Changing the Shape of Matter

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Objective

SWBAT prove that the mass/weight of matter is conserved, even when the shape of matter changes.

Big Idea

In this lesson, students begin by comparing physical and chemical changes. Then, students investigate how the shape of clay affects the mass.

Lesson Overview

Inquiry Based Instructional Model

To intertwine scientific knowledge and practices and to empower students to learn through exploration, it is essential for scientific inquiry to be embedded in science education. While there are many types of inquiry-based models, one model that I've grown to appreciate and use is called the FERA Learning Cycle, developed by the National Science Resources Center (NSRC):

1. Focus

2. Explore

3. Reflect

4. Apply

A framework for implementation can be found here

I absolutely love how the Center for Inquiry Science at the Institute for Systems Biology explains that this is "not a locked-step method" but "rather a cyclical process," meaning that some lessons may start off at the focus phase while others may begin at the explore phase. 

Finally, an amazing article found at Edudemic.com, How Inquiry-Based Learning Works with STEM, very clearly outlines how inquiry based learning "paves the way for effective learning in science" and supports College and Career Readiness, particularly in the area of STEM career choices. 

Unit Explanation

In this unit, students will begin by exploring the properties of matter. Then, the class will investigate the mass of matter before and after physical and chemical changes by conducting investigations and constructing graphs. 

Summary of Lesson

Today, I open the lesson by creating a physical and chemical change poster with students. Students then explore how the shape of clay affects the mass of the clay. At the end of the lesson, students reflect and apply their new understanding of the conservation of matter by sharing their findings and constructing bar graphs. 

Next Generation Science Standards  

This lesson will support the following NGSS Standard(s):

5-PS1-2. Measure and graph quantities to provide evidence that regardless of the type of change that occurs when heating, cooling, or mixing substances, the total weight of matter is conserved.

5-PS1-3. Make observations and measurements to identify materials based on their properties.  (lessons 1 & 2)

Scientific & Engineering Practices

For this lesson, students are engaged in Science & Engineering Practice:

Science & Engineering Practice 4: Analyzing and Interpreting Data 

Students represent data in graphs, analyze data, and compare and construct data. 

Crosscutting Concepts

To relate ideas across disciplinary content, during this lesson I focus on the following Crosscutting Concept: Crosscutting Concept 5: Energy and Matter 

Students observe the conservation of matter within a system by tracking the amount of matter before and after the shape of clay changes. 

Disciplinary Core Ideas

In addition, this lesson also aligns with the following Disciplinary Core Ideas

The amount (weight) of matter is conserved when it changes form, even in transitions in which it seems to vanish. (5-PS1-2)

Measurements of a variety of properties can be used to identify materials. (Boundary: At this grade level, mass and weight are not distinguished, and no attempt is made to define the unseen particles or explain the atomic-scale mechanism of evaporation and condensation.) (5-PS1-3)

Choosing Science Teams

With science, it is often difficult to find a balance between providing students with as many hands-on experiences as possible, having plenty of science materials, and offering students a collaborative setting to solve problems. Any time groups have four or more students, the opportunities for individual students to speak and take part in the exploration process decreases. With groups of two, I often struggle to find enough science materials to go around. So this year, I chose to place students in teams of two or three! Picking science teams is always easy as I already have students placed in desk groups based upon behavior, abilities, and communication skills. Each desk group has about six kids, so I simply divide this larger group in half or thirds. 

Gathering Supplies & Assigning Roles

To encourage a smooth running classroom, I ask students to decide who is a 1, 2, or 3 in their groups of three students (without talking). In no time, each student has a number in the air. I'll then ask the "threes" to get certain supplies, "ones" to grab their computers, and "twos" to hand out papers (or whatever is needed for the lesson). This management strategy has proven to be effective when cleaning up and returning supplies as well!   

Focus

40 minutes

Teacher Note on Weight vs. Mass: NGSS Standard 5-PS1-2 states, "Measure and graph quantities to provide evidence that regardless of the type of change that occurs when heating, cooling, or mixing substances, the total weight of matter is conserved." For the last four lessons of this Matter Unit, students change matter physically and chemically to see if the total mass (instead of weight) is conserved when the matter undergoes change.

