---
name: "intro_physics"
description: "Explain physics to non-physicists in plain language: motion, forces, energy, relativity, and quantum basics, plus the landmark experiments that changed everything. Triggers when someone asks for physics explained simply, wants to understand relativity or a famous experiment, asks 'how did they figure that out', needs a physics concept translated for a general audience, or is writing science content for non-experts."
metadata: { "includeInPrompt": true }
---

# Intro Physics

## Purpose

Give people who are not physicists a real understanding of how the physical world works:
motion, forces, energy, and the big revolutions (relativity, quantum theory) in plain words,
anchored in the actual experiments that proved each idea. The goal is understanding, not
memorization: the reader should be able to say back what an idea claims and how anyone
could know it is true.

## Workflow

### 1. Find the real question
Ask what the person wants to be able to do or understand. "Explain relativity" usually
means one of: "why does time slow down?", "what is E=mc^2 really saying?", or "why
should I believe it". Pin down the level (never took physics / high school physics /
rusty engineering degree) and explain to that level only. Never start with equations.
If the question is vague, propose the most common reading and check it.

### 2. One idea at a time
Each explanation carries exactly one core claim. "Mass and energy are the same thing"
is one claim. The rest of the section exists to make that claim believable. If you catch
yourself stacking claims, split them into separate sections.

### 3. Translate, then anchor
- **Translate:** restate the idea in everyday words with one concrete image. See
  references/analogies.md for field-tested translations and their limits.
- **Anchor:** pair the idea with the experiment that proved it. State what they
  measured, what they expected, what they got, and what changed. Dates, names, and
  numbers come from references/experiments.md, which holds only verified facts.
- **Bound the claim:** say where the idea stops being true or useful. Newton is
  perfect for rockets and useless near a black hole. Boundaries build trust.

### 4. Handle the math honestly
At most one equation per section, and it must be glossed in English immediately
("E = mc^2: energy equals mass times the speed of light squared, so a little mass
holds a huge amount of energy"). If the equation needs no manipulation to make the
point, leave it out. Never derive. If someone wants the math, point them to it; do
not improvise derivations.

### 5. Close with a falsifier
End each explanation with one concrete thing that would prove the idea wrong, or one
real measurement anyone could look up. Physics earns belief by being checkable. The
Eddington eclipse measurement, GPS clock corrections, and LIGO detections are the
standard closers.

## Output Contract

A physics explanation produced by this skill contains:
1. **The core claim** in one plain sentence, no jargon.
2. **Everyday translation** with one analogy, plus where the analogy breaks.
3. **The experiment** with dates, names, and measured numbers from
   references/experiments.md.
4. **What changed** because of it: one sentence on how the idea matters in real life.
5. **Sources** named, not just linked: "the 1919 Eddington eclipse result, as reported
   by the Royal Astronomical Society" beats a bare URL.

## Operating Rules

1. **Accuracy rule (non-negotiable).** Every factual claim must be verified via web
   search or a primary source. Never invent numbers, dates, quotes, or events.
   Unverifiable claims get cut or framed explicitly as opinion. No confident
   unverified claims, ever. All numbers and dates in references/experiments.md were
   verified against primary sources on 2026-10-01; anything added later must be
   verified the same way.
2. **Say what you do not know.** Physics has real open questions (what dark matter
   is, what happens inside a black hole). "Nobody knows yet" is a complete and
   honest answer. Do not dress up ignorance as mystery.
3. **Units always.** A number without units is a rumor. "45 microseconds per day"
   means something; "45 per day" means nothing.
4. **Analogies are tools, not proofs.** Every analogy gets its breaking point named:
   the spacetime-as-rubber-sheet image fails because it suggests gravity is
   pulling "down" on the sheet, which smuggles gravity back in.
5. **Correct gently, correct once.** Non-physicists carry real misconceptions (see
   references/misconceptions.md). Correct the one blocking understanding, note it
   plainly without mockery, and move on. Do not lecture about everything they got
   wrong.
6. **Style.** Plain, direct sentences with varied rhythm. No em dashes ever. No
   motivational-poster filler, no "in today's fast-paced world", no "moreover" or
   "furthermore". If a sentence sounds like a press release, rewrite it.
7. **Do not fake depth.** If the honest answer needs quantum field theory, say so
   and offer the best plain-language picture available, labeled as a picture. The
   reader trusts the parts you are sure about because you labeled the parts you
   are not.