Creative problem solvers continually seek inexpensive materials they can use in creative ways. Among those materials is paper, although of course paper can also be quite expensive, depending on the variety. Paper comes in many types, among them cardboard, whose properties were described in an earlier post (A Lesson from Cardboard). In Destination ImagiNation®, students use cardboard boxes and cardboard tubes, paper plates and paper cups, milk cartons and egg cartons, newspapers, freezer paper, wax paper, filter paper, toilet paper, tissue paper, paper napkins and paper towels, construction paper, wrapping paper, paper bags, card stock and plain sheets of copy paper. You can even make a paste from paper called papier mâché. The list is endless. How students are able to use paper products in their creative efforts is greatly determined by the properties of paper itself, so let’s take a look at those properties, and learn a little bit about how paper is manufactured.
A sheet of paper generally begins in nature, where the raw materials are harvested. The trees of the forest, including soft woods such as pine and spruce, or hard woods such as eucalyptus, acacia, albizzia and wattle, are chopped down and “chipped” into smaller, more manageable pieces. Farm fields that produce rice, wheat and straw are sources of paper pulp. Cotton fields supply seed hair for cotton linter used in paper making, and flax fields contribute to the making of linen paper from the bast tissue of the flax stem. Did you know that the spinning of rope, twine and cord produces a hemp waste product that is also used in paper making? Manila fibers used for manila file folders and envelopes come from plantain grown in the Philippine Islands. Recycling of waste paper products plays a role in paper making, too; about 80 percent of waste paper is used to manufacture paper boards (such as chipboard found in books or notebooks).
After raw materials are harvested, they go through the pulp making process. A cooking process removes lignin (used to bind wood fibers together) and other impurities, and then a special liquor is added to the chip batch under pressure. The chips are washed and cooked, and waste products are removed. Then the pulp undergoes bleaching, which produces the white appearance of many papers we use. Additives such as talcum and calcium carbonate make the paper brighter, while dyes add color and starch is a binding agent. Other additives include titanium dioxide, barium sulphate and zinc sulphide. Once the additive process is finished, the paper pulp is run through a wire mesh called a fourdriner, which removes most of the water. A roller applies pressure to the pulp to smooth it out. The paper product is transferred to a felt blanket that moves it through steam-heated dryers, removing any remaining moisture. A glaze-like coating is added, and then the paper passes through calendar stacks, a type of polished iron rolling system in which the rollers are stacked one on top of the other. This process does the final smoothing of the paper before it is wound on metal or fiber cores. The paper is then cut into sheets, packed and tested.
During the manufacturing process, various properties are built into paper that affect its appearance and use. These include basis weight; brightness, whiteness and color; bulk; dimensional stability; folding endurance; formation; gloss; machine and cross direction; moisture; opacity; porosity; sizing; smoothness; stiffness; stretch; tearing resistance; temperature and humidity (conditioning); thickness; surface strength, and the wire side and felt side. Obviously, this post is not designed to make you a technical expert about all of these factors, but an awareness of some of these terms will serve Destination ImagiNation® teams well when choosing the types of paper they wish to manipulate.
Basis weight. All sheets of paper have a basis weight, or weight per unit area. The higher the basis weight, the heavier the paper. Moisture content affects paper weight. What happens to paper when it becomes wet? What are the advantages of using 20-lb paper (copy paper) to 80-lb paper (card stock)? What are the disadvantages?
Bulk. Bulk refers to how thick a piece of paper is in relationship to its weight. When you decrease the bulk of paper, you increase its density, or its weight per unit volume. An increase in density means the paper gets glossier, smoother, less opaque (more light shines through), darker, and lower in strength. What are some thicker paper products? What are some thinner ones?
Dimensional stability. Dimensional stability refers to how much or little the size of a sheet of paper changes when it is exposed to moisture. Did you know that all papers expand or contract, depending on the amount of moisture to which they are exposed? Did you know that the rate at which paper expands or contracts depends on the type of paper? Test this with different types of paper. What happens when you use cardboard or paper for your props and it rains? What happens if you use watercolors, acrylic paint, or latex paint on paper? What about glue?
