Writing on Paper: Graphite & Adhesion Effects

In summary, when writing on paper with a pencil, the friction of the graphite against the paper causes the graphite to shear into small flakes, which become attached to the paper fibers and may be embedded in them. The graphite particles can be removed by erasing, with finer particles penetrating deeper into the paper surface. Some van der Waals forces may also be at play, but their impact is likely minimal.
  • #1
Manchot
473
4
I'm just curious: what happens when you write on a piece of paper with a pencil? Does the graphite actually penetrate the paper, or is it just on the surface? Also, what kind of adhesion occurs between the two materials? Thanks for your time.
 
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  • #2
Friction of drawing the graphite across the paper causes the graphite to shear in very thin flakes, which become attached to the paper fibers and perhaps embedded in the fibers or stick to the ceramic filler. The graphite particles are quire small.

They can be removed (erased) so they are at the surface with finer particles penetrating more deeply into pores in the paper surface.

The maybe some van der Waals forces at work, but the magnitude is probably small.
 
  • #3


When you write on a piece of paper with a pencil, the graphite does in fact penetrate the paper to some extent. This is because the graphite in pencils is made up of a mixture of clay and graphite particles, which are soft and can easily transfer onto the paper fibers. However, the amount of penetration depends on the pressure applied when writing and the type of paper being used.

As for the adhesion between the graphite and paper, it is mainly due to the physical interaction between the small particles of graphite and the fibers of the paper. The graphite particles get caught in the tiny crevices and pores of the paper, creating a strong bond. This adhesion is further enhanced by the pressure and friction of the pencil on the paper, which helps to push the particles deeper into the paper fibers.

Furthermore, the type of paper also plays a role in the adhesion between graphite and paper. Rougher papers with more texture will have a stronger adhesion compared to smoother papers. This is because the rougher surface provides more opportunities for the graphite particles to get trapped and adhere to the paper fibers.

In conclusion, writing with a pencil on paper involves both penetration and adhesion effects. The graphite particles do penetrate the paper to some extent, and the adhesion between the two materials is mainly due to the physical interaction between the particles and fibers. Next time you write on paper with a pencil, you can appreciate the science behind the simple act of writing.
 

1. How does graphite affect the writing quality on paper?

Graphite is a key component in traditional pencil lead, and it is responsible for the smoothness and darkness of the lines when writing on paper. The graphite particles easily adhere to the paper, leaving a consistent mark that is easy to read and erase.

2. What factors affect the adhesion of graphite to paper?

The quality and smoothness of the paper surface can affect the adhesion of graphite particles. Rough or textured paper may cause the graphite to skip or create uneven lines. The pressure and angle of the writing tool can also impact the adhesion, as well as the type and amount of graphite used.

3. How does humidity affect writing on paper with graphite?

Humidity can affect the adhesion of graphite particles to paper. In high humidity, the paper may absorb moisture and become softer, allowing the graphite to adhere more easily. However, in low humidity, the paper may become drier and more resistant to the graphite, resulting in lighter and less consistent lines.

4. Can the type of paper affect the graphite adhesion?

Yes, the type of paper can greatly affect the adhesion of graphite particles. For example, glossy or coated paper may repel the graphite, resulting in lighter and less consistent lines. On the other hand, rough or textured paper may cause the graphite to skip and create uneven lines.

5. How does pressure affect the adhesion of graphite to paper?

The amount of pressure applied when writing can impact the adhesion of graphite particles to paper. Applying too much pressure can cause the graphite to break or smudge, resulting in darker and thicker lines. On the other hand, using too little pressure may result in lighter and inconsistent lines.

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