
Sodium Polyacrylate
In science, my 4th graders are learning about the Law of Conservation of Matter after about a week of reviewing ideas around solids, liquids, and gases. Instead of doing the classic cornstarch and water lab, I decided to try something new this time around. If you go online, you can find packets of this stuff called “Instant Snow.” Instant snow is a powder (sodium polyacrylate crystals), and when you add water, a polymer reaction occurs. The powder increases in volume by up to 100 times, and it looks like…instant snow. It’s a cool experiment because you’ll have a teaspoon of powder, add 100 ml of water, and suddenly your Tupperware container is overflowing with fluffy “snow.”


Fun fact: this stuff is commonly used in diapers because it soaks up liquid, and it’s why a wet diaper is so squishy and fluffy. Sorry…TMI?
My wife, @HannahGriebling, is a scientist (currently working on a PHd. in Animal Behavior and Cognition/Urban Ecology), and one thing I have noticed over these last few years is that, in addition to experimentation and field work, scientists read a lot and write/publish a lot. So I’m always looking for ways to do this kind of working my science class. But how does one do this in a way that is, you know, interesting and kid-friendly?
Here’s what we’re trying…
Phase 1: Open Play + QFT
One thing I’ve been trying to do more this year is allow for a bit of play before experimenting. Getting to just putter around with the instant snow before digging into the unit of study allowed students to get familiar with the substances they’d be experimenting with.
I gave each group of students a tablespoon of the sodium polyacrylate crystals, a cup of water, and some safety goggles. I told them that when they mixed the two together there’d be a reaction, and that we would eventually be exploring this reaction by creating and performing controlled experiments.
The first group added all their water at once, and suddenly their container was overflowing with snow. When another group saw this, they did the same thing. A third group decided to try a couple different things; they added a little bit of water at a time and they noticed that it first the mixture turns to something that looks like slush for just a few seconds before turning into “snow.” I asked students to stop and write down all the things they noticed along with any questions they had.
After writing for a few minutes, students started sharing their questions, and I wrote them all up on the board. This is where I used a strategy called Question Formulation Technique, or QFT for short (stolen from @trev_mackenzie).
I asked students which questions we could find a quick answer to (What is the powder? How much bigger can it get when mixed with water?) These would be called “Closed” questions. I asked which questions would require multiple answers…or some exploration. (What can it be used for? How does it react with various liquids?) These would be “Open” questions.
I gave students time to think and debate which questions would be open and closed. I also asked students which closed questions could be open questions if we change the wording.
From there, I chose one to be one an essential question to go along with one that I’d already chosen (How does the law of conservation of matter work?)
Phase 2: Designing Experiments Around Open Questions
After that, I put students into groups to devise controlled experiments that would help us address some of our open questions (but not the essential questions just yet). Some explored the effect of temperature on the reaction, and others explored how the reaction works when adding different liquids/substances to the polyacrylate crystals.

For round two, I showed a video about the Law of Conservation of Matter. Then, I asked students to write in their science notebook about whether the Law of Conservation of Matter was in play with instant snow. After all, when mixed with water, the stuff increased in volume exponentially.
After a bit of thinking on paper, I asked students to bring their ideas to their groups. From there, they had to devise a controlled experiment. This time there would be added focus on observation, measurement, and documentation.
The groups eventually took turns proposing their experiments to the rest of the “Lab,” and after some refining, each did a variation on measuring the volume and mass of ingredients before and after mixing.
For each reaction, although the volume had changed, the mass hadn’t. Groups came up with conclusions to explain why this had happened.


Mentor Texts
For past experiments, we’d written and recorded podcasts, but this time, I wanted students to try out something akin to the kinds of writing real scientists do. In my search for mentor texts, I found some real gems! Each of the below contains collections of scientific articles in kid friendly language.
- https://kids.frontiersin.org: written and formatted as a scientific journal, but for kids. Visually appealing scientific articles–complete with abstracts, references, young peer reviewers, and citations.
- https://www.sciencejournalforkids.org/: free version is similar to kids.frontiersin.org, but you can get a paid teacher account to unlock extra educator features.
- https://www.dogonews.com: similar to TweenTribune, but with a focus on Science and Social Studies.
- https://www.sciencenewsforstudents.org: scientific feature articles, written with playful but authoritative voice.
- https://www.sciencea-z.com/: this one’s like newsela, but for Science. It’s made by the ReadingA-Z folks.
This time, we ended up reading a news report from dogonews.com about a research facility in Germany that performed experiments around fish being able to perform simple addition and subtraction problems.
On our first pass, I just asked students to mark anything that seemed interesting or confusing. Then we discussed.
On the second pass, I asked them to read as writers, and mark what they noticed the writer doing in each paragraph or section. They noticed that it opened with a hook. They also noticed that the author went on to give background information on fish cognition before getting into the heart of the experiment. They even noticed some points of confusion where they would have written it differently.
In spite of all the experimentation we’d done, as I looked over students’ Science Notebook entries, I wasn’t sure if students had enough content to write this kind of piece just yet. So I asked, “What else would you want to know about polyacrylate crystals in order to have enough ideas to write a piece like this?”
They came up with another list of questions, and in effect, planned out my science lessons for next week. After this last round of experimentation, we’ll revisit the mentor text and write articles of our own.
I’ll let you know how it goes next month!
The secret sauce in all this is our cycle of playing, questioning, and experimenting. They play leads to big questions–which then leads to more meaningful experiments. When (Science) writers have meaningful experiences to write about, it makes the writing more meaningful. Of course there’s the audience factor, as well, which we will get into next time…
How do you employ inquiry-based writing across the curriculum? I’d love to hear from you! Comment below and follow me on Twitter @MrWteach. While you’re there, be sure to follow @MovingWriters, if you don’t already!
You know I’m into this… hoping our science classes can collab eventually.