Monthly Archives: August 2021

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.

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.

A Virtual Tour of the ‘Ōpala System

Today is the second day of Lesson 1-1 in the adapted Garbage Unit. Last class, students sorted the lunch rubbish and created categories. The categories this class created were food, paper, plastic, and cardboard. They observed the patterns of properties of materials in the rubbish. Today students made predictions about how those materials will change over time. We shared our predictions with each other.

To check some of our predictions and see where our trash goes, we took a virtual field trip. The ‘ōpala system is different than the garbage system in other places, so we adapted the unit by including videos that are locally relevant. For example, after sorting at homes or businesses, rubbish goes to the H-Power waste-to-energy plant rather than to a landfill. We gave students sticky notes to write down the questions they have. We told students that we would be using these questions to plan our investigations.

First, we showed a video clip from a science show for kids about waste-to-energy plants. (We started this video at 0:22 and ended at 1:57 to focus on content appropriate for elementary students.) We told the students that even though this video was made in Massachusetts, we have the same kind of waste-to-energy plant in Hawai‘i in Kapolei.

Next we showed the video clip that comes with The Garbage Unit about landfills (This video clip is 2 min 19 sec.) On O‘ahu, the ash from the burned rubbish goes to a landfill rather than trash going directly to the landfill. We do not explain this to the students yet, that will come in the next lesson when we create the system model.

We showed a third video clip from the local news about H-Power, which is the trash-to-energy plant in Kapolei. This clip features students explaining what H-Power is and how it benefits O‘ahu. We started the clip at 0:25 and ended at 2:32.

For homework, students were asked to notice things that go in the rubbish at home, draw and label these things, and place them in the appropriate category (food, plastic, paper, cardboard). For each category, students were asked to list some properties of things in that category. Lastly, students were asked to talk to their families about how they get rid of their rubbish. We will use this information to build a model of the ‘Ōpala system next class.

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!