Category Archives: Ambitious Science Teaching

Transforming a Physics Lessons about Wave Properties

Are you transforming your physics course to NGSS? I took an old lesson of mine about properties of waves and transformed in to a phenomenon-driven storyline.

The original activity was an inquiry-based lesson on wave properties. You can find it on the PhET website. I wanted to update this lesson to align with the NGSS vision.

The first thing I needed to do was identify an anchoring phenomenon for my topic. My focal NGSS performance expectation is HS-PS4-1. I wanted to use the Waves on A String simulation again, so I needed a phenomenon that would fit. I found this video on YouTube.

The video provides a perfect opportunity for students to notice patterns between the waves on guitar strings and the sounds that they hear. I decided to use this as my anchoring phenomenon. I asked students:

  • What patterns do you notice in the video? 
    • What do the patterns on the strings look like as they are being played? 
    • Do you notice any relationships between the patterns of what you hear and what you see? 
  • What do you think causes those patterns?
  • Create a model to record your ideas using this Google Jamboard.

I frame the students initial ideas about the phenomenon in terms of the crosscutting concepts. In high school, students are expected to use empirical evidence to identify patterns.

This opening activity creates curiosity about the phenomenon and prompts students to ask questions about the relationships among wavelength, frequency, amplitude, and the medium (the guitar string).

The original sequence is a good fit for students to figure out how and why different guitar strings produce different sounds as they also address the content of HS-PS4-1. Here is a link to the finished lesson.

Let me know what you think about this lesson!

Waves on a String by Lori Andersen is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
Based on a work at

Developing a Particle Model of Matter

On September 15, we started Lesson 2-3 of The Garbage Unit. This lesson develops the idea that solids and liquids are made of particles and uses this idea to explain sugar dissolving in water. The day before this lesson, students made predictions about what happens to sugar when we dissolve it in water. Most students believed the sugar was still there because they could taste it in the water. Some students said that it was not still there because it disappeared. I asked them how they could gather evidence to determine if the sugar was still there. They suggested tasting the water. I reminded them of our prior investigations that used weight as a property and asked how we could use weight to see if the sugar was still there. Some students suggested that the weight could be evidence.

On the first day of this lesson, students investigated mixing sugar into water. They measured 50 ml of water and weighed the water. They weighed a spoonful of sugar. Then they mixed the sugar into the water until it dissolved. They weighed the mixture. While students were following directions and making their measurements, I circulated the room. I noticed that some students were getting erroneous data because they were not taring the scale correctly. I helped three of the six groups collect a second set of data to ensure they would all have accurate data to use to answer the four questions. If (I had not done this, they would not have noticed that the pattern that they need for later— that the weight of the water and the weight of the sugar add up to equal the weight of the mixture.)

Students answered four questions about the investigation with their groups. I collected the papers to see their thinking. One issue I noticed was that many students did not understand the concept of volume. When asked what happened to the volume after the sugar was mixed in, most students used the weight data to answer the question, rather than thinking about the amount of liquid in the cup.

I filmed a demonstration of the investigation to show as a review the next day to ensure all students could make the observations they needed.

The next day, I returned their investigation papers and we talked about volume. This is an important idea that they need to explain in their models.

Markings to indicated liquid level

We talked about the marks we made on the cup to show the amount of space the liquid takes up, or its volume. First we marked the level of water, then we made a new mark for the level of the mixture. We decided that the volume did not change much, it increased a small amount. How could this happen? We needed to figure that out.

The second day focused on developing a particle model of matter. Students read a short article called What is matter made of?

From NYU SAIL The Garbage Unit Lesson 2-3

Then we discussed what we learned from the article. Solids and liquids are kinds of matter that are made of particles. All matter is made of particles.

Flinn Scientific

Next, we watched a video that showed a physical model for particles and discussed the model. In this model, ping pong balls were put in a beaker.

Flinn Scientific

Then marbles were added to the same beaker. The marbles fit in the spaces around the ping pong balls.

