"How Paper is Made" PPT Courseware

"How Paper is Made" PPT Courseware

test you!

1. Do you know which country invented paper first?

China

2. What are the four great inventions of ancient my country?

Papermaking, printing, gunpowder, compass.

Cai Lun invented a new technology for making paper using bark, hemp heads, rags, and old fishing nets as raw materials. He produced a large amount of light and cheap paper and promoted the spread and development of human science and culture. The paper produced under the supervision of Cai Lun is called "Cai Hou Paper".

1. Familiarity paper

What kinds of paper have you seen and what are their uses?

2. How to make paper

What materials are needed to make paper? How is paper made?

How is paper made?

Paper is made from raw materials such as old hemp, tree bark, rattan, bamboo, straw, wheat straw, etc., processed into pulp, and then the pulp is processed into paper.

① Peel off the bark → ② Cut the wood into small pieces → ③ Boil the wood chips into pulp → ④ Stir the pulp → ⑤ Bleaching the pulp → ⑥ Drain the water → ⑦ Dry the water and press it into paper

Modern papermaking technology

Step 1: Collect raw materials

Step 2: Soak in brine

Step 3: Cross the pool

Step 4: Get the fiber

Step 5: Dry

Step 6: Finish the paper

The main raw material for papermaking is wood, and consuming paper actually consumes forest resources. At present, the total annual global demand for paper is 325 million tons, and the per capita paper consumption is 52 kilograms. On average, much of the 4,000 square kilometers of forest wood that disappears every year on the earth is used for papermaking.

Relevant data shows that to make 1 ton of paper, 17 large trees need to be cut down, and a large amount of wastewater is discharged during the papermaking process, polluting rivers and causing serious damage to the environment.

In order to reduce the consumption of forest resources and damage to nature, people use waste paper as raw materials to produce recycled paper. We can simulate the production process of recycled paper and make a piece of "recycled paper" ourselves.

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