Custom CER Readings with ChatGPT: The Prompts, the Checks, and a Tested Example
A one-page reading built on a local phenomenon, with a claim-evidence-reasoning task at the end, takes an evening to write by hand. With ChatGPT it takes about twenty minutes, provided the teacher sets the rules before the AI writes a word. The prompts below were built for high school science teachers in Prince William County working on the division ChatGPT account, and they work for Biology, Chemistry, Earth Science and AP courses alike. The workflow is four moves: generate the reading, check it, copy the checked text into a Word file, and put the file where students get their work.
Start with one short prompt
Fill the three brackets and send it. The last sentence matters most: it makes ChatGPT ask you which words your students already know and which units they have not reached, so the reading is built for your class instead of an imagined one.
Help me, a high school [COURSE] teacher in Prince William County, Virginia, write a one-page student reading with a claim-evidence-reasoning task. Learning target: [TARGET]. Phenomenon: [A SPECIFIC PLACE, PERSON, OR MEASURED VALUE NEAR HERE]. Before you write, ask me what vocabulary my students have met and what they have not studied yet.
The full scaffold
This version does the whole job in one message. Replace every bracket, including the brackets inside the rules, before you send it. The vocabulary list is the single most important blank: paste in every term your students have met this year, unit by unit.
You are helping a high school [COURSE] teacher in Prince William County Schools, Virginia build a one-page student reading with a claim, evidence, and reasoning task attached. LEARNING TARGET: [CODE AND WORDING] STANDARD: [SOL CODE, OR AP COURSE FRAMEWORK OBJECTIVE] PHENOMENON: [ONE SPECIFIC PLACE, PERSON, OR MEASURED VALUE NEAR HERE] VOCABULARY STUDENTS HAVE MET: [LIST, UNIT BY UNIT] NOT YET STUDIED: [LATER UNITS AND TOPICS, BY NAME] THE TRAP IN THIS TOPIC: [THE IDEA STUDENTS MOST OFTEN CONFUSE] HARD RULES 1. Use no scientific term outside the vocabulary list unless you define it in plain words in the same sentence. 2. Do not depend on anything under NOT YET STUDIED. Where it is needed, describe it in plain words without naming it. 3. Define each key idea once and use it the same way every time. Watch THE TRAP. 4. Every real-world claim must be checkable. Under a heading SOURCES TO VERIFY, list each claim and the specific source to check it against. Do not invent citations, page numbers, or numbers. 5. Include at least three real quantities with units, each listed under SOURCES TO VERIFY. If you are unsure of a number, put it under UNCERTAIN instead of in the reading. 6. Put anything you are unsure about under a heading called UNCERTAIN. WHAT TO PRODUCE Title: concrete and specific, not a question. Opening of 100 to 150 words: the first sentence names a place, a person, or a number. Three body sections of 120 to 150 words each, with plain headings that teach rather than tease. Key vocabulary: four terms from the list, one sentence each. One CER task: a claim prompt the student answers, told to cite at least two pieces of evidence from the reading and explain the reasoning. Put the STANDARD code after the task. Total 600 to 750 words, written for [GRADE OR COURSE LEVEL]. Write the reading.
If your account lets you choose, use a reasoning model rather than the fast default. In testing, the fast model produced flatter writing and the one real science error described below.
Follow-up prompts that fix the usual problems
Send these in the same chat, after the first draft comes back.
List every scientific term you used that is not on my vocabulary list, and rewrite each sentence that uses one.
Quote every sentence where you define or explain [KEY IDEA]. Do they all mean the same thing? If not, fix the reading so they do.
Rewrite the opening so the first sentence names a specific place, a person, or a number. Keep everything else the same.
Keep every fact, number, and vocabulary term the same, and rewrite this reading in shorter sentences for students who are still learning English.
What happened when the prompt was tested
Tested September 13, 2026Road salt and cell transport
The first version of the scaffold was run on the PWCS division account, using the default fast model, against Biology LT 2.5 Cell Transport with road salt on Northern Virginia roads as the phenomenon.