Adding the marbles to the cup did not change the volume much. We explained how the ping pong balls were like the water particles and the marbles were like the sugar particles. The water particles have empty space around them like the ping pong balls do. The smaller sugar particles can fit in the empty spaces like the marbles fit around the ping pong balls.

Students worked with a partner to talk about their ideas. Then they each completed an exit ticket that asked how the particle model could explain why the volume did not change much when sugar was added to water. I collected the exit tickets and found that many students only represented the sugar as particles, but not the water.

On the third day, we will review the information we have about mixing sugar and water. We have three sources of information—investigation findings, the reading, and the physical model in the video. I made a video to recap.

We will create our own system models that use particles to provide a cause and effect explanation of what we observed in the investigation. Students work collaboratively to create models using Google Slides. I made a template with a fixed background of the cup and spoon. Students can drag the particles to show how they are arranged. They create before and after models and write their explanations on a third slide.

In this lesson, students are using four crosscutting concepts together as they generate their explanation for the phenomenon of sugar mixing with water.

  • 3-5-CCC1.3: Patterns can be used as evidence to support an explanation.
  • 3-5-CCC2.1: Cause and effect relationships are routinely used to explain change.
  • 3-5-CCC4.2: A system can be described in terms of its components and their interactions.
  • 3-5-CCC5.1: Matter is made of particles.

Students are also using several science and engineering practices

  • 3-5-SEP2.4: Develop and/or use models to describe and/or predict phenomena.
  • 3-5-SEP4.2: Analyze and interpret data to make sense of phenomena, using logical reasoning, mathematics, and/or computation.
  • 3-5-SEP5.2: Describe, measure, estimate, and/or graph quantities such as area, volume, weight, and time to address scientific and engineering questions and problems.
  • 3-5-SEP6.2: Use evidence (e.g., measurements, observations, patterns) to construct or support an explanation or design a solution to a problem.
  • 3-5-SEP8.4: Obtain and combine information from books and/or other reliable media to explain phenomena or solutions to a design problem.

The lesson focuses on one disciplinary core idea

  • PS1.A Structure and Properties of Matter
    • Matter of any type can be subdivided into particles that are too small to be seen, but even then the matter still exists and can be detected by other means.
    • The amount (weight of matter) is conserved when it changes form, even in transitions where it seems to vanish.


Photo by Laker on

On August 31 we investigated what happens to materials when they are crushed.

Making Predictions

I asked students to think about a soda can that gets crushed and a piece of paper that gets torn into 100 pieces. I asked them to answer these questions in their notebooks.

When a material changes shape,

  • Is it still the same material?
  • Does the amount of the material remain the same?
  • Why do you think so?

Students compared their answers in groups. We found that we had different ideas about what happens to the amount of materials when it is crushed.

Carrying Out the Investigation

We had already decided the class before on things we would test in our crushing experiment. All groups tested an aluminum can, a piece of paper, and a cookie. Then they chose two items from other available materials, such as aluminum foil, wood sticks, and cardboard.


Cookie before crushing
Cookie after crushing

Students observed the properties of materials before and after crushing and weighed the materials before and after crushing. They gathered their data.

Analyzing and Interpreting Data

On September 1 we began analyzing our data to make sense of what happened during crushing. Groups looked for patterns in the property and weight data and figured out what those patterns meant.

I introduced the concept of evidence. We talked about the difference between evidence and opinion. We discussed examples of evidence. Evidence is important because scientists use evidence to make claims. I told the students that, as scientists, they would be using evidence to make claims. Scientists decide which claims are best by arguing from evidence. We discussed how scientists support or refute claims.

Creating Claim, Evidence, and Reasoning Collaboratively

We practiced making a claim and supporting it with evidence and reasoning. We made a claim about what happened to the type of material before and after crushing. We decided that the type of material was the same before and after crushing. We identified evidence from our investigation that supported the claim. For example, the cookie was black, rough, and dull before and after crushing. The foil was silver and shiny before and after crushing. Our reasoning was that materials have certain patterns of properties. If the material is the same, the properties should be the same.

