Day 1 Physical Vs Chemical Changes
Lesson 14 of 19
Objective: SWBAT to differentiate between a physical change and chemical change.
5e Lesson Plan Model
Many of my science lessons are based upon and taught using the 5E lesson plan model: Engage, Explore, Explain, Elaborate, and Evaluate. This lesson plan model allows me to incorporate a variety of learning opportunities and strategies for students. With multiple learning experiences, students can gain new ideas, demonstrate thinking, draw conclusions, develop critical thinking skills, and interact with peers through discussions and hands-on activities. With each stage in this lesson model, I select strategies that will serve students best for the concepts and content being delivered to them. These strategies were selected for this lesson to facilitate peer discussions, participation in a group activity, reflective learning practices, and accountability for learning.
The Matter and Energy unit focuses on the impact of temperature and pressure on solids, liquids, and gases. Students have multiple opportunities to develop an understanding that matter cannot not be created nor destroyed, only change. Through investigations of objects and substances, students identify materials by their properties, states, and determine if changes made to them are physical and chemical. Additionally, investigations include identifying materials that dissolve, mix, and change form and create a new substance. Students demonstrate their understanding by developing and using models, planning and carrying out investigations, constructing explanations, and using mathematical and computational thinking.
The Day 1 A Physical vs Chemical changes takes places over the course of two days. I begin by engaging students as a whole class. We identify ways to change the paper and test them out. Then, we discuss the changes we make and classify each change to the paper as either physical or chemical. I explain the differences between physical and chemical changes and have students create a foldable, which they use as they rotate through stations. While at each station, students are making changes to materials to determine the type of change they observe: physical or chemical.
Next Generation Science Standards
This lesson will address the following NGSS Standard(s):
5-PS 1.3 Make observations and measurements to identify materials based on their properties.
5-PS 1-4 Conduct an investigation to determine whether the mixing of two or more substances results in new substances.
Students are engaged in the following scientific and engineering practices
2.) Developing and Using models: Students use a variety of models throughout the investigation and test each one to determine if a physical or chemical change has taken place.
4.) Analyzing and interpreting data: Students analyze their observations to make sense of the kind of changes that occurred.
The Day 1- A Physical vs Chemical Changes lesson will correlate to other interdisciplinary areas. These Crosscutting Concepts include:
2.) Cause and Effect: Students identify and explain the change made to materials. They gather evidence by conducting several investigations to support kind of changes that took place.
Disciplinary Core Ideas within this lesson include:
PS1.A Structure of Matter: Measurements of variety of observable properties can be used to identify particular materials. (Because matter exists as particles that are too small to see, matter is always conserved even if it seems to disappear.)
Importance of Modeling to Develop Student
Responsibility, Accountability, and Independence
Depending upon the time of year, this lesson is taught, teachers should consider modeling how groups should work together; establish group norms for activities, class discussions, and partner talks. In addition, it is important to model think aloud strategies. This sets up students to be more expressive and develop thinking skills during an activity. The first half of the year, I model what group work and/or talks “look like and sound like.” I intervene the moment students are off task with reminders and redirecting. By the second and last half of the year, I am able to ask students, “Who can give of three reminders for group activities to be successful?” Who can tell us two reminders for partner talks?” Students take responsibility for becoming successful learners. Again before teaching this lesson, consider the time of year, it may be necessary to do a lot of front loading to get students to eventually become more independent and transition through the lessons in a timely manner.
I begin holding up a piece of paper and asking students, "who can identify this piece of matter I am holding up?" A student shares, "paper." I continue saying, "now that we have identified this, what are some ways we can change it?" Many hands are raised and I call on students to share. Students suggest to bend it, fold it, rip it, and shred it. As they share these suggestions, I carry out each idea so they can visually see the change that has taken place. I ask them: "Do I still have paper? Even though I changed the paper in a variety of ways, am I still left with paper?" I ask this because I want them to recognize that the paper's shape and size changes, but I still have paper. And it could be somewhat reversible.
After changing the paper in the ways they suggest, I ask them, "is there anything else that would change the paper?" Many students pause and a few hands go up. One idea is wetting it and another idea is burning it. Again, I carry out their idea; I wet the paper and place it next to the other pieces of paper I changed moments ago.
Then I move on with the next idea, burning it. I say, "So, how many of you agree that burning the paper will change it?? Many hands raise and I hear a student say aloud, "are you really going to burn it?" I say yes and then follow up with safety rules. I tell them, they are not to do this at home and show them a pan of water that I am using to place the paper in immediately following the task. I light the small paper and let it burn for about 3 seconds and quickly place it in the pan of water. While I wait for it be completely cooled off, I ask the students, "What do you think you are going to see?" I want students to think about how this paper changes compared to the changes I made to the paper by bending it, folding it, etc. I safely remove the burned paper from the pan of water. I hold it up and ask: "What do you notice about this paper now?" I hear many students say, "It's burnt." or "It's brown."
Noting their observations, I ask them: "Is the change I made to the paper this time (lighting it on fire) seem different than last time when I was bending, folding, or ripping it? What makes this change different from earlier? Did the shape, size, texture change? What about the color?"
