Do Paper Contracts When Burnt?

  • Context: High School 
  • Thread starter Thread starter ajayraho
  • Start date Start date
  • Tags Tags
    Paper
Click For Summary

Discussion Overview

The discussion revolves around the phenomenon of paper contracting when burnt, particularly focusing on newspaper. Participants explore the physical changes that occur during combustion, including mass loss and changes in volume, as well as the effects of chemical treatments on paper over time.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants observe that when newspaper is burnt, the writings appear smaller, prompting questions about whether the paper itself contracts.
  • One participant notes that burning paper turns it to ash, suggesting a complete transformation rather than mere contraction.
  • Another participant supports the idea of contraction, explaining that water in the paper is driven off by heat, which could contribute to a decrease in volume, although the extent of this change may vary based on the paper's composition.
  • There is a mention of carbon compounds being converted into gases during combustion, leading to a loss of mass in the paper.
  • One participant raises a question about the yellowing of paper over time, linking it to chemical bleaching processes and subsequent reactions that may alter the paper's color.

Areas of Agreement / Disagreement

Participants generally agree that burning paper leads to changes in mass and volume, but there is no consensus on the specifics of how much contraction occurs or the implications of these changes. The discussion also introduces a separate topic regarding the yellowing of paper, which remains unresolved.

Contextual Notes

Some assumptions about the composition of paper and the effects of burning are not fully explored, and the discussion does not clarify the exact mechanisms behind the observed phenomena.

ajayraho
Messages
6
Reaction score
0
I have observed many times, that when a newspaper is burnt, its writings become smaller.

Do the paper really contract when burnt?
 
Physics news on Phys.org
ajayraho said:
I have observed many times, that when a newspaper is burnt, its writings become smaller.

Do the paper really contract when burnt?
It's not clear what you are describing.

When I burn a newspaper, it turns to ash.
 
Hello Ajayraho,
I think your observation has credence.
The paper would have to get smaller and smaller as it burns.

For one thing all the water in the paper is driven off by the heat. The percentage change in volume night not be all that much, depending upon the makeup of the paper.
Next the carbon compounds are turned into gases that can burn with the oxygen in the air. So the paper itself is actually losing mass.

If you don't disturb the ash remaining, you can still sometimes read the now smaller print, at least where it hasn't curled up on itself.
 
  • Like
Likes   Reactions: ajayraho, sophiecentaur and davenn
the paper itself actually loosing massmoreove moreover there were water before in the paper and vaporized after burnt the peper. However paper are not pure elements so the VDW between particle actually maintain constant but number of particle decrease so the paper contracts.
 
256bits said:
Hello Ajayraho,
I think your observation has credence.
The paper would have to get smaller and smaller as it burns.

For one thing all the water in the paper is driven off by the heat. The percentage change in volume night not be all that much, depending upon the makeup of the paper.
Next the carbon compounds are turned into gases that can burn with the oxygen in the air. So the paper itself is actually losing mass.

If you don't disturb the ash remaining, you can still sometimes read the now smaller print, at least where it hasn't curled up on itself.
A very satisfying answer..
So what's the reason behind the yellowing of papers, when kept for a long period of time?
 
Hi Ajayraho
actually, paper are not white from the origanls. it is yellow, we use some chemical bleacher to bleach the paper, however, the chemical will left ln the paper and during a long time, the chemical on the paper will reacts with paper which give a yellow colour on the paper
 

Similar threads

Graduate Feeling Burnt Out? Physics Degree Struggles and Advice
  • · Replies 8 ·
Replies
8
Views
2K
Graduate Using AI to evaluate white papers?
  • · Replies 42 ·
2
Replies
42
Views
3K
Shout out to my HS Science teacher from 10 years ago
  • · Replies 2 ·
Replies
2
Views
2K
Graduate Is ChatGPT useful yet for answering astronomy questions?
  • · Replies 21 ·
Replies
21
Views
4K
Studying Methods to improve my skills in studying papers
  • · Replies 2 ·
Replies
2
Views
2K
High School Thought Experiment: Behavior of shadow of object moving at speed c
  • · Replies 14 ·
Replies
14
Views
2K
How Can I Determine the Number of Poles in a Burnt AC Induction Motor?
  • · Replies 2 ·
Replies
2
Views
2K
High School Is a scientific paper a theory or discovery? Or only a paper?
  • · Replies 18 ·
Replies
18
Views
3K
High School Is Nuclear Energy Beneficial for the Future?
  • · Replies 2 ·
Replies
2
Views
1K
Graduate Correcting units from this physics paper?
  • · Replies 1 ·
Replies
1
Views
2K