We did notice that some properties could be different before and after crushing. For example, texture can change. The aluminum can was very smooth before crushing. Some students crushed their cans by stepping on them on the sidewalk. The rough sidewalk imprint changed the texture of the can.

Next Steps

Our next step in this investigation will be to make an evidence-based claim about the weight of the material before and after crushing. I’ve noticed in my circulating the room that some students have data that will support that the weight is the same before and after crushing, while others have data that will refute that claim. When we continue this investigation, I plan to have groups assemble their own claims, evidence, and reasoning. Then they will compare their claims, evidence, and reasoning to other groups, decide if they support or refute the claim and provide evidence and reasoning for that position. This will be our first scientific argument.

Before we have our scientific argument, I will show this video to review what a scientific argument is.

I will scaffold students’ scientific arguments with an organizer.

I added the level of certainty information to see how students respond to the discrepancies in their data and to connect to the video content. From my observations, I noticed there were issues with taring the scale that led to inaccurate measurements.

After each group fills out their organizers, they will compare their arguments with another group by trading papers. Then they will use sentence starters to give feedback about the argument.

Evaluating the Argument

First, they need to evaluate the argument.

  • Is the evidence relevant to the claim?
  • Do you trust the evidence?
  • Are there gaps in the cause and effect reasoning?
  • Is there another possible explanation?

Responding to the Argument

If they disagree with the argument they can:

  • Ask a question about the reasoning
  • Offer different reasoning
  • Offer a different claim. 
  • Look for other reasons for the evidence. 
  • Compare claims with known scientific facts. 
  • Make sure that all data is included.

If they agree they can:

  • Give additional evidence or reasoning

Supporting Student Responses

To support their responses, I offer some sentence starters.

To refute a group’s claim, evidence or reasoning they can:

  • (ask a question) Why did you think that?
  • (offer another reason or claim) I think that.. 
  • (look for other reasons) I think that happened because…
  • (compare to facts) I read (or was told)… 
  • (include more data) This data (share the data) refutes your claim.

To support a group’s claim, evidence, or reasoning they will

  • (Add more evidence or reasoning) My data showed that…

I am looking forward to my students’ first scientific argument. Stay tuned…

Systems Models

Photo by Andrea Piacquadio on

Our garbage journey continues! On August 27 students made individual predictions about what will happen to the properties of the four rubbish materials (apple, banana, plastic, foil) over time. They also predicted what will happen to the weight of their landfill bottle over time. Half of the students had created a closed system and the other half had created an open systems.

I introduced the idea of system models, which they had used earlier. Scientists make system models to show the important components of the system and how those components interact. Students were asked to create a model that would include the system components and tell the story of what is going on in the bottles at each time point. Today we create the model for time point 1. The model for time point 1 includes a group prediction of what will happen to the rubbish materials.

On August 30 students examined one of the group’s models to notice its features. Models are thinking tools that scientists use to describe, explain, and predict. We will use our models to keep track of how the system changes. Later, we will use the models to support our explanations of the phenomenon.

Developing and using models is one of the science and engineering practices. We discussed how we are using these practices because we are scientists. Then we reviewed the list of 8 science and engineering practices:

  • Asking questions and defining problems
  • Developing and using models
  • Planning and carrying out investigations
  • Analyzing and interpreting data
  • Using mathematics and computational thinking
  • Constructing explanations and designing solutions
  • Engaging in argument from evidence
  • Obtaining, evaluating, and communicating information

We noticed which of these we have already used in science class. We have already used at least 3 of these!

We went back to our questions to pick another thing to investigate.

Our big question is How does the rubbish system work? One component of the rubbish system is a rubbish truck. What happens in a rubbish truck?

We watched this video clip about what happens in a garbage truck. The rubbish truck crushes materials. I asked What happens to materials when they are crushed? Does the kind of material change? Does the weight change? How could we investigate this in our classroom?

