Materials
What things are made of, and why that choice was made. 4 reviewed articles here, each naming the sources behind it.
What materials covers here
What things are made of, and why that choice was made. These are the questions a general reference work tends not to answer well — comparisons, causes, and the distinctions people routinely conflate.
Every one of these was read by a person
An article appears in this list only once somebody has checked it against its sources. Drafts and short articles are readable but are kept out of search and out of this list.
- What is the difference between glass and crystal? — In everyday language "crystal" means glass containing a metal oxide — historically lead — which raises its ref…
- What makes stainless steel stainless? — Chromium. At around 11% or more, chromium in the alloy reacts with oxygen to form an extremely thin, transpare…
- Why do old books smell like that? — The smell is the paper decomposing: lignin and cellulose slowly break down and release hundreds of volatile or…
- Why do lithium batteries lose capacity over time? — Mostly because a passivating layer keeps growing on the negative electrode and permanently consumes lithium — …
Questions
What is the difference between glass and crystal?
In everyday language "crystal" means glass containing a metal oxide — historically lead — which raises its refractive index and makes it sparkle; in materials science the two words describe opposite kinds of atomic order, and ordinary glass is not a crystal at all.
What makes stainless steel stainless?
Chromium. At around 11% or more, chromium in the alloy reacts with oxygen to form an extremely thin, transparent, self-repairing oxide layer that seals the surface — so stainless steel does not resist corrosion by being inert, it resists it by corroding instantly and then stopping.
Why do old books smell like that?
The smell is the paper decomposing: lignin and cellulose slowly break down and release hundreds of volatile organic compounds, including vanillin, benzaldehyde and organic acids, which is why old paper genuinely does smell faintly of vanilla and almonds.