Paper

Paper is a thin sheet.

It is made from tiny plant bits. People mix these bits with water to make a mush. This mush is called pulp.

Next, the water is squeezed out. Then the sheets are dried. This can be done with heat. Long ago, people hung sheets like laundry to dry.

Old paper was made from old cloth. Later, people learned to use wood. This made much more paper for everyone.

We can even use old paper to make new paper. This is called recycling. It is a great way to help.

Now you can use paper to write or draw!

Paper is a thin sheet made of tiny plant fibers.

These fibers come from plants like wood or hemp. To make paper, these fibers are turned into a wet mush called pulp.

There are different ways to make pulp. In chemical pulping, a liquid is used to cook the wood. This removes a part called lignin. Removing lignin makes the paper last longer. In mechanical pulping, machines grind the wood into fibers. This is cheaper, but the paper may turn yellow over time.

Once the pulp is ready, it goes to a paper machine. The machine spreads the pulp into a thin web. It then presses the sheet to squeeze out the water. Finally, heat dries the paper.

Some paper gets a coating to help ink stay in place.

We can also recycle paper. This means using old paper to make new pulp. We use water and machines to separate the fibers again. This helps us use our resources well. Today, paper is used for many things, like money.

Paper is a thin sheet made of matted fibers. These fibers are mostly made of cellulose.

Most paper comes from a material called lignocellulose. This material is turned into a wet mush called pulp. The pulp is then drained and dried into flat sheets. Different kinds of paper exist based on their density or size. People use many types for different jobs.

Making pulp is the first big step in the process. In chemical pulping, a cooking liquid dissolves the lignin. Lignin is a part of the wood that holds it together. Removing it helps the paper last a long time. This is how we make wood-free paper.

Mechanical pulping is another way to work. This uses machines to grind wood into fibers. It is cheaper but can make paper turn yellow. This happens because the lignin stays in the paper.

People have been making paper for a very long time. The oldest fragments of paper-like material come from China. These date back to the 2nd century BCE. A man named Cai Lun is credited with the pulp process. He lived during the Han dynasty around 105 CE. Later, paper spread to the Islamic world. By the 13th century, it reached medieval Europe. In Europe, people built the first water-powered paper mills.

Modern paper making changed a lot in the 1800s. In 1843, wood pulp was invented. This made pulpwood paper the most common kind. Two inventors worked on this around the same time. Charles Fenerty was from Canada. Friedrich Gottlob Keller was from Germany. They both found ways to pulp wood fibers. This helped make paper much cheaper for everyone to use.

Today, we use paper for many important things. We use it for books and even for money.

We can also recycle old paper to make new pulp. This involves breaking the bonds between fibers with water. We can use waste from mills or even old magazines. Some paper gets a special coating to help ink stay put. This is called sizing. It makes the paper better for printing.

Paper is a thin sheet made of matted cellulose fibers. Most paper is derived from lignocellulose, which is a material found in plants. The production process involves turning this material into a liquid pulp or slurry. This slurry is then drained and dried into flat sheets.

Paper comes in many varieties. These types are defined by their fiber content, pulp, sizing, coating, size, density, and grammage. Understanding how paper is made helps us see how a simple plant material becomes a tool for communication.

The manufacturing process begins with creating pulp. Pulp is a mixture of isolated fibers. There are two primary ways to make this: chemical pulping and mechanical pulping. In chemical pulping, a cooking liquor is used to dissolve the lignin. Lignin is the substance that holds wood fibers together. By dissolving it, the cellulose fibers are preserved and kept long.

This produces wood-free paper, which is more durable because it lacks the lignin that causes deterioration. There are three main chemical methods: the sulfite process, the kraft process, and soda pulping. The kraft process is the most common today. It is unique because the reaction with lignin produces heat. This heat can actually be used to run a generator for electricity.

Mechanical pulping is a different approach. In the thermomechanical pulp (TMP) process, wood chips are fed into steam-heated refiners. These machines squeeze the chips between steel discs to create fibers. Another method is groundwood pulp (GW). This involves feeding debarked logs into grinders that use rotating stones. Mechanical pulping is very efficient, with a yield of over 95 percent. However, it does not remove the lignin. Because the lignin remains, this type of paper tends to turn yellow and become brittle over time.

Once the pulp is ready, it moves to a paper machine. The pulp is fed onto the machine to form a paper web. Water is removed through a process called pressing. This uses force to squeeze the liquid out of the sheet. A special kind of felt is used to collect the water. After pressing, the paper must be dried. In the past, people hung sheets to dry like laundry. Modern machines use steam-heated can dryers. These machines use long sequences of more than forty heated cans. This process can dry the paper until it has less than six percent moisture.

After drying, the paper can undergo sizing and finishing. Sizing involves applying a thin layer of material to the surface. Common materials include kaolin or calcium carbonate. This coating changes how the paper feels and prevents ink from running. The surface can also be polished through burnishing or calendering.

Finally, the paper is either cut into sheets or wound onto large reels. Most machine-made paper is "woven," meaning it has a consistent density along the paper grain.

The history of paper is quite long. Archaeological evidence shows paper-like materials existed in China during the 2nd century BCE. The pulp process is often credited to Cai Lun, a Han court eunuch in 105 CE. While papyrus was used in ancient Egypt, it was different from paper. Papyrus is a lamination of plant fibers, while paper is made through maceration. Paper eventually spread to the Islamic world and then to Europe by the 13th century. In Europe, the first water-powered paper mills were eventually built.

Industrialization changed everything in the 19th century. Before this, most paper was "rag paper" made from discarded textiles. In 1843, the invention of wood pulp changed the industry. Two inventors, Charles Fenerty from Canada and Friedrich Gottlob Keller from Germany, independently developed wood pulping processes. This made pulpwood paper the dominant variety used today. This shift greatly reduced the cost of making paper for everyone.

Today, we also use recycling to manage paper waste. De-inking is a process used to remove printing inks from old paper. This was invented by Justus Claproth in 1774. We can recycle mill waste, preconsumer waste from factories, or postconsumer waste from homes. While recycled paper is useful, it is often not as bright or strong as paper made from virgin pulp. Despite the rise of digital technology, paper remains vital. It is used for everything from books to paper money.