By asking these questions, I am guiding students to discover that two different changes have occurred. I continue asking: "With the first set of changes to the paper (bending, folding, ripping, we said, we still have paper. we could reverse it and put it back together. But what about this burned paper? Can we do that? Why or Why not? Is there something new about this paper? (I am leading them into recognizing the burned paper has new substance on it and when a new substance is created as a result of the changes made, it is a chemical change.
I explain to them, "we made changes to this paper, however, the changes we made are two different kinds. One is a physical change and the other is a chemical change." Without telling them which change took place in each scenario, I move on by providing them information about each kind. At the end of defining each type of change, I come back to our engage activity where students apply this new information to determine which paper went through a physical change and chemical change.
Distinguishing Between Physical Change and Chemical Change
Once we identify two kinds of changes in matter, physical and chemical, I move onto defining and explaining the differences. I provide them this information before so they are better prepared to identify changes as they investigate different interactions of matter at each station.
We reflect on the changes we made to the paper and begin discussing properties to describe the changes made to the paper at the start of the lesson. I project each term and characteristics on the board. As I review them, I ask my students to create a foldable in their interactive notebook to define each word.
Connecting Vocabulary to Engage Activity
After distinguishing these terms, I go back to the papers and ask them to think about the information about each kind of change we have discovered. We apply the information by re-examining the changes to the paper and discussing each term with our new knowledge. Through some discussions, we determine the paper that was bent, folded, ripped, etc., is a physical change because only the shape and size changed, we still have paper and can reverse these changes. For the burned paper, we determine it went through a chemical change because we created a new substance on the paper which is irreversible.
With this understanding, I share with the students that they are using their foldable as they go through each station. It serves as a reference when they have to conclude if the changes they observe at that station are physical and chemical.
Preparing to Investigate
After distinguishing between physical and chemical changes, I hand out an investigation packet and then bring their attention to our standards board. I ask a student to read our task for today.
"Today we will rotate through six different stations carrying out investigations that cause changes to matter. We will examine these changes and determine if a physical or chemical change has happened."
After reading it out loud, I bring their attention to the six stations and task cards set up around the room:
- Eeewww...What Happened to My APPLE?,
- YAY for Clay!,
- Yikes!...Why Am I Growing?
- Whoa...Why is My Water Red?,
- Hmmm...Little Miss Muffet Sat Eating Her... Milk and Vinegar?
- Oh no...I’m Melting! What Happened to My Cup?
I tell them they are working with their group as lab rats at the first five stations, and the sixth station is a demonstration conducted by me (teacher) since the chemical, acetone, is used. I selected these investigations because students really need to think about the changes that happen as some of these changes may be misinterpreted.
All stations begin the same- reading the station card directions, setting up their recording packet, and writing a prediction about the outcome of the item undergoing change. Once they read the task card directions, the lab rats' director leads the group to complete the procedure . After completing their task, students observe changes, and record their findings. I remind them to that as they record observations to write exactly what they noticed. I tell them to think about what properties of matter changed...size, shape, color, etc? What changed about it? and to be specific.
Once all stations are reviewed, I direct each group to a station and tell them to begin. They work as lab rats, follow the directions as they perform the procedure at each station. I give them about seven minutes at each station. If more times is needed, I give each group a tray where they place their sample aside to allow time for each item change. I tell them they can come back to it and make observations after going through the remaining stations. (I use a timer to keep everyone on task.) I continue moving throughout the room and checking in at different stations.
Checking In with Students
As they are performing their tasks, I circulate the room and observe the combinations and changes they are creating. I notice at the yeast, sugar, and water combination station, a little more time is needed than I originally stated to them, so I tell them I will bring the substance to them as reactions take place. As I make way to the Why is my water red station, I overhear students thinking the changes the water is a chemical one. I jump in with some questions to get them back on track about the type of change that took place. I ask them questions like: why do you think it is a chemical change? Let's look at our foldable notes. Do you still have water even though you added red powder to it? Do you think adding a substance to another substance make it chemical?" This was the misconception here. I ask them to recall our lesson on the water cycle earlier in the year as I want them to think about the process of evaporation. "So let's think about evaporation, when water evaporates does everything in it go with it?" A student responds: "No, only the water evaporates, everything else stays." I say, Ok, let's use that same thinking here. If we evaporate this water, will the red substance go with it?" With these questions, I am able to get students recognize the results are a physical change rather than a chemical one.
I make my way to the next station, Hmmm...Little Miss Muffet Sat Eating Her... Milk and Vinegar?. I observe them mixing milk and vinegar. As they are combining milk and vinegar, I note their astonished looks. They are amazed as they observe the changes to the milk and vinegar.
For the last one, Oh no...I’m Melting! What Happened to My Cup?, I have volunteers help me perform the procedure, but they need to wear safety goggles and gloves as we watch what happens to the cup when it is placed in the acetone solution. As a volunteer places it in the solution and their eyes become really wide because the cup shrinks.
Teacher side note: I suggest using packing peanuts rather than a styrofoam cup and/or pure acetone. I did not use pure acetone as I thought it would be too strong for the students; therefore, packing peanuts would have a better result with acetone(nail polish remover I used) I found this activity online.
Observing and Concluding
At the end of our investigation, I direct students to return to trays they put aside if they had to wait for a change to take place and have them note their observations. If time allows, after they finalize their observations, I have them engage in conversation of how the substances changed. I ask them to draw and record what they notice about the object. (If time runs out, I tell my students we will pick up with conversations tomorrow.)