Making Stuff Stronger: Testing Tensile Strength

Our kits are currently being reviewed and updated by a team of collaborative, innovative and interdisciplinary educators who wish to enhance the educational opportunities for students. These dedicated teachers are members of CRISP Collaborative Science for All (CCSA) as well as local educators.

Click to see the SCSU CRISP Module Template used by CCSA for improving and updating the CRISP demos and kits. Each kit page offers a CRISP developed teacher module and CRISP aligned standards (both NGSS and CCSS)

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Test and compare the tensile strength and elasticity of polymeric materials: Kevlar®, Nylon, and cotton thread by lifting weighted buckets with wooden dowels. Learn that materials can be strong in different ways and that materials scientists test the strength of materials by stressing them to their breaking point.

Adapted from  Making Stuff  Stronger created by NOVA for Making Stuff

Subject(s):

Mechanics, Polymers, Properties of materials

Objectives:

  • Students will learn that materials can be strong in different ways (some will possess high tensile strength, some will be more elastic)
  • Students will understand that scientist test the strength of materials by stressing them to the point of breaking

Materials in this kit:

  • 4 identical 5 gallon buckets
  • 4 metal ‘S’ hooks
  • 4 wooden dowels
  • Cotton thread, size 35
  • Kevlar filament thread size 46
  • Nylon thread, size 46
  • Kevlar fabric swatches
  • Nylon fabric
  • Steel picture hanging wire, 28 gauge
  • Vinyl electric tape
  • Wire cutters
  • Bullet proof vest
  • NOVA Making Stuff Stronger Booklet

Teacher will need to provide a 24 case of water

Suggestions for the Teacher:

Students will have an understanding of the metric system, how to measure mass, how to write a procedure and how to graph before doing this lab. Definitions of the words strength,stress, tensile strength, elasticity, elongation and plastic are important as well.

Safety:

Please wear safety goggles

Additional Resources:

Stronger CRISP aligned standards
Breaking Point Testing Tensile Strength Teacher Module
Breaking-point-testing-tensile-strength-image from NOVA
Making Stuff Stronger demo_slides from NOVA
Breaking-point-tensile-strength-student-worksheet
Breaking-point-testing-tensile-strength-guide from NOVA

Making Stuff Website
NOVA website

STEM Careers:

Standards:

NGSS Performance Tasks:

MS-PS1-3 Matter and its Interactions
Gather and make sense of information to describe that synthetic materials come from natural resources and impact society.

HS-PS1-3 Matter and its Interactions
Plan and conduct an investigation to gather evidence to compare the structure of substances at the bulk scale to infer the strength of electrical forces between particles.

NGSS Disciplinary Core Ideas:

MS - PS1.A: Structure and Properties of Matter
Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms.
Solids may be formed from molecules, or they may be extended structures with repeating subunits (e.g., crystals).

HS-PS1.A: Structure and Properties of Matter
The structure and interactions of matter at the bulk scale are determined by electrical forces within and between atoms.

NGSS Cross-Cutting Concepts:

MS – CC 6 - Structure and Function
Structures can be designed to serve particular functions by taking into account properties of different materials, and how materials can be shaped and used.

HS CC1 - Patterns
Different patterns may be observed at each of the scales at which a system is studied and can provide evidence for causality in explanations of phenomena.

NGSS Science & Engineering Practices :

MS SEP 8 - Obtaining, Evaluating, and Communicating Information
Gather, read, and synthesize information from multiple appropriate sources and assess the credibility, accuracy, and possible bias of each publication and methods used, and describe how they are supported or now supported by evidence.

HS SEP 3 – Planning and Carrying out an investigation
Plan and conduct an investigation individually and collaboratively to produce data to serve as the basis for evidence, and in the design: decide on types, how much, and accuracy of data needed to produce reliable measurements and consider limitations on the precision of the data (e.g., number of trials, cost, risk, time), and refine the design accordingly.

Suggested Video(s):

http://www.pbs.org/wgbh/nova/tech/making-stuff.html#making-stuff-stronger