Students suggested we could weigh things before and after crushing them to see what happens to weight. Then we brainstormed ideas of what we could crush. Students contributed ideas and then we narrowed the list down to items that were things easy to get and safe. We decided on cardboard, paper, wood sticks, soda can, and aluminum foil.

The last activity for the day was an exit slip that asked students about the landfill bottle investigation. Students were asked to describe the system they were investigating, its components, the data they were collecting, and what questions the investigation will help answer. I collected these formative assessments.

Upon reviewing these assessments, I found that many students did not use the concepts of systems and components correctly yet. I plan to add an additional activity to reinforce this idea before we use systems again in class.

Model Landfill Bottles

Image from

On August 26 we started the major investigation of the unit. To answer the question of what happens to our garbage, students made six model landfill bottles. Students had collaboratively decided the components to include in the bottles the day before this activity. They included banana, apple, aluminum foil, and a plastic spoon in their bottles, along with soil and water. The spoons were identified as compostable spoons, which were the ones that come with the school lunches. Students will observe the bottles for a few weeks to look for changes in the properties of the materials over time.

I asked the students to predict what will happen to the materials in the bottles. Students said the materials would break down and turn into compost. I asked if they thought that would happen if the bottle were closed or open. Many students thought that the materials in the closed bottle would not break down. This gave a reason to compare open and closed systems. We left 3 bottles open to the air, but we did put a screen over the top of the bottle to prevent geckos from getting in the bottles. We closed the other three bottles. Now we have an open system and a closed system to compare. Systems and system models is a focal crosscutting concept for this lesson.

We have to wait to see what will happen. Next class we will create our group models for these systems.

Crosscutting Concept of Systems and System Models

Students should begin using the systems and system models crosscutting concept in K–2. According to the Next Generation Science Standards Appendix G, K–2 students should use the idea that “systems in the natural and designed world have parts that work together.” In 3–5, studentsʻ use of the idea gets more nuanced and they realize that “a system is a group of related parts that make up a whole and can carry out functions its individual parts cannot.” In phenomenon-based science teaching, systems and system models is a foundational crosscutting concept that students use to understand phenomena.

We conducted a formative assessment of the systems and system models concept in the context of the rubbish system by asking students what would happen if a component were missing. Students were also asked to give an example of a different system, to identify its components, and to describe how the components interact. Many students struggled with this assessment and were unable to identify a system, so I planned some additional instruction to provide additional support for this concept.

We began the next class with a definition and an example of a system. Then students were asked to decide which objects were examples of systems. I purposefully chose objects that were relevant to our local context in Hawai‘i.

I also asked students to explain how they decided if something was a system. I circulated the room, read and listened to their responses to see where they were with this concept. Several students were still struggling with the systems idea. I decided to do a whole class poll for a few of the things to see which students thought they were systems. I asked students who thought the gecko was a system to raise their hands and asked for someone to explain why. Most students understood that a living thing is a system with many parts. Next I asked who thought a pile of sand was a system. None of the students did.

I knew based on my observations that many students had not identified several things as systems that were systems. I shared the answers with students, which showed that all things except the pile of sand, laundry, and nails were systems. Next, I asked students which answers surprised them. One student said he was surprised that a coconut was a system. I asked the students what a coconut was. They replied that it was a seed. I asked if a seed had a job and they knew that a seed grew into a new coconut tree. Would the seed grow if one of its parts was missing? Then we could agree that a coconut was a system.

We went through several examples from the surprises and for each one, we collaboratively decided if it had parts that interacted. Hopefully this will help more students understand the systems concept. We will see as the unit progresses and students gain more experiences using the systems concept. We will continue to monitor students’ understanding and use of the systems and systems model crosscutting concept.

Creating the Driving Question Board

On Monday we began to build our driving question board. First we reviewed rubbish systems by building system models and comparing them. Students cut out images and arranged them into a system model for a rubbish system in the school or community. They compared the model to the home rubbish system model we had constructed the previous class. Here is one example of a system model for the rubbish system. We identified similarities and differences among the rubbish systems.

