States of matter is one of those “everyone thinks they already know it” topics… right up until students hit phase changes, particle models, and the weird edge-cases that don’t behave the way the textbook diagrams suggest. That’s exactly why I love teaching it with surprising, explainable facts. A great states of matter lesson is not just solid, liquid, gas.

It’s a guided tour of why matter behaves the way it does when energy, pressure, particle motion, and structure collide.

If you want a ready-to-use classroom version built around Strange But True Facts + Two Truths & a Lie, this resource matches today’s post perfectly (and works as a lesson opener, review, station activity, or sub plan) - States of Matter Strange but True Facts + 2 Truths & a Lie Activity Set

And if you like pairing wow moments with deeper thinking, there’s also a companion scaffold that turns states of matter into structured reasoning and inquiry (with multiple support levels) - States of Matter Critical Thinking Framework Resource.

Now let’s jump into 7 amazing facts you can use tomorrow, plus practical ways to teach them.

How to teach states of matter so students actually remember it

Before the facts, here are three classroom structures that consistently work for Grades 6–10:

1) Two Truths & a Lie (10–15 minutes)

Give groups three statements. Two are true, one is false. Students must:

• choose the lie

• underline the key clue

• write a 2–3 sentence explanation using particle language (energy, spacing, motion, attraction)

This is exactly what the States of Matter Strange but True Facts + 2 Truths & a Lie Activity Set is designed to do, with both presentation and student-ready formats.

2) Explain the Weirdness mini-CER (8–12 minutes)

Students pick one fact and write:

• Claim: what the fact shows about matter

• Evidence: the detail or number that matters

• Reasoning: a particle model explanation

3) Stations that feel like a lab, without the mess (25–35 minutes)

Each station is one fact + a diagram + 2 questions:

• one “what is happening?” question

• one “what would change if…?” variable question (temperature, pressure, surface area, particle size)

If you want a wider menu of chemistry reading passages that support this kind of station work, these chemistry collections make it easy to mix and match.

Enhanced Differentiation Chemistry Reading Comprehension 42 Passages | 35 Topics

or

Chemistry | 30 Chemical Related Reading Passages + 30 Research Project Templates

The 7 Amazing Facts (with classroom-ready teaching moves)

Fact 1: Water can exist as a solid, liquid, and gas at the same time

At a specific temperature and pressure called the triple point, ice, liquid water, and water vapor can coexist in equilibrium. For water, the triple point is at 273.16 K (0.01°C) and a vapor pressure around 611.657 Pa. (NIST Publications)

How to teach it (fast and effective):

• Put three circles on the board labeled solid, liquid, gas.

• Ask: “What must be true about particle energy and pressure for all three to balance?”

• Extension prompt: “Why don’t we see triple points in daily life?”

Best misconception to target:Students often think phase change is only about temperature. The triple point makes pressure impossible to ignore.

Fact 2: Dry ice doesn’t melt into a liquid, it skips straight to gas

At normal atmospheric pressure, solid CO₂ sublimates directly to CO₂ gas (no puddle), which is why you see “fog” and not liquid carbon dioxide. Sublimation temperature is about -78.5°C at 1 atm. (Department of Chemistry)

How to teach it:

• Show a phase diagram sketch and ask: “Where is the liquid region?”

• Mini investigation question: “What would we have to change to make liquid CO₂ possible?”

Low-prep demo idea: Even a short video clip of dry ice in a balloon leads to great discussion about gas production and pressure (and it’s safer than improvising with dry ice if you do not have proper handling conditions).

Fact 3: Oobleck can act like a solid or a liquid

Cornstarch + water (oobleck) is a non-Newtonian fluid. Under sudden force it stiffens, but under slow movement it flows. That solid when hit, liquid when gentle behavior is a classic way to introduce shear-thickening. (Science Learning Hub)

How to teach it:

• Quick-start question: “Is it a solid or a liquid?” (Force students to justify.)

