Classification Introduction
The pencil is a common writing and drawing tool made of materials such as wood, graphite and rubber. The history of the pencil can be traced back to the 16th century, and after hundreds of years of development, it has become an indispensable part of People's Daily life. There are many kinds of pencils, which are widely used and suitable for various occasions.
Features
1. Easy to erase: Pencil writing can be easily erased by eraser, easy to modify.
2. Rich line changes: By changing the degree of force of the pencil, you can draw different shades of lines, showing a rich sense of hierarchy.
3. Environmental protection: The main components of the pencil are graphite and wood, which is pollution-free to the environment.
4. Economical: Pencils are cheap, easy to use and suitable for mass consumption.
Application fields
1. Writing: The pencil is the common writing tool used by students and office workers, for taking notes, filling out forms, etc.
2. Painting: Pencil is the basic tool of painting, especially sketch and sketch, through the pencil can show the texture and three-dimensional sense of the object.
3. Design: When designers draw sketches, they often use pencils to outline and describe, which is convenient and fast.
4. Drawing: In engineering drawing, pencils are used to draw basic graphics and dimensioning.
5. Exams: Many exams allow pencil writing, such as multiple choice questions in math, physics, and other subjects.
Classification
1. According to the hardness classification: the hardness of pencils is divided into 9H, 8H, 7H, 6H, 5H, 4H, 3H, 2H, H, HB, B, 2B, 3B, 4B, 5B, 6B, 7B, 8B, 9B, etc., where H represents hard pencils and B represents soft pencils. The larger the number, the higher the hardness and the finer the pencil.
2. According to the material classification: pencil material has two kinds of wood pencil and plastic pencil, wood pencil texture is hard, feel better; Plastic pencils are soft and easy to carry.
3. According to the function classification: pencils have ordinary pencils, eraser pencils, mechanical pencils, etc. Eraser pencils and mechanical pencils have automatic rotation function, which is more convenient to use.
Shopping precautions
1. Choose a regular brand: When buying a pencil, you should choose a regular brand of pencil, and the quality is guaranteed.
2. Observe the packaging: The packaging of genuine pencils is clearly printed, the handwriting is eye-catching, and there are no mistakes and ambiguities.
3. Check the refill: Open the packaging of the pencil and check whether the refill is complete, without breakage and damage.
4. Trial experience: Before buying, you can try the pencil to feel whether its hardness and feel meet your needs.
5. Pay attention to preservation: After using the pencil, the nib should be placed downward to avoid breaking or moisture.
Conclusion
As a common writing and drawing tool, pencil has the characteristics of easy to erase, rich line changes, environmental protection and economic benefits. It is used in a wide range of fields, including writing, drawing, design, drawing and examination. Pencils can be divided into many types depending on their hardness, material and function. When choosing a pencil, you should pay attention to choosing a regular brand, observing the packaging, checking the refill, trying the experience and paying attention to preservation. In short, understanding the characteristics, application areas, classification and purchase precautions of pencils can help us better use and purchase pencils.