Next, Students took out the sticky notes that they had written their questions on. I asked them to individually decide which questions we could answer in science class. Then they talked with their groups to decide which questions we should answer in class. Each group put their sticky notes on a piece of chart paper at the end of class.

After class, I examined the questions and created the logical categories that are shown in the Google Jamboard.

Questions in logical categories

I thought about how these questions could lead into the investigations that I had already planned for this unit. Because the rubbish system is very different here than where the curriculum was developed, students had questions that are not addressed in the curriculum. For example, students had many questions about H-Power and generating electricity. I will add content to the unit to address theses questions.

The trash materials category (in blue) is the most closely connected to properties of materials. I will use this category to transition to the next lesson where we will look at changes in properties of materials in a landfill or compost. The question “Can all trash be made into electricity?” is an opportunity to talk about which materials go to H-Power and which do not go to H-Power. Once we have identified the materials that do not go to H-Power (commercial food waste, yard trimmings, metal, cardboard, etc) we can talk about why. The why is because of the properties of those materials.

Describing the ‘Ōpala System

Photo by Magda Ehlers on

In the homework from the last lesson, students were asked to identify items that went in the rubbish at home, show what categories these items fit into, and identify the properties of the items. In class, students shared their findings to notice similarities and differences in how families get rid of rubbish.

We used sticky notes and arrows to build a visual display of the rubbish system. Our display showed how the rubbish moves from one place to the next until it reaches the waste-to-energy plant and the landfill.

Next, students worked in groups to build similar models for school and community rubbish systems. Students talked about the components of each system and how the components work together. They discussed how the systems are similar and different.

This experience was the studentsʻ introduction to systems. We built on this to introduce the crosscutting concept of systems and system models and discuss how this crosscutting concept helps us think about and understand phenomena.

Structuring science lessons with CCCs

In the quest to shift instruction to be NGSS-aligned, the crosscutting concepts have gotten the least amount of attention. Most curriculum and instruction focuses on the science and engineering practices rather than the crosscutting concepts. Although the focus on the practices makes sense because these are the things scientists and engineers do, another alternative is to focus on the crosscutting concepts to emphasize how scientists and engineers think.

CCCs are the Thinking Tools of Science

The crosscutting concepts are the thinking tools, or cognitive heuristics of science. How can we use these cognitive heuristics to structure teaching and learning? In Ambitious Science Teaching, the authors presented a three-part strategy for whole-class discussions. I noticed that each part aligned with a different kind of crosscutting concept. The first step focused on observing Patterns. The second step asked students to make inferences about Cause & Effect. The third step asked students to apply their new knowledge to the anchoring phenomenon in a System Model. The diagram below shows these three steps using a crosscutting concept model that I presented in a previous post, which evolved from a model of the crosscutting concepts created by Rehmat et al. (2019).

Using CCCs to structure a discussion (Andersen, 2020)

What does this teaching structure look like in practice?

PART ONE: Students identify the patterns in the focal phenomenon through a common experience of the phenomenon. Teachers engage students in a discussion about what they observed. This step elicits student knowledge and provides motivation to learn.

PART TWO: Students make inferences about the cause of the effect that they observed. They examine new science ideas. Students figure out how the science ideas explain the phenomenon and the patterns they saw. This step helps students gather evidence of the explanatory mechanisms within the phenomenon.

PART THREE: Students apply the science idea to the anchoring phenomenon that is the focus of the unit. This step engages students in modeling an explanation for the phenomenon.


Notice that in each of the three parts, we focused on a different set of CCCs. Part one uses noticing (patterns), part two uses sensemaking (cause and effect), and part three uses modeling (systems and system models).

Letʻs look at an example of this in practice. Consider a 5th grade lesson in which students examine why some stars are brighter than others.


The constellation Pleiades or Makaliʻi (Public Domain, NASA)

Students look at a section of the night sky and look for patterns. They notice that some stars are brighter than others. They notice that the sun is brighter than all of the stars. Students discuss why this might happen.


