Checking the physics
What stands behind each statement on this site, what was tested by machine, and what nobody has tested yet. Page revised 2026-10-26.
The bar a fact has to clear
A fact appears here only if one of the documents in the site's source list states it. That list holds twenty documents from five kinds of publisher:
- the US Energy Information Administration, eleven pages of its Energy Explained series and one of its answers to common questions;
- the National Institute of Standards and Technology, three pages on SI units and conversion factors;
- NASA Science, two pages on the Sun and on electromagnetic waves;
- Virginia Cooperative Extension, one publication on estimating what appliances use;
- Penn State and a Gettysburg College physics course on LibreTexts, one teaching page each.
Company material, blogs, forums and shop pages were not used. Two Department of Energy pages and three Georgia State physics pages were on the first list, but they could not be fetched, so nothing on the site rests on them.
The connecting sentences between facts, the order of ideas and the worked examples are the site's own. Every worked example uses invented round numbers, is marked as an example and stands for no real household, product or company.
What the automated check did
| Step | Result |
|---|---|
| Date | 2026-10-26, shown on each guide as its "last reviewed against sources" date |
| Requests | One download per document, no retries |
| Documents reached | 20 of 20 answered normally |
| Facts searched for | 136 short patterns, such as a conversion factor or a defining phrase |
| Facts found in the page text | 136 of 136 |
Some patterns were added after the download. Those were tested against the text saved from that same download, without asking the publisher's server a second time.
What the check cannot tell you
Finding a number on a page shows the number is there. It does not show that a guide uses it correctly, that its explanation of the number is right, or that a sentence with no pattern attached is right. Those things are untested by machine, and no human editor or physicist has reviewed the guides. The arithmetic in worked examples is shown line by line so readers can redo it; the site's own test suite recomputes some kilowatt-hour and kilocalorie conversions, but not every sum.
Units and statistics
Conversion factors are copied in value, not wording, from NIST's alphabetical table or from the EIA, and the units table names which one. A statistic such as a share of US electricity generation carries the year its publisher gives and is never projected forward.
Machine drafting
An AI system produced the first and current text of every guide, working from the documents above. The drawings are hand-written vector drawings in SVG, made for this site; none is a photograph or a generated image.
Money and influence
No company, agency or utility pays for, sponsors or has seen these pages. No product is named or recommended, and kit is described by what it does. Source documents are named in the text rather than linked for now; if links are ever added, any that were paid for will say so.
A snapshot, not a subscription
The download in the table above happened once, on 2026-10-26, and is not set to run again. Publishers revise their figures, and the EIA recalculates its fuel heat-content factors each year, so a number here can fall behind the document it came from without anyone noticing. Where the two disagree, believe the publisher's current page; look the title up there before leaning on a figure. Readers have no way to report a slip either, because the site has no contact route, so an error may simply stay in place. A page that gets amended shows the amendment date on that page.