What held. Every scientific term came from the vocabulary list. Asked not to name ATP, it wrote "energy" instead. The sources it listed to verify were real and specific (VDOT, USGS, the Federal Highway Administration, Virginia Cooperative Extension, the EPA), with no invented citations, and it volunteered an honest UNCERTAIN note.
What broke. Diffusion was defined as movement "from an area of higher concentration to an area of lower concentration." A few lines later, water moved "from where there is more water to where there is less available water." Each sentence can be defended alone; together they point a careful student in opposite directions. The draft also opened on a general statement rather than a place, and it contained no numbers at all.
Those findings became the extra rules in the full scaffold: one consistent definition and a named trap, three real quantities with units, an opening that names something specific, word budgets for each section, and the standard's code on the task.
Filling the blanks in other courses
Only the biology row was tested. The others are starting points showing how the same blanks fill in other courses.
| Course | Phenomenon | The trap |
|---|---|---|
| Biology · cell transport | Road salt on Northern Virginia roads, roadside plants, and the streams it drains into | Concentration of dissolved material versus concentration of water |
| Chemistry · gas laws | The tire-pressure light on a cold October morning | Temperature in degrees Celsius versus kelvins |
| AP Biology · evolution | Who can still digest milk as an adult, and why | Individuals adapting versus populations changing |
| AP Chemistry · acids and bases | Changing water chemistry at Chesapeake Bay oyster reefs | A strong acid versus a concentrated one |
| Earth Science · water | The Occoquan Reservoir after a heavy rain | Dissolved material versus suspended sediment |
The four checks, for you and your students
AI writes with the same smooth confidence whether it is right or wrong, so every draft gets checked before it reaches a student. Students run the same four checks on any AI-written science text, which puts the judgment in their hands.
- TRACE. Underline every claim about the real world. Find it under Sources to Verify, open one source, and confirm it says the same thing.
- FLAG. Circle every science word students have not learned. If the sentence does not explain it, flag it.
- COUNT. Box every number. Each needs a unit, and a good reading gives at least three. A reading with no numbers gives students no evidence to cite.
- MATCH. Find the key idea and highlight every place it is explained. Every explanation should mean the same thing.
Getting the reading onto the student iPad
- Copy the checked text into a Word file. Students type their CER straight into it on the iPad, and it saves as they go.
- Post the file where students get their work, and have them upload the finished file.
- Keep PDFs out of anything students type into.
- Canvas Student Annotation seals each attempt, so a student cannot pick the work back up at home.
- Word on the iPad cannot insert a chart. If the task needs a graph, give students the graph.
- Several students can work in one shared Word file, which opens up tasks built on class data.
Share yours, and borrow someone else's
Prince William County science teachers can add finished readings to a shared CER library in OneDrive and use any reading already there. Sign in with your PWCS account to open it: scienceonepagers.org/cer-share.
- Save the reading as a Word file.
- Put your initials and school at the front of the file name, then keep your own title: RS_BFHS_Road Salt and Cell Transport.docx.
- Drop it in the folder named _Drop your CER here. Readings are filed by course with one consistent name, and your initials stay in it.
- To use someone else's reading, save a copy first and adapt the copy. No student names or student work.
Running the reading in class
A reading works best when students read it alone, talk it through with a partner, and then write the CER on their own. How to run that protocol, how to score the writing, and how to fit it into a short week: Read, Talk, Write: Running a CER So Students Argue Before They Write.
Written for "From Learning Target to iPad: Creating Custom CER Readings with AI," a session by Reid Schwebach and Katie Novinger at the PWCS October ACT Conference, October 12, 2026, Hylton High School. Test run: ChatGPT (GPT-5.5 Instant) on the PWCS education account, September 13, 2026; quotations are from that draft. Finished CER readings to use as models are in the Biology section of this site.