Students investigate cause and effect relationships related to the brightness of stars. They examine how the apparent brightness of a flashlight varies with how far away the flashlight is from us. Students identify a cause and effect relationship between distance and apparent brightness (i.e., farther away flashlight appears less bright). They also identify that bulb rating affects apparent brightness (i.e., bulbs with higher lumen ratings can appear brighter from farther away than bulbs with lower lumen ratings). Now students have two cause and effect ideas to use to explain variations in star brightness.

Simple spreadsheet of star data (Lori Andersen)


Students apply these ideas to the anchoring phenomenon. They use a simple spreadsheet to examine data for the 20 brightest stars (distance from earth, luminosity, apparent brightness). They compare pairs of stars and figure out if the cause and effect ideas can explain which one appears brighter. Students model the system of star and observer with a new conceptual model. They determine that two factors affect apparent brightness: luminosity and distance from the observer. A star that is closer might appear brighter, but a farther away star can appear brighter if it is more luminous.

Cause and effect diagram (Lori Andersen)

Connecting the Lesson to the Anchoring Phenomenon

A summary table is a structure for whole-class sense making that can help students understand how each lesson contributes to understanding an anchoring phenomenon. Class discussions culminate in consensus about what should go in the table.A summary table helps students keep track of the ideas they develop through each activity as they develop a complete model for the anchoring phenomenon. The entry in the table represents the lesson that was describe above.

Summary Table Example


(What we did)
What we observed

What we learned

(Cause of the pattern?)
How it helps us understand?

(System model)
We observed the brightness of stars in the night sky and examined data about distances, magnitude, and, luminosity.Some stars are brighter than others. Stars are much farther away than the sun. Stars are a large ranges of distances from Earth.Many bright stars are closer to earth than other stars, BUT some are not. Some bright stars are farther away from Earth and more luminous.Star brightness is affected by two things:
(1) how much light the star emits, and (2) how far away the star is from Earth.
Summary Table Example

NSM Framework for CCCs

The diagram illustrates the larger model of all seven CCCs with three functional groups — Noticing, Sensemaking, and Modeling. The three-step sequence in this post provides a way to use these three groups in lesson design and create a focus on the thinking tools of science. Of course, the science and engineering practices and the disciplinary core ideas are also integrated in the lesson, which makes it three-dimensional. A focus on modeling makes it easy to integrate many practices (e.g., Passmore et al., 2017). In this way the Noticing-Sensemaking-Modeling framework is an alternative teaching structure that shifts the emphasis from the science and engineering practices to the crosscutting concepts, and from a focus on what scientists and engineers do to how they think and decide what to do.

Related posts

The lesson in this post is part of a larger unit on fifth grade Earth and Space Science. You can find out more about this unit on other posts:

Focusing a Crosscutting Concept Lens

In previous posts, I’ve written about integrating the crosscutting concepts (CCCs) in curriculum. The CCCs are a set of thinking tools, or epistemic heuristics, for science. Each CCC can be imagined as a lens through which we examine phenomena. Each lens reveals a different aspect of the phenomenon that should be included in an explanation of how the phenomenon works. In this post, I present a way to coherently integrate the CCCs into a curriculum unit.

I’ve used my graphic organizer to identify how each CCC applies to the phenomenon. The figure below is for the phenomenon of Makali’i rising at sunset each November, which is an indication for the start of the Hawaiian new year. In this post I will illustrate how to weave the CCCs into instruction over the course of a unit. Each of the CCCs is introduced in the unit as their investigations reveal related aspects of the phenomenon.

Systems and System Models is the Foundation

A key feature in the unit is student modeling. Systems and System Models is the foundational CCC (blue oval in the figure). At the beginning of the unit students create a system model that reflects their initial understandings. The model should include the important parts and how the parts interact. Students revisit the model two more times in the unit, at the middle and near the end. In the middle of the unit students refine the model using evidence from their investigations. Near the end of the unit students refine the model again to integrate their new understandings and explain the anchoring phenomenon. These refined models should address more CCC elements.

