Title:

Ski Technology and Composite Materials

Grade Level:

6,7,8,9

Subject:

Science

Author:

nbclearn

Lesson Plan Type:

Video,Interactive Instruction

Keywords:

composite materials, fiberglass, carbon fiber, polymer, flex strength, torsional rigidity

Brief Description:

Students will learn the basic engineering issues related to ski design. They will learn about composite materials and polymer materials. Also, students will create and test a composite material.

California State Standards Addressed:

Science/8/Investigation and Experimentation)8.0

Related Links:

Link 1:
Link 2:

Goal(s):

Students will learn about the role of composite materials and polymers in ski technology. Students improve their group work and communication skills as they build and test a composite material.

Specific Objectives:

Students will be able to:

1. Define composite material.
2. Define polymer.
3. List 2 uses of fiberglass.
4. List 2 uses of carbon fiber.
5. List 2 advantages of carbon fiber and fiberglass.
6. Describe the process of constructing a composite material.

Required Materials:

Quick Drying epoxy
String
Empty 1 gallon milk jug
Tape
Measuring cup
Water
Scale (range up to at least 10 lbs or 50 Newton’s)
Ruler
Two “2 by 4” pieces of wood about .75 m long (or
comparable materials)
Wax paper
String

Per group:
6 Pieces of 7cm x 16cm poster board
1 piece of fiberglass cloth 7cm x 16 cm
2 popsicle sticks

Anticipatory Set (Lead-in):

Raise your hand if you have:
Skied? Skateboarded? Surfed? Golfed? Played tennis? Used a laptop? Been on a boat? Used a portable toilet? (Use the toilet example at your discretion). What do all these things have in common? (Answer: they are all constructed out what we call “composite materials”.) Over the next two days we are going to learn about composite materials and also construct and test our own samples.

Lesson Plan Procedure:

Day 1 Part I (15 minutes)
1. Hand out the worksheet “Video Questions: Olympic Skis” and go over the questions with the class.
2. Show the NBC Learn Video: Olympic Skis and then go over the answers as a class.

Day 1 Part II (40 minutes)
Before class set up the testing area:
I. Position two table edges approximately 16 inches apart.
II. Lay the “2 by 4’s” across the gap, so that they are parallel to each other and 6 cm apart. Tape them down so they do not slide.

1. Once the testing area is set up, demonstrate and measure to the students the “maximum flex strength” of 1 piece of plane poster board, (defined as the weight needed to lower the jug 5 cm to the ground) and then 2 pieces together. Have the class record the weights in the “Student Data Worksheet.” The procedure for testing is:
I. Lay the sample across the supporting wood pieces.
II. Tie a loop of string so that it will go around the sample and support an empty water jug 5cm above the floor. (This 5 cm distance represents the maximum amount that the samples will be allowed to flex.)
III. Put on safety glasses before testing.
IV. Gradually fill the gallon jug until it touches the ground.
V. Weigh the jug and string to determine the relative flex strength of the sample.

2. Explain to the students that they are going to experiment making 2 types of composite samples. The first sample will be made with just 2 pieces of poster board and epoxy. The second sample will be made with 2 pieces of poster board, fiberglass cloth, and epoxy.
3. Explain the materials and the following procedures to the students, and depending upon the ability of the class, assist with the use of the epoxy. The procedure:
I. Wear rubber gloves and safety goggles.
II. Squirt a small amount of 2-part epoxy, about the diameter of a quarter, on the poster board. Use a popsicle stick to mix the epoxy well and then spread over the surface of the poster board.
III. Place the second piece of poster board over the glued surface.
IV. Place a book over the sample and allow to dry (place paper or wax paper over the sample to prevent it from bonding to the book).
V. Note: you will need to do this in a well-ventilated space, or outside, and have the students use safety goggles.
VI. The procedure for the second sample is essentially the same except that a piece of fiberglass cloth is laid over the spread out epoxy. Use the popsicle stick to immerse the fiberglass in the epoxy and eliminate as many of the air bubbles as possible before laying the 2nd piece of poster board over the fiberglass.
4. Have students clean up the area.
5. For homework, or if there is still time, they can describe the construction process on question #2 of the “Composite Material Activity Worksheet.”

Day 2
Caution: Students should wear goggles while performing or watching the sample tests.
1. Test the maximum flex strength of the student’s samples either as a class, or at different stations, and record results.
2. Have students work in groups to complete the activity worksheet, including the torsional strength test (this will yield only qualitative results).
3. Review the answers to the Composite Materials Activity Worksheet.

Closure (Reflect Anticipatory Set):

Ask the class why engineers and builders use composite materials. Challenge them to come back the next day with examples of things around them that are made from composite materials. (Not necessarily fiber based composites, but others such as concrete.)

Plan for Independent Practice:

For homework, or if there is still class time, students can complete the worksheet: General Questions about Composite Materials

Assessment Based on Objectives:

Quiz: Composite Materials

Possible Connections to Other Subjects:

Mathematics: Plot several point before the maximum flex weight is reached and then graph a force versus deflection curve, or explore the equation for flex strength.

Language Arts: Have students read article on the use and ethics of carbon fiber in sports (http://www.tms.org/pubs/journals/JOM/9702/Froes-9702.html) and either write an essay or have a structured debate.

Adaptations and Extensions:

More advanced students can explore the actual flex strength of the samples. In order to do this, they must measure the thickness of the different samples using calipers or a micrometer and the following formula:

Flex strength = (1.5 x load x span)/(width x thickness^2)

Where
Load = weight of water filled jug
Span = distance between 2 by 4’s (6 cm)
Width = width of sample (7 cm)
Thickness = thickness of samples as measured with caliper or micrometer

Additional Notes:

There are varying definitions for “composite material� including “a material that is made from more than one substance,� which would include non-fiber materials such as concrete. This lesson explores properties of fibrous composite materials.