www.TeachEngineering.org: Free Curriculum for K-12

Massachusetts Science
- 2.2 Describe different ways in which a problem can be represented, e.g., sketches, diagrams, graphic organizers, and lists. (Grades 3 - 5) [2001]
- 1. Differentiate between properties of objects (e.g., size, shape, weight) and properties of materials (e.g., color, texture, hardness). (Grades 3 - 5) [2001]
- 1.1 Identify materials used to accomplish a design task based on a specific property, i.e., weight, strength, hardness, and flexibility. (Grades 3 - 5) [2001]

Does this curriculum meet my state's standards?

How to use a magnifying glass
The structure of fabric
Basic experimental testing skills

What do you think your clothes are made of? You, or a friend, can check the tags on your clothing to see if you are correct! How do you make your clothing choices? Do you go for fashion, function, or comfort? Does your choice of clothing change based on the activity you are doing? What would you wear if you were skateboarding, running, playing baseball, ice skating or reading a book? In today's activity you will be studying different types of natural and synthetic fabrics and their durability. Who knows, you may end up changing your choice of clothing!

Wear:	Damage, destruction, or marks of use by scraping or rubbing.
"Wear and tear":	The loss or damage that occurs to something in the course of normal use.
Breakthrough:	A sudden advance in knowledge or technique; point when a hole is created through a barrier.
Sandpaper:	Paper with rough material (like sand) fixed on one side and used for smoothing and polishing.
Magnifying glass:	A lens that magnifies objects viewed through it.
Fabric:	A woven or knitted material/cloth.
Weave:	Any pattern or method of weaving; to make on a loom by lacing together threads going lengthwise with threads going crosswise.
Thread:	A thin fine cord formed by spinning and twisting short fibers into a continuous strand.
Fiber:	A slender and long natural or synthetic unit of material (like wool, cotton, asbestos, gold, glass, or rayon) usually able to be spun into yarn.

Background

Summary of Natural Fibers:

Cotton comes from a cotton boll plant. Woven cloth made of cotton breathes freely, making it comfortable to wear in many kinds of weather. It can be sewn, woven, heated and pressed easily into flannel or used to make knit fabric. Linen is another type of natural fabric. Linen comes from a flax plant instead of a cotton ball plant. Linen wrinkles very easily, but is lightweight, for optimal use in hot weather. Silk is spun by silk worms and can be either smooth or rough. Finally, wool is made from animal hair.Fabric made of wool can provide tremendous warmth. Often, wool is combined with man-made fibers to make outdoor apparel for cold weather.

Summary of Synthetic Fibers:

Polyester is an example of a synthetic fiber used to make cloth. Polyester was popular when first introduced because of the ease of cleaning, durability and wrinkle-free appearance. However, unlike cotton, fiber made of pure polyester does not breath freely, trapping body heat and moisture, which can make it uncomfortable. Rayon is a more delicate fabric, but its soft draping quality can look like linen. Rayon is more absorbent than polyester, so it is more comfortable to wear. Another fabric, nylon, is often a part of many fabrics that stretch, like undergarments and swim suits. Acrylic is another material that can be made into fabric. Acrylic can be used as a wool substitute, since it is warm and does not wrinkle easily. Often, acrylic is found in winter outdoor apparel. For a more challenging activity, a discussion about the types of fabric and their various weave designs can be included.

Recommended Resources:

http://www.utexas.edu/centers/nfic/

Preparation

Obtain materials
Cut each fabric into 4 ¼" x 11" pieces.
Photocopy the "Fabric Wear and Tear" chart. (see link)

With Students

Part One: Observation

Put students in groups of two.
Give each group one piece of each type of fabric.
Have the students use a magnifying glass to look closely at each fabric.
Instruct each group to draw what each fabric weave looks like on the data sheet.

Part Two: Fabric Wear and Tear

Give each group a baseball or heavy ball.
Have each group wrap one of their pieces of fabric tightly around the ball and secure with a rubber band. (Note: The tighter the fabric is, the faster the experiment progress.)
Within each group, one partner should secure a piece of sandpaper (rough side up), while the other partner drags the ball across it. DO NOT PRESS DOWN on the ball, just let the weight of the ball drag once across the sandpaper.

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Student should use the magnifying glass to observe the area where the fabric was dragged across the sandpaper. Question for discussion: Was there any wear after just one scrape?
Have students continue to test the fabric one scrape at a time. After each successive scrape, examine the area with the magnifying glass, counting each scrape until you notice some wear on the fabric. Make a tick mark on the data sheet for each scrape.
When students notice some wear on the fabric, have them count and record the number of scrapes in the chart under "First Wear" for the tested fabric.
Have the students continue scraping the fabric and counting each scrape until they notice a hole or tear.
Record the number of scrapes in the chart under "Breakthrough" for that fabric.
Repeat steps 6 -12 for each of the other two fabrics.

What makes fabrics different?
Which fabrics are the strongest?
Why do certain parts of your clothes, such as the knees of pants or the elbows of shirts, wear faster than other parts?
Which fabric needed the most scrapes to show the first signs of wear?
Which fabric needed the least scrapes to show the first signs of wear?
Which fabric lasted the longest between the first signs of wear and the breakthrough point?
Which fabric qualities do you think were the most important for the durability of the fabric (e.g. type of fiber in the thread, strength of the thread, type or tightness of the weave)?