Begin Modeling with the Basics – Patterns and Cause & Effect

At the beginning, modeling should focus on the two first-order CCCs – Patterns and Cause & Effect (pink ovals in the figure). Students identify patterns in the phenomenon and attempt to explain the cause of the patterns. They do not yet know the cause and effect relationships that explain the phenomenon. This is a good time to elicit students’ ideas and create a class list. Teachers can offer sentence starters for students to record their ideas about the cause and effect relationships. After individual think time and small group sharing, teachers can gather ideas from the whole class into a list that is a class resource for modeling.

Next, students work in small groups modeling the phenomenon. Teachers can ask questions that help students use the other CCCs and focus their thinking. Based on the ideas a student has, teachers can focus a student’s thinking on a specific part of the phenomenon using focusing questions.

Focus Student Thinking with Remaining CCCs

The teacher should have a list of questions written in advance that target each of the CCCs as they apply specifically to the anchoring phenomenon. Let’s look at examples for the phenomenon of the rising of Makali’i. STEM Teaching Tool #41 is helpful for creating good focusing questions.

Scale, Proportion, and Quantity

  • Can an observer on Earth see the cause of the changes in the constellations that we see?
  • Is the cause too large or does it take too long to see directly?
  • How can a model make this cause easier to see?

Stability and Change

  • What explains why we see different constellations over a year?
  • What explains why the same constellation returns every year at the same time?

Energy & Matter

  • How does energy (light) travel in this system?
  • What causes an observer to see a constellation?

Structure & Function

  • How do the spatial relationships among the parts of the system cause the observer to be able to see a constellation?

Teachers should select which questions to ask based on what ideas students are trying to express in their models. The purpose of questioning is to elicit what students already know and help them express their ideas in models. The questions should not be used to try to change students ideas at this point. The teacher needs to use their judgement to determine which questions will help student thinking and which questions are not productive at this point in the unit.

Revising Models After Investigations

At the middle and near the end of the unit, students revisit their models to improve them. The focusing questions listed above can be refined to ask students to address how new evidence might be included in their models. For example, in the Makali’i unit students learn how Earth’s rotation makes the sun and stars appear to move over the day and night. They learn how the same motion can look different from different frames of reference. A person sees the Earth as stationary and the stars moving, while a person in space sees the stars as stationary the Earth rotating. Teachers can revise the focusing questions to help students examine how this finding affects their models. Here are some examples for two CCCS.

Stability and Change

  • How does the Earth’s rotation explain why our view of the sky from Earth changes?
  • How does the Earth’s rotation explain why constellation rise and set each evening?

Structure & Function

  • How does the Earth’s rotation affect our ability to see a constellation from Earth?

These revised focusing questions help student think about how to integrate their new knowledge into their models.

In this way, we can strategically integrate all the CCCs through iterative modeling and discourse tools. It may be that some CCCs are not helpful for certain phenomena. It may be better to introduce some CCCs later in the unit rather than at the beginning. Those decisions would be made on a case-by-case basis.

What do you think about these ideas? Let me know in the comments or on Twitter.

Transforming a Physics Lessons about Wave Properties

Are you transforming your physics course to NGSS? I took an old lesson of mine about properties of waves and transformed in to a phenomenon-driven storyline. The original activity was an inquiry-based lesson on wave properties. You can find it on the PhET website. I wanted to update this lesson to align with the NGSS…

Developing a Particle Model of Matter

On September 15, we started Lesson 2-3 of The Garbage Unit. This lesson develops the idea that solids and liquids are made of particles and uses this idea to explain sugar dissolving in water. The day before this lesson, students made predictions about what happens to sugar when we dissolve it in water. Most students…


On August 31 we investigated what happens to materials when they are crushed. Making Predictions I asked students to think about a soda can that gets crushed and a piece of paper that gets torn into 100 pieces. I asked them to answer these questions in their notebooks. When a material changes shape, Is it…