanism in order
to launch a projectile a far distance.
Students will be able to communicate about
the significance of projectiles as well as
contemporary and historical uses.
Real World Applications

Projectile Launchers Historical
Historical projectile launchers were commonly used in warfare as they were more powerful weapons. Arrows, cannons and other
weapons are some examples.

Projectile Launchers Contemporary
Machines have become more complex. Students should also be able to identify projectile launchers in our modern society including
machines and even sports. Baseball and tennis machines are pacifistic projectile launchers and there are other
Potential Difficulties

Students may not address realistic assumptions in building projectile launchers and may not be able to optimize launch angles for
maximum projectile range.

Students may have difficulties reinforcing their projectile launchers from self destruction upon launching.

Students with difficulties in 2-dimensional kinematics may have difficulties in determining the maximum range for a projectile.
Lesson Description
A. Opening (5 minutes)
In the Ice Age where it is important to live while hunting giant animals what tools are most practical? Have students brainstorm ancient
tools used for hunting.
[Students should determine that projectiles are the safest tools. Alternatively sharp tools are most useful for hunting, however close
range is not always practical]
B. Building a Catapult (15 minutes)
Students will divide into groups and build their own projectile launcher. The stipulations are that the catapult must be a multi-use
projectile launcher that can change projectile range. Have students identify the optimal configuration for maximum range theoretically
and then find the experimental optimal configuration. Students should note any changes to their design in order to increase their range.
C. History of Projectiles (15 minutes)
Have students in groups build a flowchart for the evolution of projectiles. It may start from a rock and end at a missile. After the
flowchart is produced, the class will convene and construct an all-encompassing flowchart. Groups will take turns identifying purposes
for improvements, physics principles, and actual engineering designs to further projectiles. Students may determine that projectile
engineering became much more complex over time if they consider hydraulics, steam powered devices, time release mechanisms etc.
Students may come to the conclusion that a majority of projectiles are weapons, encourage students to come up with projectiles that are
not weapons if there are too many weapons.
D. Reflection (10 minutes)
Students reflect on why projectiles were developed, the physics of projectiles, and how projectiles evolved over time.
Time Table
Activity
A – Opening
B – Building a Solar Catapult
C – History of Projectiles
Time Duration (Clock)
5 minutes
(0:05)
15 minutes
(0:20)
15 minutes
(0:35)
D – Reflection
10 minutes
(0:45)
Students doing
Discussion
Building and testing
Brainstorming, Presentation,
Discussion
Reflection
Teacher doing
Discussion
Presenting materials, Observing
Discussion
Discussion
Formative Assessment
What is the optimum angle for the maximum projectile range?
Theoretically, a 45 degree angle attains a maximum projectile range.
However, experimentally there are many assumptions that may make
this error prone.
Students may find that elastic potential energy principles can be used by
using rubber bands to build their launch mechanism. Alternatively,
rubber bands need not be used if the spoon is secured such that it can
be depressed.
Homework
Purpose
Students will take their catapult design
ideas and improve upon it theoretically
with materials they can find at home.
What materials will you use and how are
they expected to improve the range of
their design from class.
Students can think about using other
resources to engineer better devices. They
have to think about features of their
device that can be improved by changing
variables and identifying such variables.