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On Track Learning

Lesson 4: Material Resiliency (Science)


Lab: The students will be expected to test their hypothesis of which fabric will be the most suitable for a safety harness

Student expectation: In teams, students will prepare a pattern 2 inches wide by 18 inches long. Select fabrics for testing. Pin and cut to the pattern. The students will measure the initial length as well as length following the addition of one-half gallon of water and one gallon of water. Care should be taken to also measure the length after removal of each weight treatment. The students will be expected to compare their data with other groups and prepare a report that will illustrate their findings and conclusions.

Hints: Students may bring in old clothes or blankets. The key is the strips of fabric need to be consistent. Creating a 2 inch by 18 inch pattern of cardstock for each group would increase consistency. Students will need 2 strips of three different fabrics. (6 strips in total). Fabric remnants from this experiment may be used in the flame retardancy lab.

Student Worksheets

Name ________________ Materials Resiliency Lab

Names of others in your group ________________________

Write down a description of each piece of fabric:

Read through the procedure. Before conducting the lab, hypothesize what will happen to each of the pieces of fabric. Compare your prediction with the predictions of the other members of your group.


  1. 1) Cut 2 strips of 3 different fabrics. Each strip needs to be 2” x 18”. Use a template to be sure all pieces are the same size. Precise cutting is important for this lab.
  2. 2) Set up the 20” 1 x 4 piece of wood. Move two desks close enough and place the piece of wood so an end is on each desk. The fabric will be clamped onto this piece of wood.
  3. 3) Fill the half-gallon jug with water. Select one piece of fabric. Loop the fabric through the handle of the jug. Clamp the ends of the fabric onto the piece of wood.
  4. 4) Use the string to measure the stretched fabric. Before removing the clamps and the jug, take the piece of string and mark the length of the fabric on the string. Use the yardstick to measure that length. Record results.
  5. 5) Take the second strip. Fill the gallon jug with water. Repeat the steps. Record results.
  6. 6) Continue these same steps for the two remaining fabrics.

Fabric 1

Fabric 2

Fabric 3

½ gallon measurement:


1 gallon


Compare the actual results with your earlier predictions.


Name ___Teacher Edition________ Quiz – Materials Resiliency Lab

1) In selecting materials for seat belts, list two pieces of information you learned during the lab that would help you better select safe materials.

Possible answers:

  1. Whichever fabric had the greatest stretch (flannel, knit) would have stretched too much. If seat belts stretch too much, the person will fly forward.
  2. An item that stretches too little can also be dangerous to the body in an accident causing injury where it comes in contact with the body.)

2) If you were assigned to create the cord for an amusement park bungee jump, what are two components of the bungee cord that would be important for rider safety?

(Possible answers: )

  • Stretch so there isn’t a sudden stop for the rider
  • Strength so that the cord doesn’t snap and break<
  • Quantity of stretch so rider doesn’t hit the ground

That the stretch of the cord doesn’t increase with repetitive use so rider doesn’t hit the ground)

Name _______________________ Quiz – Materials Resiliency Lab

  1. In selecting materials for seat belts, list two pieces of information you learned during the lab that would help you better select safe materials.
  2. If you were assigned to create the cord for an amusement park bungee jump, what are two components of the bungee cord that would be important for rider safety?

Standard Course of Study Objectives

  • Goal 1 The learner will design and conduct investigations to demonstrate an understanding of scientific inquiry.
  • 2.03 Evaluate technological designs for application of scientific principles.
  • Risk and benefits, constraints of design and consistent testing protocols.

Science Background information
Interviewer: Stretch vs. resiliency – what is the difference?

Rolin: Stretch is the elongation of something when you pull on it, resiliency is how well it returns to its pre-stretched shape. They are two different properties; a rubber band stretches and is resilient and taffy also stretches but is not resilient. Steel doesn’t stretch much but is fairly resilient and so on …

Interviewer: Besides the material, what other things affect stretch and resiliency?

Rolin: How the material is used is important. If it’s a cloth, is a knit or a weave? What sort of weave (plain, twill, satin …)? How fast is it pulled? Silly putty stretches if you pull slowly but it fractures if you pull it fast. Some materials return to their original shape (are resilient) very quickly, others take time. So geometry and loading rate are important when considering stretch and resiliency.

Interviewer: Do we want seat belts to stretch and be resilient?

Rolin: You want seatbelts to stretch some to soften the blow. In general they are not particularly resilient but this could be a problem during an accident with several impacts. In such a case the first impact is usually the worst and a lack of resiliency is not a major factor.

Interviewer: So what is ideal for a seatbelt?

Rolin: You want a seat belt to stop the person from striking the car’s interior. The properties we are most interested in are:

  • Appearance: Color, look and feel are important too
  • Geometry: It must fit the person and be wide enough to spread the blow
  • Stretch: Enough to cushion the blow
  • Resiliency: Enough to protect in a multiple impact accident
  • Appearance: Color, look and feel are important too

Interviewer: Thanks!


National Science Standards

  • All students should develop abilities necessary to do scientific inquiry and understandings about scientific inquiry.
  • All students should develop an understanding of properties and changes of properties in matter, motions and forces and transfer of energy.
  • All students should develop abilities of technological design and understandings about science and technology.
  • All students should develop understanding of science and technology in society.
Materials Need: 
  • Different kinds of fabrics
  • Gallon and half-gallon container with screw cap and a handle for each group
  • String (1 yard) for each group
  • Yardstick
  • Heavy duty spring clamps
  • 20” 1X4 piece of wood per group (to be placed between two desks)
  • Water Pins & newspaper for patterns
  • Sewing scissors
Supplemental Files: