Meta Material types
Everything we make is made up of one or more materials. Different materials have different properties. Because of these different properties, they can be used to make many kinds of objects. Materials can be soft or hard. They can be flexible or stiff. They can be delicate or very strong. You can distinguish the following meta material types:
Metal
Metals are some of the most important materials used in manufacturing and building. Some examples of metals are iron, aluminum, copper, zinc, tin, and lead. Many metals we use today are alloys. Alloys are made by combining two or more metals. They can also combine a metal with a nonmetal material. Alloys are made to give the metal new characteristics. Things like increased hardness or strength. For example, steel is an alloy of iron that contains a small amount of carbon.
Many metals are likely to corrode. Corrosion is a chemical reaction where metal reacts with oxygen. Sometimes this is good because it strengthens the metal. But when iron or steel react with oxygen, rust is created. Corrosion can eventually make metal break down entirely into rust.
Plastic
Plastics come in many different forms. They are used to make a wide variety of products. Plastic molecules are made up of long chains. These molecules are called polymers. Most plastics are either thermoplastics or thermoset plastics. Thermoplastics are heated and then moulded into shape. They can be reheated later and reshaped. Most plastic bottles are thermoplastic. Thermoset plastics can only be heated and shaped once. Thermoset plastics are used to make things like electrical insulation, dinner plates and automobile parts. Plastics can take a very long time to break down. Plastic bottles take about 450 years to break down. Plastic shopping bags can take as long as 10,000 years! This is why it is important to recycle plastics. Thermoplastics are recyclable, but thermoset plastics are not. When possible, it’s better to choose thermoplastics over thermoset plastics so the plastic can be given a new life after use.
Is Plastic a Polymer? All plastics are synthetic polymers, but not all polymers are plastic. Plastic is a specific type of polymer. Plastics are synthetic and do not occur naturally. The terms polymer and plastic are not the same. Plastic is a specific type of polymer comprised of a long chain of polymers. Polymers, on the other hand, are made up of uniform molecules that are smaller than plastic molecules.
Wood
Wood can be classified as either hardwood or softwood.
Hardwood comes from deciduous trees. These are trees that lose their leaves in the fall. Hardwood is usually used to make furniture and in construction projects that need to last for a long time. Examples of hardwoods are oak, maple, and walnut.
Softwood comes from coniferous trees. Coniferous, or evergreen trees, keep their needles all year round. Most timber, or wood that is prepared for construction, is made from softwood trees. Softwood is usually used in parts of buildings, like windows and doors. It is also used in some kinds of furniture. Examples of softwoods are pine, fir, and spruce.
Ceramic
Ceramics are often defined by what they’re not. They are nonmetallic and inorganic solids. This means they aren’t made of metal, wood, plastics, or rubber. They are made by baking clay, sand, and other natural materials at very high temperatures.
A few examples of ceramics are bricks, tiles, and concrete. Ceramic materials are used to make everything from the homes we live in to the pots we cook food in to dental implants for our teeth. It is even used to make the insulating tiles on space shuttles! Glass (see below) is also a ceramic.
Glass
Glass is one of the most versatile materials created by humans. Glass is made mostly of sand, which is made up of silicon dioxide. When sand is heated to a very high temperature (about 1700°C) it becomes a liquid. When it cools again, it undergoes a complete transformation and becomes a clear solid.
The glass we are most familiar with today is called soda-lime-silica-glass. It is made mostly of sand, but some other ingredients as well. Soda ash, which is made up of sodium carbonate, reduces the sand’s melting point. This means it doesn’t have to be heated to as high a temperature before it turns into a liquid. But soda ash also makes the glass water-soluble. This means it can dissolve in water! Limestone, or calcium carbonate, is added to stop this from happening.
Textile
The word textiles originally referred to woven fabrics. Now it usually refers to all fibres, yarns, and fabrics. Textiles can be made from natural materials like wool and cotton, or from synthetic materials like polyester. Textiles are used to make clothing, carpet, and many other products.
Textiles are made up of many tiny parts called fibres. Textile fibres must have specific properties in order to be spun into yarn or made directly into fabrics. They must be strong, flexible, elastic, and durable. Fibres with these properties can be made into yarns and fabrics with similar properties.
But not all fibres have the same properties. Some are warmer, some are more durable, some are softer or more comfortable. Sometimes it takes a mix of fibres to achieve the desired properties of a finished textile product!
Leather
Traditional leather is made from animal skins. Synthetic, or faux leather is manufactured. Leather is used to make everything from car seats to furniture to footballs to handbags. It is durable and has a natural finish. These properties are difficult to recreate with synthetic materials.
Faux leather is usually made of a mix of natural and synthetic fibres that are coated with a plastic polymer. This material mimics the properties of genuine leather. Like genuine leather, faux leather is soft to the touch and water-resistant. Although it is not as durable as traditional leather, faux leather is difficult to cut or tear. As a result, it’s often used to make furniture.
There are ethical concerns about traditional leather because it is an animal product. But because traditional leathers are made of a natural material, they can biodegrade, or break down naturally. Faux leather behaves more like plastic and takes a very long time to break down. Faux leather as a synthetic polymer (see plastics).
Paper and Boxboard
Paper is an important material that many people use every day. From reading newspapers to drawing pictures to wrapping presents, you probably don’t realize how often you use paper. Paper can also be used to make other materials, like cardboard.
Paper is made from a material called pulp. Pulp is made from wood fibres mixed with water. These fibres usually come from softwood trees like spruce and pine. To make paper, trees are cut up and the bark is removed. Then the wood is ground into tiny pieces and mixed with water to create pulp. The pulp is chemically treated then pressed flat and dried.
Cardboard is made up of several layers of paper combined. Corrugated cardboard is made up of two sheets of flat paper that have a third sheet of paper corrugated or bent to form a wave shape between them. The final product is stiff, strong, and very lightweight. This cardboard can be folded up and glued to create boxes or other packing materials.
Rubber
There are two main types of rubber: natural rubber and synthetic rubber. Natural rubber is made from latex, which is produced by plants. Synthetic rubber is made using a mix of chemicals. Synthetic rubber has many of the same characteristics as natural rubber. It can be used in tires, hoses, belts, flooring and more. Almost 99% of the world’s natural rubber is made from the latex of a plant called Hevea brasiliensis. This plant is commonly known as the rubber tree. Latex undergoes a number of different processes to be made into the versatile, springy material we think of as “rubber”. First, it is “chewed up”, then chemicals are added to it. Next, it is squeezed and stretched, and then cooked at about 140°C so that it holds its shape. The final product is strong, stretchy, elastic, durable, and waterproof. It can be used to make products ranging from pencil erasers to running shoes to wetsuits! Natural Rubber can also be defined as a natural polymer and Synthetic rubber as a synthetic polymer.
