The facts were real. The frame was not fair.

What this lesson is for

Students hear a steady stream of accurate facts about a chemical called dihydrogen monoxide. Erosion. Burns. Deaths. Nuclear reactors. They vote on what to do about it. Then they learn it is water.

The reveal is not the lesson. It is the setup. The lesson is the recovery: once students feel what selection, omission, and borrowed authority did to their judgment, they get a method they can use on the next claim. That method is the WATER Check: Wait, Ask, Trace, Examine, Respond.

The line to keep repeating: the facts were real, and the frame was not fair.

One honest note up front. I did not invent DHMO. The dihydrogen monoxide parody is decades older than my classroom. What I built is the sequence around it: the order of the claims, the vote, the debrief, and the move from gotcha to practice.

Who it is for

High school classes: journalism, English, social studies, civics, and library instruction. The claims and the debrief assume students can handle a little discomfort and a public mistake that is not really theirs. If you teach younger students, the 15-minute DHMO introduction on the teaching page is a gentler entry point.

Learning purpose: students explain how accurate information can still mislead through selection, omission, unfamiliar language, sequence, and authority cues, then apply WATER to check a claim by leaving the page and finding outside evidence.

Materials

• A projector and a short run of slides, one claim per slide (the claims are below).
• A way to vote. A free poll tool works. So do hands. The method matters more than the tech.
• Optional prop: a clear beaker or bottle with a readable DIHYDROGEN MONOXIDE label, and a WATER or H2O label hidden on the back or under a cover until the reveal. Use only water. Nobody drinks from it.
• Access to DHMO.org for the lateral reading step, projected or on student devices. A printed screenshot works if devices are a problem.
• Paper for the rewrite at the end.

The claims

Every claim is true. That is the point. Keep the pace brisk and say fewer words on the scary slides. The sequence does the work.

1. There is a chemical you should know about: dihydrogen monoxide. In pure form, practically colorless, odorless, and tasteless. (USGS)
2. It contributes to erosion. Stone, concrete, metal.
3. Hot vapor can cause serious burns. (NHS)
4. About 300,000 people die from it worldwide every year. (World Health Organization)
5. It is used to cool nuclear reactors. What does that make you assume? (NRC)
6. Exposure is essentially universal. Homes, schools, hospitals, farms, factories.
7. You cannot completely avoid it.

Put the source on the slide. Students should see the authority cue working on them, because they will name it later.

The 45-minute sequence

If you are running behind, move faster through the claims. Do not cut the vote, the reveal, the WATER step, or the close.

0 to 3 minutes: Frame

Tell students you are going to give them a series of claims about a chemical. Their job is not to solve a riddle. Their job is to watch their own decision-making as the information piles up.

3 to 14 minutes: The case

Run the claims. Let the prop sit in view if you use one. Do not overact.

14 to 22 minutes: Vote, reveal, debrief

Ask for a public choice: What should we do about DHMO? Ban it, regulate it, require warning labels, or do nothing. Give students a fifth option out loud: need more evidence, hold your vote. Ninety seconds is plenty.

Then ask the most important question of the first half: What evidence would change your mind? Pause. Let it sit.

Reveal it. “Dihydrogen monoxide is water. The facts were real. The frame was not fair.” Then ask partners to compare notes on one question: What did I leave out?

Name the moves together. I selected danger. I left out benefits. I used unfamiliar terminology. I arranged facts into a story. I borrowed the voice of scientific authority. I did not have to lie to mislead anyone.

Then put the conditions back:

• Hot vapor burns: that depends on temperature and exposure.
• About 300,000 deaths a year: drowning, not poisoning.
• Nuclear reactors: cooling is an application, not a hazard label.

The risks are real. So is the missing context.

22 to 36 minutes: WATER and lateral reading

Now turn the gotcha into a method. Put the five questions up:

• Wait. What emotion is pushing me?
• Ask. What is the actual claim, and what would count as evidence?
• Trace. Where did this start?
• Examine. What language, crop, number, comparison, or authority cue is shaping the meaning?
• Respond. What is missing, and what do I do now?

Then send them to DHMO.org. Ninety seconds, one partner, one claim. The job is to leave the page, find an outside source, and bring back evidence, not a verdict. This is lateral reading, the move Wineburg and McGrew documented among professional fact-checkers: open new tabs and find out who is behind the page instead of staying trapped inside it.

Somebody will find the fine print. The site says, in its own About section, “Content veracity is not implied.” That is a great classroom moment, because it does not let students stop at “the website tricked me.” The warning was visible. What did they ignore because the page looked official?

36 to 43 minutes: Write the version you would share

Four minutes. Each student writes one fair headline or short post about water. Name the specific risk. Include the source and the missing context. Swap with a partner, and each person revises one thing.

43 to 45 minutes: Close

End on the question, not the trick: What am I missing? Then go find it. Not knowing everything is normal. Knowing what to do when you do not know is the skill.

Keep it ethical

You are deliberately misleading a room of students for a few minutes. Earn that.

• Use only true claims with real sources. No fake agency seal, no invented warning, no pretend chemical hazard.
• Keep the vote low stakes. The point is the class decision, not who fell for it.
• After the reveal, shift from clever to generous immediately. Say “What happened to our attention?” and not “I tricked you.”
• Do not apologize for the demonstration. Debrief it. The discomfort is part of what students will remember.
• Land on calibrated trust. Cynicism is not media literacy. It is often just another shortcut.

What it shows, and what it does not

It shows students, in their own reactions, that accurate facts can be arranged into an unfair story, and that the missing context matters as much as what gets said.

It does not prove that students will check the next claim they see. It is one lesson, not a cure for the internet. What it can do is build a pause and give that pause a routine. Plan to practice WATER again on claims students actually encounter, and assess their evidence trail, not whether they got the “right” answer.

Where to take it next

These extensions come from the same session deck. Use one, not all of them.

• Numbers: a 100% increase sounds huge. So does going from one case to two. Ask: compared with what, over what time, out of how many?
• Images: an authentic image can carry a fabricated claim. Ask what original context was removed, then go find the original.
• AI: a model can produce a fluent, truthful, misleading paragraph on request. Have students annotate one for selection, omission, authority, and emotional language, then verify every number.
• History: the BBC’s 1957 spaghetti harvest broadcast is a good case for asking what carries credibility in a report and what you would check.
• A full practice lesson: the free Lunch Line Claim lesson moves from counts to rates, repeated claims, and a simulated AI summary, with a student handout and teacher key.

About this lesson

Lesson sequence and teacher notes by Eric Jourgensen, Ed.D., a high school journalism teacher and student media adviser in Palm Beach County, Florida. I am presenting this session, “Dihydrogen Monoxide: The ‘Deadly Chemical’ That Exposes How Misinformation Works,” on Oct. 9, 2026, at the National News Literacy Conference in Salt Lake City. The National Press Club Journalism Institute wrote about how I use the exercise with students.

Published Sept. 22, 2026. Sources cited in the claims were checked for this page in September 2026. Check them again before you teach, because good sources get updated.