Exploring and Modeling Matter Phases and Changes

After some success last year with Mrs. Vissochi’s class and matter changes, it was apparent that more time had to be dedicated to understanding matter phases and how to model matter before such learning. So this year, Mrs. Finn opened her doors to experimenting with some new strategies for exploring matter phases and properties with her and Mrs. Hayes’ fourth-grade students. We passed over the traditional “read, recite, and move on” by starting with some formative assessment, confirming and addressing misconceptions through investigations over the course of a month leading up to winter break.

Day 1: The Six Cups of Mystery Matter

Following the suggestion of a December, 2008 Science & Children article, I brought six cups of “mystery matter” (air, water, salt, cornstarch, unifix cubes, and chocolate sauce) to the classroom and asked students to share what they think they knew about matter. The mystery matter acted merely as a prompt for student thinking at first, giving students the opportunity to describe the matter they saw before them before attempting to share “rules” they thought to be true about matter in general. After students exhausted their initial ideas, I asked them to share ways they could test matter to help them decide if the matter they were exploring was a solid, liquid, or gas. Testable properties and knowledge of matter varied across the classrooms (shared in the photographs below.)

Matter Chart 2 Matter Chart 1

At the conclusion of this lesson we informed the students that we would put their tests to THE test and conduct investigations of the mystery matters the next day.

Day 2: Testing the Mystery Matter

With some understanding of where students were at knowledge wise regarding matter, it was time to allow them to conduct their own investigations while Mrs. Finn and I took opportunity to help them better observe and articulate matter behavior.

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This was great fun for most groups, though the “air” group was found to be distracted by other group work as their interactions were limited and difficult to visually observe. Students recorded the behavior of their matter on recording worksheets before using the evidence collected to make a claim as to whether their matter was a solid, liquid, or gas. Most ultimately chose correctly, though they were conflicted when some of their testable “rules” turned out to be less than 100% fool-proof.

Day 3: BrainPOP and Checking What We Know

Students started the day with sharing their claims regarding their mystery matter with another group. After this share had taken place, students settled in on the rug to watch a free BrainPOP on the changing states of matter.

"Trusted sources," Tim & Moby

As a “trusted source,” Tim and Moby gave us an opportunity to check what we know versus what we learned from the short video.

Most basic ideas about matter were confirmed, though some revisions were made to improve “test” methods to better reflect our matter definitions. Student groups then revisited their claims regarding their assigned mystery matter, and then presented to the class sharing whether they continued to stand by their earlier claims or had changed their claims in light of new evidence and knowledge.

Photo Dec 10, 11 53 39

Checking our evidence against what we know about matter to make sure it supports our claim!

Knowledge confirmed and misconceptions addressed!

Knowledge confirmed and misconceptions addressed!

Day 4: Modeling Matter with a PhET Simulation

With a lot of background knowledge regarding matter now established, it was time to break out the sophisticated PhET matter simulation to give students more experience with modeling matter as moving particles and to provide time explaining what is physically happening to matter particles when matter changes phases.

Sharing what we observe about how matter behaves in the PhET model.

Sharing what we observe about how matter behaves in the PhET model.

Thermometer added to the left to support understanding of positive and negative temperature changes.

Thermometer added to the left to support understanding of positive and negative temperature changes.

After introducing how the model worked we got to observing and recording our observations on a class notepad. Students did a great job describing how the particles speed changed as heat was added and the differences between matter at solid, liquid, and gas stages. Their interest was piqued by the occasional particle that would seemingly “break free” (teacher note: evaporation!) of the liquid matter and how even solid matter particles appeared to have some motion associated with them. Some experience with negative numbers was necessary to understand the low temperatures at which the neon and argon gas operated in a solid and liquid phase. To help support understanding we drew a large thermometer to the left with a 0 Celsius in the middle, a +100 Celsius at the top and a -100 Celsius toward the bottom. Students were fascinated to see that the particle motion appeared to cease at -273 Celsius, though I did not share with them why. We also saved looking at the water molecules for later in the year when students explored the water cycle and weather, as the model introduced the complexities of water molecular polarity that I was not yet prepared to tackle with students, particularly in the 40 minutes given.

What we observed and learned from the PhET matter model.

What we observed and learned from the PhET matter model.

Day 5: Modeling Melting – Evaluating Student Understanding

Our experience with the PhET simulation gave us an opportunity to see how students visualized matter in more complex situations, such as when matter is melting, freezing, or dissolving solids in a solution. With winter break fast approaching this also acted as an assessment opportunity for the unit as a whole. Students entered the room to find two colored ice cubes in a plastic tub and a cup of hot water to the side. Students drew model sketches of the matter “as particles” and shared simple sentences explaining how the particles were moving or behaving.

Before hot water added.

Before hot water added.

After water added and ice cubes melted.

After water added and ice cubes melted.

It was no surprise that this challenged many students. Matter modeled as particles was only seen twice, once in the BrainPop and another during the simulation. Still many students were able to demonstrate some understanding of the model and matter behavior in the different phases. A few students even used the notes posted from the simulation and their own knowledge to construct their model (this behavior will have to be modeled more frequently in the future!) I’ve shared some of the results below, where some misconceptions are still visible, and some of the peculiarities of the PhET simulation (such as the occasional particle of matter escaping the bond of the solid and liquid particles to briefly evaporate into gas state before returning to the mix.)

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With more class discussion and exploration of the particle matter I believe teachers and students can expect improved results. Indeed, with the coming of curriculum adjustments to provide relief from the current “breadth over depth” mindset I’m very optimistic that these investigations, coupled with others using the particle model, will lead to deeper understanding of matter and its interactions and improve the experience and understanding students develop when students later explore combining matter later in a full matter unit. I want to thank Mrs. Finn again for her willingness to try new things and invite me into her classroom to explore matter with her students!

About Sean Musselman

Teacher Dad and Burlington MA Schools K-5 Science and Social Studies Curriculum Coordinator. NSTA Professional Development facilitator and author of "Think Like a Scientist: Investigating Weather and Climate" NSTA Kids ebook.
This entry was posted in 3-5, Classroom Activities, Digital Tools, NGSS and tagged , , , . Bookmark the permalink.

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