Material Properties of a Catapult
Summary
Course Title: Shop/CTE Course (wood, metal, auto, machine, drafting)
Project Author’s Name: Scott Seacrist, slseacrist@gmail.com
Brief Project Description: (1) Students will learn about the evolution of catapult design,
(2) understand the properties of common materials used in building the catapults used
in class, and (3) apply knowledge gained to determining appropriate usage in varying
environments and applications.
Materials and Equipment Required: worksheets, datasheets, handouts, piece of each
material (recommended), 8.5x11 paper, computer (optional), colored pens and pencils
Time for Lesson: Part 1 = 60 minutes. Part 2 = building the STEM catapult. Part 3 = 60
minutes.
Links & Resources: See attachments. Fun, optional video here. This is a good
properties page and Wikipedia has useful information. MatWeb is a good resource for
specific properties of specific materials.
Teaching
Objective: Linking the evolution of catapult design to the need to choose materials
appropriate to specific environments and applications based on their properties.
Student Standards of Performance: n/a
“Hook” or Anticipatory Set:
1. Discuss catapult design over time (fun, optional video here).
2. Form groups to report on materials properties.
3. Build catapult.
4. Determine properties of specific materials and make appropriate changes
depending on environment and application.
Modeling/Examples: n/a
Guided Practice:
1. Discuss catapult design over time (fun, optional video here). The point is to show
the evolution in catapult design and how designers adapted designs to meet
specific needs.
Resources needed: Catapult Design handout (see attachment).
2. Discuss the different properties of materials, including density, corrosion, tensile
strength, heat resistance/melting point, machinability/cutting speed, magnetism,
and cost.
Materials needed: piece of each material (recommended).
3. Have students gather into teams. These are the teams they will be on for building
the catapult.
4. After dividing into teams, each team member will be assigned one of the
following: density, corrosion, tensile strength, heat resistance/melting point,
machinability/cutting speed, magnetism, and cost. Their activity will be to
produce an information sheet that should include a the general definition of the
property, specific data/information about that property for each of the materials in
the catapult, a graphic depicting their property, and a bar graph comparing the
materials.
For this project, the students need to research the following materials:
 American Pine Wood
 Aluminum 6063-T4
 AISI Type 304HN Stainless Steel
 Titanium Ti-6Al-4V ELI (Grade 23) Annealed
 UNS C36000 Brass
 Quadrant EPP Proteus® White Homopolymer Polypropylene (plastic)
Resources/materials needed: computer (optional), datasheets/textbook/resource
with information on the various materials and their properties, 8.5x11 paper,
colored pens and pencils. This is a good properties page and Wikipedia has
useful information. MatWeb is a good resource for specific properties of specific
materials.
5. After finishing their information sheet, each team member will report his or her
findings to their team.
6. Each team builds its own catapult (approximate time=3 hours).
7. Now that each team member has property information for each of the materials in
the catapult and the teams have actually built the catapult using the various
materials, they will consider various scenarios and recommend changes to their
catapult depending on the needs of the environment and/or application.
Resources/materials needed: “The Catapult Diaries” worksheet (see attachment).
Checking for Understanding: See “The Catapult Diaries” worksheet.
Closure: Have each group report out on their finding from “The Catapult Diaries”
worksheet.
Post-Project Independent Practice: n/a
Careers
Material Science
Engineering
Manufacturing Engineering
Artist
Wielder/Fabricator
Mechanic