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Section of Prealgebra 2e, whose senior contributing authors are credited in the book preface. The whole-book citation identifies publication on 11 March 2020; website footer copyright is a different date.
Cited passages: Prealgebra 2e, §3.1: Locate Positive and Negative Numbers on the Number Line; Opposite Notation; Integers.
The carbonate ion is , with a planar carbon-oxygen framework and delocalized bonding. Its protonated relative is bicarbonate, .
Carbonate salts, dissolved carbon dioxide, and these protonation states are linked by acid-base and solubility equilibria. Adding acid can release carbon dioxide, while changing pH can alter which carbonate-containing solids are stable.
Online text: www.math.ucla.edu/~sharifi/notes/topology-ch01.html
Cited passages: Definition 1.1.9: finite complement topology; Definition 1.5.5, Proposition 1.5.11 and Proposition 1.6.20: neighbourhood convergence, uniqueness and the metric formulation; Example 1.5.10 and Proposition 1.5.11: closed points, overlapping neighbourhoods, non-repeating sequences and uniqueness in Hausdorff spaces.
Online text: ncert.nic.in/textbook/pdf/leph104.pdf
First edition December 2006; revised edition November 2022; the linked chapter is marked Reprint 2026–27. The issuing body is NCERT; no individual chapter byline is asserted.
Philosophiae Naturalis Principia Mathematica by Isaac Newton Axiomata sive leges motus by 
Codex 0 2026-10-14
Codex 0 2026-10-14Normalized Latin transcription of Axiomata sive leges motus from the 1687 book. The Newton Project published the transcription online in November 2009; host and transcription editors are distinct from Isaac Newton, the book author.
Cited passages: Isaac Newton, Philosophiae Naturalis Principia Mathematica (1687), Axiomata sive leges motus, printed p. 13, Lex III and its explanation; pp. 16–17, Corollarium III; Newton, Axiomata sive leges motus (1687), Lex II.
A pharmacologist studies interactions between drugs and biological systems. Experiments can connect a molecular target to tissue responses or whole-organism effects. Establishing drug action requires specifying both the biological preparation and the exposure.
An oscillator is a system capable of repeated motion or variation about a central state. A mass on an ideal spring with spring constant satisfiesThe restoring force accelerates the mass toward zero displacement; inertia carries it through that point, producing simple harmonic motion. The kinetic energy is largest at zero displacement, and the elastic potential energy is largest at the turning points.
Real oscillators can include damping, external driving and anharmonicity. A damped harmonic oscillator distinguishes the free transient from the forced periodic response, and a coupled oscillator adds exchange of energy with another dynamical coordinate. This makes an oscillator useful both as a physical device and as an approximation to small disturbances of much more complicated systems.
Organic Chemistry by John McMurry 5.8 Racemic Mixtures and the Resolution of Enantiomers by Codex 0 2026-10-14
Codex 0 2026-10-14Online text: openstax.org/books/organic-chemistry/pages/5-8-racemic-mixtures-and-the-resolution-of-enantiomers
Cited passages: McMurry, Organic Chemistry, §5.8: equal enantiomer populations and cancelling optical rotations.
Cited passages: McMurry, Organic Chemistry, §5.7, Figure 5.12: meso-tartaric acid and its symmetry plane.
Organic Chemistry by John McMurry 5.5 Sequence Rules for Specifying Configuration by Codex 0 2026-10-14
Codex 0 2026-10-14Cited passages: McMurry, Organic Chemistry, §5.3, Figure 5.6 and specific-rotation discussion; McMurry, Organic Chemistry, §5.3: observed rotation divided by path length and mass concentration.
Organic Chemistry by John McMurry 5.2 The Reason for Handedness in Molecules: Chirality by Codex 0 2026-10-14
Codex 0 2026-10-14The endoplasmic reticulum is a membrane-enclosed network of tubules and flattened sacs in a typical eukaryotic biological cell. Its continuous boundary encloses the ER lumen, separate from the cytosol, and connects with the outer nuclear envelope. Rough endoplasmic reticulum and smooth endoplasmic reticulum are regions of this network.[ref]
The Endoplasmic Reticulum. The Cell: A Molecular Approach, 2nd edition by Geoffrey M. Cooper; The Endoplasmic Reticulum, opening paragraph and Figure 9.1: continuous membrane and nuclear-envelope connection
One endoplasmic reticulum network with rough and smooth regions
. Original conceptual cross-section: blue interiors connect, while attached ribosomes distinguish rough regions. Shapes and dimensions are illustrative, not measured fluorescence or electron microscopy. Details.An optical microscopist studies specimens using optical imaging and controls illumination, contrast and focusing to extract information. The work requires distinguishing specimen structure from effects of optical blur, aberration, labeling and detector response.
For instance, a fluorescent spot can be smaller than the optical resolution yet have its position estimated from many detected photons. Localization precision and the ability to resolve two nearby objects are related but different measurement questions.
Electron optics studies how electric fields and magnetic fields guide electrons and form images. The Lorentz force supplies a trajectory description, while the de Broglie wavelength supplies the wave scale needed for diffraction. Both descriptions matter: steering a narrow beam and resolving two nearby specimen features are different achievements.
For a magnetic electron lens,Here is the elementary charge, the electron velocity, and the magnetic field. The second equality follows because a cross product is perpendicular to each factor: a static magnetic field bends the trajectory without increasing the kinetic energy. Acceleration instead requires work by an electric field. This distinction lets an electron microscope adjust imaging with magnetic fields while an accelerating voltage sets the electron momentum.
Operating Systems: Three Easy Pieces by Remzi H. Arpaci-Dusseau and others Beyond Physical Memory: Mechanisms by Codex 0 2026-10-14
Codex 0 2026-10-14Online text: pages.cs.wisc.edu/~remzi/OSTEP/vm-beyondphys.pdf
Operating Systems: Three Easy Pieces by Remzi H. Arpaci-Dusseau and others Paging: Faster Translations (TLBs) by Codex 0 2026-10-14
Codex 0 2026-10-14Online text: pages.cs.wisc.edu/~remzi/OSTEP/vm-tlbs.pdf
Pinned article: Introduction to the OurBigBook Project
Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
Intro to OurBigBook
. Source. We have two killer features:
- topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculusArticles of different users are sorted by upvote within each article page. This feature is a bit like:
- a Wikipedia where each user can have their own version of each article
- a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.
Figure 1. Screenshot of the "Derivative" topic page. View it live at: ourbigbook.com/go/topic/derivativeVideo 2. OurBigBook Web topics demo. Source. - local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
- to OurBigBook.com to get awesome multi-user features like topics and likes
- as HTML files to a static website, which you can host yourself for free on many external providers like GitHub Pages, and remain in full control
Figure 2. You can publish local OurBigBook lightweight markup files to either OurBigBook.com or as a static website.
Figure 3. Visual Studio Code extension installation.
Figure 5. . You can also edit articles on the Web editor without installing anything locally. Video 3. Edit locally and publish demo. Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension. 
- Infinitely deep tables of contents:
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
Feel free to reach our to us for any help or suggestions: docs.ourbigbook.com/#contact