If replicating these lessons, a teacher could have students find the total weight as stated in the standard instead of the total mass. However, the standards also specifically state, "Mass and weight are not distinguished at this grade level."

I personally overlooked this detail unintentionally mostly because I kept thinking: mass refers to the amount of matter in an object while weight is the measurement of the pull of gravity on an object.

Now that I look back on these lessons I think that measuring the mass (without heavily focusing on the distinction between mass and weight) makes more sense. Here's why: the definition of the Law of Conservation (found at Britannica Kids) says: Matter can be neither created nor destroyed. In other words, the mass of an object or collection of objects never changes, no matter how the parts are rearranged.

Matter Unit Lapbooks

To provide students with a method to keep track of their research and thinking during our unit on matter, I followed these steps to create lapbooks for each student. 

1. I folded each side of a file folder inward to create a booklet that opens from the center: File Folder.

2. Next, I made copies of Lapbook Templates on colored paper (purple, yellow, green, and orange). I made sure to have enough copies so that each student would have 4 graphs, 6 research notes, 8 investigations, 18 vocabulary words (9 sets of 2 words), and the 4 pictures.  I also copied the Other Research Pocket onto blue card stock paper so that students would have a place to put loose papers. 

3. Then, I stapled the templates into each lapbook: Inside the Lapbook.

4. Before starting our unit on matter, I asked students to help personalize their lapbooks. Students used a glue stick and tape to secure the blue research pockets on the back (Student Research Pocket Example). Then, they decorated the cover: 

 

Creating these lapbooks helps build excitement and student ownership!

Physical & Chemical Changes Poster

I begin today's lesson by creating a Physical & Chemical Changes Poster while we discuss examples of physical and chemical changes as a class. During this time, students also take notes in the research section of their lapbooks (Student Notes on Physical & Chemical Changes 1 & Student Notes on Physical & Chemical Changes 2). 

I explain and write at the same time (notes on physical changes in blue & notes on chemical changes in red to assist with the categorization of information): A physical changes is where matter changes shape or form, but the molecular structure stays the same. On the other hand a chemical change is when matter changes on a molecular level, resulting in the formation of a new substance.

Many physical changes can be undone. However, chemical changes involve the making or breaking of the bonds between atoms, therefore, they can't be undone.

To help students build a greater understanding, we discuss and list examples of each type of change. I draw pictures of each to make this activity more interesting and memorable. 

Physical: crushing a can, melting ice, chopping wood, dissolving salt in water, shredding paper

Chemical: cooking an egg, rusting nail, burning wood, digesting food, fizzing tablets

Teacher Note: After teaching this unit, I completed more research on dissolving salt in water. According to the following site, "There are many cases where the distinctions between physical changes and chemical changes are unclear." Dissolving salt in water is one of these cases! This would have been a great conversations to have with students. 

Vocabulary

Using the provided definitions on the poster, this is the perfect time for students to add physical and chemical changes to the vocabulary section of their lapbooks. Here are a couple student examples: Physical Change and Chemical Change.

Engage

For today's lesson, students change the shape of clay to see if the mass changes. I want to inspire interest in today's lesson and capitalize on student curiosity, so I start with a similar demonstration by weighing a piece of cardboard, ripping the cardboard up, and weighing it again. 

I get my Digital Scale & Piece of Cardboard. I hold up the piece of cardboard and ask students: How many grams do you think this piece of cardboard weighs? Student responses include 7, 5, 3, 26, 1, and 700: Beginning Cardboard Guesses. With a range of guesses from 1 gram to 700 grams, I realize that my students need a frame of reference. 

I pick up a glue bottle and measure to the mass: Mass of Glue Bottle. I share with the class: If a glue bottle weighs 127 grams, how much do you think a piece of cardboard weighs? 

This time, student guesses were more informed: More Informed Cardboard Guesses. I then weigh the piece of cardboard and announce the total mass of the cardboard to the class: 42 grams. 

