Author:
Brenda Bush-Hanson
Subject:
Physical Science, Chemistry
Material Type:
Activity/Lab
Level:
Middle School, High School
Tags:
  • Chemical Change
  • Physical Change
  • Thinking Routine
  • License:
    Creative Commons Attribution Non-Commercial
    Language:
    English

    Physical and Chemical Changes Demo & Reflection

    Physical and Chemical Changes Demo & Reflection

    Overview

    Students will oberve nine systems performed by the instructor.  They will then use the four indications of a chemcal change to determine if each system represents a physical or chemical change.  Students will reflect on their learning using the thinking routine - I Used to Think... Now I Think.  

    Physical and Chemical Changes Demonstration & Thinking Routine

    Standard: NGSS and Iowa Common Core

    HS-PS1.B: Chemical Reactions - The face that atoms are conserved, together with the knowledge of the chemical properties of the elements involved, can be used to describe and predict chemical reactions.

    Scientific Practices: Constructing Explanations

    Crosscutting Concepts: Patterns

     

    Essential Question: How can you distinguish between a physical and a chemical change?

    Teacher Information:

    Review the background information with students before completing the demonstration.  It is a good idea to record the indicators of chemical changes on the board as you review the background information with the class.

    The demonstration can be performed in person and the students can complete the demo handout during the demonstration.  Another option is for the instructor to record a video performing the demonstration.  The video could be then be shared with the students in the LMS or some other online platform.

    Background Information:

    In chemistry, the term change can refer to both physical and chemical changes. In the simplest sense, a physical change is a change in the form of the original substance. A chemical change is a change in the composition of the original substance. A chemical change is also called a chemical reaction.

    Indicators of Chemical Changes

    • An unexpected color change
    • The production of a gas (bubbles form)
    • The formation of a precipitate (a solid is produced out of solution)
    • The release of energy (heat or light)

     

    Physical and Chemical Changes Demonstration:

    Options for the demonstration:

    1. The instructor will perform the demonstration in-person and the students will record their observations and conclusions on the handout.
    2. The instructor could create a video performing the demonstration and share the video with the students.  The students could complete the handout during class or at home.

    Essential Question: How can you distinguish between a physical and a chemical change?

    Learning Targets:

    I can identify the four indications of a chemical change.

    I can distinguish between physical changes and chemical changes.

    I will make careful and accurate observations to determine if a change is physical or chemical.

    I will record my observations, the type of change observed for each system, and my explanations in the data table.

     

     

     

     

     

     

    Physical and Chemical Changes Demonstration

    Purpose: To make careful and accurate observations in order to determine if a change is physical or chemical.

    A physical change is a change during which some properties of the material change, but the composition of the material does not change.   

    A chemical change is a change that produces matter with a different composition than the original matter.

     

    1. Observe the nine systems demonstrated by your instructor.

    2. Record your observations, the type of change observed for each system, and your explanations in the data table.

    Thinking Routine - I Used to Think… Now I Think…

    Purpose: What kind of thinking does this routine encourage?

    The I used to think...but now I think routine helps students to:

    • Reflect on their thinking
    • Connect to their prior knowledge
    • Explore how their thinking has changed
    • Talk about and make their thinking visible to others

    Teacher Information: What are some tips for starting and using this routine?

    Explain to students that the purpose of this activity is to help them reflect on their thinking about the topic and to identify how their ideas have changed over time.

    For instance:  When we began this study of physical and chemical changes, you all had some initial ideas about it and what it was all about. In just a few sentences, I want to write what it is that you used to think about physical and chemical changes. Take a minute to think back and then write down your response to “ I used to think…”

    Now, I want you to think about how your ideas about physical and chemical changes have changed as a result of what we’ve been studying/doing/discussing. Again in just a few sentences write down what you now think about physical and chemical changes. Start your sentences with, “Now, I think…”

    In a blended class, I would have the students complete this portion of the lesson on a Google Doc or using some other type of collaboration tool like Padlet.

    Purpose: What kind of thinking does this routine encourage?

    The I used to think...but now I think routine helps you to:

    • Reflect on your thinking
    • Connect to your prior knowledge
    • Explore how your thinking has changed
    • Talk about and make your thinking visible to others