• Then flip it: “What counts as a state of matter in school science, and why do we simplify?”

Best classroom payoff: It gives you a clean reason to talk about models: we sort matter into categories because it helps us explain patterns, even though nature is messy.

Fact 4: Lightning is not just hot air, it’s plasma

Lightning heats and ionizes air so strongly that it becomes plasma, with ions and free electrons. NOAA’s education resources describe lightning’s ionization and plasma nature in accessible classroom language. (NOAA Physical Sciences Laboratory)

How to teach it:

• Ask: “If plasma is a state of matter, what makes it different from a gas?”

• Key language: ionization, charged particles, conductivity.

Simple connection students like: Neon signs, auroras, and stars. Suddenly “states of matter” becomes a bridge to space science and electricity.

Fact 5: Glass is a frozen liquid in an unordered state (kind of)

Here’s the nuance students love: glass feels like a solid, but it does not have a neat repeating crystal lattice. It’s commonly described as an amorphous solid with disordered structure. Scientific American has a clear explainer addressing the glass is a liquid myth while explaining why glass is best treated as an amorphous solid. (Scientific American)

How to teach it without headaches:

• Tell students: “Glass is solid for all practical classroom purposes.”

• Then add: “But its internal structure is not crystal-ordered like salt.”

• Ask: “What properties would change if the structure were crystalline?”

Why it matters: This is a perfect moment to show students that scientific categories are tools, not cages.

Fact 6: Some substances expand when they freeze instead of shrinking

Most materials get denser when they freeze. Water is the famous exception: its crystal structure holds molecules farther apart, so ice is less dense and floats. Some sources note the volume increase is about 9% when water freezes. (courses.ems.psu.edu)

How to teach it:

• Ask: “Why do lakes freeze on top first?”

• Then: “Why is that good for life in winter?”

Easy real-world hook:Cracked rocks, burst pipes, frost wedging. Suddenly phase change has consequences.

Fact 7: Fine sand can behave like a solid, a liquid, or a gas

Granular materials like sand are famous for acting solid when supporting weight, liquid when flowing through an hourglass, and gas-like when grains are suspended and colliding in a cloud. MIT has a great everyday-life explanation that frames this in a way students immediately get. (meche.mit.edu)

How to teach it:

• Ask: “What is the ‘particle’ here?” (The grain, not the molecule.)

• Then connect: “So why does it behave differently than a liquid?”

Best extension question:“How does particle size change behavior?” This sets you up for powders, aerosols, and even planetary science (dust storms, dunes).

A simple 3-day mini-unit you can run without rewriting your curriculum

Day 1: Hook + misconceptions (low prep, high payoff)

• Two Truths & a Lie using states of matter facts

• Students justify with particle motion and energy

• Exit ticket: “One misconception I had, and what fixed it”

Resource that’s built for exactly this workflow - States of Matter Strange but True Facts + 2 Truths & a Lie Activity Set

Day 2: Reading passage + diagrams + vocabulary

Use a short reading to stabilize the model (solids/liquids/gases, heating curves, pressure basics). If you like differentiated text, this dual set is an excellent companion because it directly targets particle models and phase change thinking - Are there three kinds of stuff? - dual reading passage resource.

Day 3: Make thinking visible

Students pick one weird fact and build a deeper explanation using structured reasoning. If you want a scaffold that supports mixed readiness levels (from “I need sentence starters” to “I can evaluate limitations”), this framework is designed for that - States of Matter Critical Thinking Framework Resource.

Where to find more matter-and-properties resources (without digging)

If you want to browse a tight collection around matter, properties, acids/bases, metals, and linked reading passages, this category page is a useful library shelf to pull from - The Teaching Astrophysicist Matter and its properties resources.

And if you like the “facts + reasoning” angle across chemistry, here’s the chemistry Strange But True hub - Strange but true facts + 2 truths and lie resource.

Thanks for reading

Cheers and stay curious

Oliver - The Teaching Astrophysicist