I begin ripping the cardboard into pieces and I ask: What if I rip the cardboard up into smaller pieces? What do you think will happen? Turn and talk: will the cardboard weigh more or less? Student responses vary: Ripped Pile of Cardboard Guesses. Some students think it will weigh more. (The pie of cardboard appears to take up more space than the flat piece of cardboard.) Others think it will weigh a little less now that the  cardboard is in smaller pieces. There are also students that insist it will weigh the same (42 grams).

With such varied responses and unsure students, I'm so glad we're going to investigate this! To my students' surprise, I announce that we will be measuring the mass of the ripped up cardboard at the end of the lesson. Students respond, "Awe man!" This way, students can investigate the conservation of matter on their own during the clay investigation today. 

Explore

40 minutes

Getting Ready

To prepare for today's investigation, I set out the following items on the counter: 

Today, each group will be given a piece of clay. What questions are you interested in investigating?  It doesn't take long for a student to ask today's investigative question: Developing an Investigative Question.

Investigation Template

The class discusses and completes a new investigation template in their lapbooks. I model their thinking by projecting the following Teacher Model of the Investigation.

Question: How does the shape of clay affect the mass?

Observations (Before): Students agree that the same amount of clay should be weighed each time. They also come up with three different shapes: ball, flat, and roll. 

Observations (After): To prepare for recording investigation data, we draw a data table to collect the mass of each clay shape. 

Students can't wait to start investigating! 

Monitoring Student Understanding

Once students begin working, I conference with every group. My goal is to support students by asking guiding questions (listed below). I also want to encourage students to engage in Science & Engineering Practice 7: Engaging in Argument from Evidence

  1. What patterns have you noticed? 
  2. Why do you suppose ____? 
  3. What have you found so far? 
  4. Has your thinking changed? 
  5. What evidence do you have? 
  6. How did you decide _____?
  7. What conclusion can you draw about ____?

Student Conferences

During this conference, Conferencing with Students, I love watching how the process of investigating helps students build a better understanding of how changing the shape of matter does not change the mass. 

Here, Conferencing with Students 2, the students decide to try tearing the clay, just like the cardboard. Following this conference, I encourage the rest of the class to try other clay shapes as they finish. Others try ripping the clay as well. Some groups try a cube shape. 

Reflect & Apply

30 minutes

Sharing Findings

Now that students have built meaning and understanding by observing, questioning, and exploring, it is important to provide students with the opportunity to share their findings. For this reason, I invite students to complete their investigation conclusions and to share their findings with the class. Almost all groups found that each clay shape had the same mass. Here are a few examples of completed student investigations: 

 

Graphing

According to NGSS Standard 5-PS1-2, 5th grade students are expected to "measure and graph quantities to provide evidence that regardless of the type of change that occurs, the total weight of matter is conserved." For this reason, I ask students to complete a graph template in their lapbooks to represent their findings. 

I model how to label the x-axis with the clay types and the y-axis with the mass (Teacher Graph). I then explain how to determine the scale of their individual graphs using the highest data collected. For example, if their highest data point is 25 grams, they want to make sure that the scale counts by a number that allows them to graph up to 25 grams. Most students love graphing and can't wait to begin! 

Here are a couple examples of student graphs:

 

Ripped Cardboard Demonstration
To bring closure, I return to the Ripped Cardboard on Scale from the beginning of the lesson and I can't believe my eyes! The scale reads one gram heavier than before (43 grams instead of the beginning mass of 42 grams). This provides the opportunity to have a discussion about the placement of the cardboard on the scale and how classroom scales are often not as accurate as the highly sensitive scales in scientific laboratories.
Still, some students think that the cardboard actually weighs more ripped up and this demonstration only reinforces this belief, so I quickly grabbed three sheets of lined paper to demonstrate this concept once more. I first weighed the lined paper (Lined Paper Before). Then, I crumpled the lined paper up in a ball (Lined Paper After). This time, the demonstration went as planned and the line paper was 15 grams before and after crumpling it into a ball!