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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…

The Driving Question and Planning an Investigation

Photo by Sindre Stru00f8m on

Our next step is to identify the driving question for our unit. This is the first time that these students are creating a driving question board. We began by talking about what a driving question is—one big question that includes all the other questions or that is the big idea that all the questions would fit under. Students talked with their table groups about their ideas for a big question, then they shared with the class. The big question that emerged was How does the rubbish system work?

Next we talked about how scientists find answers to their questions. I asked students to talk with their table groups about when they had worked like scientists and how scientists find answers to questions. Students shared ideas such as research, observing, and investigating.

We then began planning our first investigation. I reminded students that scientists plan their investigations before they carry them out. Our big question is about how the rubbish system works. I shared some data about materials that do not go to H-Power, to connect to a student question from the driving question board, Can all trash be made into electricity?

I shared this data from the website on O‘ahu’s recycling.

O‘ahu 2019 recycling data (Source:

I told students that according to the website, these are materials that do not go to H-Power to be burned. I asked students why they thought we do not burn these materials. For example, why donʻt we burn metal? We discussed how metal melts rather than burns, so it cannot be burned to make electricity. Then we discussed how food waste and yard trimmings can be used to make compost and fertilize plants, which is why restaurants and hotels are required to compost their food waste. It is better for the Earth to reuse and recycle what we can rather than burn it.

I asked the students how they thought we could make a test landfill or a test compost and what different materials they thought we should investigate. We collaboratively developed a list of what to include in our compost bottles—soil, water, banana, apple, plastic spoon, and aluminum foil.

Next class we plan our investigation.

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.

Rubbish Sort

Tuesday was the first day of the ‘Ōpala unit. ‘Ōpala is the Hawaiian word for garbage and the unit is adapted from the NYU SAIL Garbage Unit, which is an Open Educational Resource. The Garbage Unit was awarded the NGSS Design Badge.

Locally, we use the word rubbish rather than the word garbage. The unit is place-based as we are studying our local ‘ōpala system. The unit is problem-based as students will be figuring out what happens to their rubbish and why it happens. In this phase of the unit, students have opportunities to experience the anchoring phenomenon. We engage students with the phenomenon of rubbish and we elicit their initial ideas. Students will later create a driving question board. During the unit the class will answer their questions through investigations.

Tuesday was the first day of our unit. Lesson 1-1 takes 4 days. The first activity was for students to sort items from the lunch rubbish into categories. I asked each group of students to observe a small pile of rubbish. I asked them how and why scientists make observations. They knew that scientists looked at things carefully to figure out how and why things happen. The students were tasked with sorting their rubbish pile into smaller categories.

Rubbish sorted into food and not food categories

Two kinds of sorting emerged. A few groups of students sorted their rubbish into two categories—food and non food. The rest of the groups sorted their rubbish into three categories—paper, plastic, and cardboard.

We talked about how scientists use patterns of properties to identify materials. The students wrote down the sorting categories and the properties of things in those categories in their science notebooks.

Tomorrow we will predict what happens to those categories of things over time in the rubbish and take a virtual tour of the ‘Ōpala system.

Starting a New Unit

Yesterday I met with my new science class for the first time and I told them that are helping me with my research on science teaching and learning. Their first assignment was to help me find out what they already know. As a formative assessment, students engaged in three learning activities similar to what they will do later in the unit.

Students were presented with three tasks. They were asked to observe substances before and after mixing, then explain if they thought a new substance was formed or not. They were asked to develop a model of how smell travels to your nose and use it to explain how smell travels and why they cannot see it. Finally, they were asked what would happen to the weight when something melts and to explain why weight changes or does not change.

The preassessment items are phenomenon-based and three-dimensional. They provide insight to studentsʻ use of important disciplinary core ideas, science and engineering practices, and crosscutting concepts.

Disciplinary Core Ideas

I learned about students prior knowledge of PS1.A structure and properties of matter. Items probed students knowledge of how to use properties to identify substances, determining if a new substance is formed when substances are mixed, how matter is made of particles too small to be seen, and about conservation of matter (for melting).

Crosscutting Concepts

I learned about studentsʻ prior knowledge of patterns as they used (or did not use) patterns of properties to identify substances. They also used cause and effect to explain what causes smell and what causes weight to change or not when something melts. They demonstrated their knowledge of systems and system models as they modeled smell and showed the components of a system (nose, smelly object, smell, air) and how they interacted to cause smell.

Science and Engineering Practices

I learned about studentsʻ abilities to use two practices—constructing explanations and developing and using models. Students constructed a model for how the smell of food travels to their noses and used the model to construct a written explanation.

This information will help me support students through the rest of the unit. Tomorrow we begin with a rubbish sort!

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…

Adjusting complexity of data with representations

In my last post, I pondered how to integrate skills across math, ELA, and science in a lesson about falling objects. The mathematics content quickly became a little complicated for fifth grade. What other ways can we represent data to make it more accessible?

My next idea was to look at a ball drop over a longer distance. I found a video of a ball dropped from the roof of a building that was a sample video in Video Physics from Vernier Software. I used Video Physics to mark the position of the ball in every 10th frame of the video. These marks are a visual representation of the data.

Sample video of ball drop with and without markings

Gathering evidence

Students can look for patterns in the spacing of the marks. They should notice the marks get farther apart as the ball falls. How is this evidence of the direction of gravity?

The person released the ball and it fell. The observation that the ball moves downward is evidence that some force pushes or pulls down. But what about after the release? Is that force still pushing or pulling down? How do we know?

The pattern of the marks gives us clues. The marks show the ball position at evenly spaced time intervals. The ball moves farther during each time. This means the ball is moving faster. What made it move faster?

Teacher content knowledge

Here is a little refresher about elementary physical science and the topic of forces and motion. Students learn about forces and motion in several grades.

  • In kindergarten, students explore the effects of different strengths and directions of forces on motion. They also compare design solutions for changing the motion of an object. (K.PS2-1 and K.PS2-2)
  • In Grade 3, students investigation the effects of balanced and unbalanced forces on the motion of an object. They also learn to use patterns of motion to predict future motion. (3.PS2-1 and 3.PS2-2)

Student inferences

In Grade 5, we ask students to transfer knowledge from their prior observations of contact forces (pushes and pulls) to a non-contact force (gravity). They should already know that to make something keep getting faster (accelerate) requires continued pushing or pulling in that direction from explorations in kindergarten and grade 3. Applying that to the falling ball, students can infer that something must be pulling or pushing the ball toward the ground to make it go faster.

Once students have made this inference, they are ready to learn about the concept of gravity. Gravity is different than pushes and pulls. The Earth pulls on the ball because the Earth is extremely large. The pull of Earth on objects is gravity.

When the person holds the ball, the forces are balanced. The upward force of the hands on the ball balances the downward pull of gravity. After the person releases the ball, the forces are unbalanced. The downward pull of gravity makes the ball speed up as it moves toward the ground.

The next step is for students to create an argument with grade-appropriate ELA skills. Those CCSS were listed in this post.

Did you find this post helpful? If so, let me know in the comments.