Folding endurance. Folding endurance is the ability of paper to withstand being folded repeated times before it breaks down and tears. What are the advantages to folding thin paper versus thick paper? What are the disadvantages? How can you use paper folding in Destination ImagiNation®? What could you make? (Hint: Visit your local library’s juvenile section and check out books similar to The Usborne Book of Papercraft, or The Michaels Book of Paper Crafts.) How do you think folding endurance is related to two other properties of paper, stiffness and stretch? What are the advantages (and disadvantages) of crumpling a piece of paper?
Machine and cross direction. The way that paper travels through the machine during the manufacturing process creates what is called a machine direction, or grain. The cross direction, or cross grain, is at right angles to the machine direction. When you fold paper or try to curve it in one direction, it is usually easier to fold parallel to the grain. Try this with different types of paper. You will encounter a little more resistance when you fold cross-grain. Is it easier to fold an index card the long way or the short way? What about a newspaper sheet? A sheet of copy paper?
Opacity. Opacity refers to how much light passes through a sheet of paper. The higher the opacity, the less light shines through. How could you use the opacity of paper in Destination ImagiNation®? What items could you make from paper that use this property?
Porosity. Porosity refers to how much moisture or air can pass through the individual fibers of the paper. This is extremely important to how the paper is used. The more porous paper is, the more moisture or air can pass through it. Try blowing air or pouring water through various types of papers, such as a paper towel, a glossy magazine page, a coffee filter and an ordinary sheet of copy paper. What happens? How can you make paper less porous? How can you use this paper property in Destination ImagiNation®?
Stiffness. Stiffness is the amount of force required to bend paper at a specific angle. It is affected by the thickness of paper, but also by how paper is shaped. Try this experiment with equal-sized sheets of copy paper and card stock. Build a vertical structure in the highest direction possible in these shapes: a tube, a triangle, and a square. (You can use a single piece of tape to secure the edges.) Then, balance a book on top of each structure. What happens? Try this experiment again, but this time fold a sheet of copy paper like an accordion, and do the same with a sheet of card stock. What happens this time? Does the height of the accordion folds make a difference?
Stretch. Stretch is the amount of distortion that paper goes through when it is affected by stress. Usually, that means that paper tears or ruptures when it is affected by too much stress (such as weight or pressure). Stretch is higher in the cross direction than the machine direction, but it is also affected by the type of paper used. What uses of paper in industry can you imagine where stretch would be important to think about?
Tearing resistance. Tearing resistance refers to how paper behaves when it encounters resistance, whether it tears or not. Earlier, we discussed how folding a piece of paper is easier when you fold with the grain instead of against it. What happens when you try to tear paper with the grain? Against the grain? What happens if the paper is damp and you try to tear it? Can you control it? Does the shape of a piece of paper affect its tearing resistance? (Cut different shapes, such as a rectangle or circle, and try to tear them.) What has greater tearing resistance—a paper towel, newspaper or index card?
As you explore creative ways to use paper for your Team Challenges, consider these questions in addition to the ones already asked:
- How many types of paper can you list?
- What are some recycled paper products you can use?
- Where can you buy paper products?
- How many ways can you think of changing the appearance of paper?
- How many ways can you think of reshaping paper?
- What new skills can you learn to manipulate paper?
- Learn how to make your own paper by using a resource book or a video. How would you use homemade paper in your Team Challenge?
- What are some paper crafting tools and adhesives that you would find handy? (Go to a craft or hobby store and explore the aisles.)
Post written by Judy Nolan, Co-Affiliate Training Director
“A to Z of Paper.” Ballapur Industries Limited. 2003, http://www.biltpaper.com.
Cusick, Dawn and Megan Kirby, eds. The Michaels Book of Paper Crafts. New York: Lark Books, 2005.
Fix, Alexandra. Reduce, Reuse, Recycle Paper. Chicago: Heinemann Library, 2008.
Perrins, Lesley. How Paper Is Made. New York: Facts on File-Threshold Books Limited, 1985.
Salvadori, Mario. The Art of Construction: Projects and Principles for Beginning Engineers & Architects. Chicago: Chicago Review Press, 1990.
Smith, Alastair, ed. The Usborne Book of Papercraft. Tulsa: EDC Publishing, 2001.