Download Chemical and Physical Change

Primary Type: Lesson Plan
Status: Published
This is a resource from CPALMS (www.cpalms.org) where all educators go for bright ideas!
Resource ID#: 128975
Chemical and Physical Change
This yummy lesson on physical and chemical changes will require students to apply their scientific knowledge to a backyard treat.
Subject(s): Science
Grade Level(s): 8
Intended Audience: Educators
Suggested Technology: Computer for Presenter,
Internet Connection, Overhead Projector, Microsoft
Office
Instructional Time: 1 Hour(s) 30 Minute(s)
Keywords: Physical Change, chemical change
Resource Collection: FCR-STEMLearn Physical Sciences
ATTACHMENTS
CreateYourOwnLabRubric.xlsx
HeyHowDidyouDoThatPhysicalChemicalChangeQuizAnswerKey.docx
HeyHowDidYouDoThatPhysicalChemicalChangeQuiz.docx
LetsMakeSmoreChangesPhyiscalChemicalChangesLab.docx
LESSON CONTENT
Lesson Plan Template: General Lesson Plan
Learning Objectives: What should students know and be able to do as a result of this lesson?
Students will be able differentiate between physical changes and chemical changes.
Students will be able to identify that when matter is changed chemically, a new substance with new properties is produced.
Prior Knowledge: What prior knowledge should students have for this lesson?
Students should have the ability to identify some familiar changes in materials that result in other materials with different characteristics, such as plant decaying,
burning, rusting, cooking.
Students should have a basic understanding that matter can undergo a variety of changes.
Students should have a basic understanding that matter can change physically and chemically.
Guiding Questions: What are the guiding questions for this lesson?
What kinds of changes can matter undergo?
How do you know a substance only changed in its physical makeup?
What makes a substance change chemically as opposed to only physically?
If you are able to reverse a chemical change, how would you perform the reversal?
page 1 of 3 What is happening on a molecular level during that chemical change?
Are there any examples where it is difficult to figure out if there was a physical change or chemical change?
Teaching Phase: How will the teacher present the concept or skill to students?
Engage students with a brief demonstration of cutting paper, balling up paper, folding paper, and burning paper. Before performing each change, engage the students
with questions regarding what type of change will occur. Require specific answers that demonstrate their grasp of. Indicate if any of the changes you made have
resulted in new substances with new properties.
Other options include adding food coloring or sugar cubes to water. Allow the students to first see what change is about to be performed, then observe each change.
The teacher could then elicit explanations as to why it is that particular change.
An important part of the teacher demonstration would be to reinforce correct concepts and debunk misconceptions about chemical and physical change. It is important
to introduce or review atoms. Explain how small atoms are and that we are unable to see them with the naked eye. In addition, clearly define chemical change (the
atoms in the reactants rearrange themselves and bond together differently to form one or more new products with different characteristics than the reactants forming a new substance). One helpful demonstration uses a votive candle and a glass jar. Allow the candle to burn (sustained via chemical reaction), discussing the
how the wax, wick, and oxygen are reactants. Discuss the molecules that are changing and forming "something new." Place the jar over the candle; the flame should
go out. Allow for more discussion regarding what is needed for the candle to burn. What happens when it burns continuously? Inquire about where the wax goes? Into
what is it chemically changed?
After the demonstration is completed, separate students in groups (no more than 4 per group). Assign the groups either physical changes or chemical changes and
allow them time to review their textbook (or preferred resource) information regarding their assigned changes. Invite them to discuss amongst themselves and make
notes. After about 5-7 minutes, switch out group members ensuring an "expert" for each change is represented in each group. Allow each expert to present all the
information they have gathered (2-3 minutes).
Using the current groups or your own pre-assigned groups, direct students to gather materials for the S'more Lab. Review safety procedures and rules.
As the students begin the laboratory, the teacher will encourage students to observe and identify all physical and chemical changes during the entirety of the lab.
Once the lab is complete, allow students time to record findings and answer questions. Have groups exchange lab notes and review similar or different responses as a
class. Place chemical/physical changes on overhead and allow students to answer with either individual white boards or use desk surface if permitted. Review answers
as you go along for understanding.
Guided Practice: What activities or exercises will the students complete with teacher guidance?
The teacher demonstration and review of chemical and physical changes will be completed with teacher guidance. During this phase of the lesson, the teacher will
challenge students to be able to explain what is making a physical change occur as opposed to a chemical change. Students will generally understand that matter
undergoes changes, but usually need to be guided in their understanding as to why it undergoes these specific changes.
Independent Practice: What activities or exercises will students complete to reinforce the concepts and skills developed in the
lesson?
S'more Lab and Expert Groups will be conducted independently. The teacher will continue to use Socratic questioning and probing questions, but these activities will be
student-led.
Closure: How will the teacher assist students in organizing the knowledge gained in the lesson?
After students complete the the Create Your Own Lab Assessment, allow students to view the finished products with a gallery walk. Allow them to comment on their
peers' work and answer 3 questions regarding the lab.
1. What is a physical change?
2. What is a chemical change?
3. What is the difference between a physical and chemical change?
Summative Assessment
For homework, students will individually create a laboratory experiment that can be performed to demonstrate physical and chemical changes. The laboratory will
focus on providing evidence of no changes in the atoms or molecules of matter (physical change) versus the creation of new substances produced with new properties
(chemical change). (See Rubric)
Formative Assessment
During the introductory demonstration, the teacher will gauge the understanding of the class through Socratic questioning. The teacher will identify during this
assessment whether students have a clear understanding that:
Matter can undergo both physical and chemical changes.
When a physical change occurs, there is generally no changes in the structure of the atoms or molecules of the matter.
When a chemical change occurs, new substances with new properties are produced.
The "How did you do that?" Quiz on Physical and Chemical Changes (See Attachment) and laboratory activity will also help teacher gauge understanding and direct
learning and instruction.
Feedback to Students
Through the class discussion during the demonstration, the quiz, and laboratory activity, students will be provided with ample feedback to help them develop their
understanding and differentiation between chemical and physical changes. The quiz will be formally reviewed with students in class; have them provide answers as
you go through each question. During the discussion in the demonstration or quiz review, students will be encouraged to use evidence to defend or refute answers.
ACCOMMODATIONS & RECOMMENDATIONS
Accommodations:
Visual Lab: Allow students to perform lab step-by step visually using their prior knowledge to write and illustrate what is happening at each point or direction. This can
page 2 of 3 be done in lieu of doing the lab or as a precept for completing the actual lab.
Have students at home or in class write about their "ordinary" everyday activities agenda style and then next to each activity determine if the activity is a physical or
chemical change include the how.
In the interest of time perhaps the lab could be performed as a demonstration.
Extensions:
Provide students with materials to perform the lab at home and create a mini-quiz for parents to be returned completed with a signature.
Take students outside to take what may still be an abstract concept of physical and chemical changes and provide the real-life examples. (e.g.: the water cycle,
photosynthesis, breathing, cars driving)
Students can write about the chemical changes that occurred when the s'mores were digested in a story format. These may specifically be written about the
molecular changes from the marshmallow's point of view.
Suggested Technology: Computer for Presenter, Internet Connection, Overhead Projector, Microsoft Office
Special Materials Needed:
Dry erase boards (White Boards)
Dry erase markers
Burners
Votive candles
Matches
Small jar (to cover candle)
Marshmallows, chocolate, and graham crackers
Wooden skewers
Further Recommendations:
Pre-soak wood skewers in water for safety.
Additional Information/Instructions
By Author/Submitter
Note: do not define a physical change as a change that can be reversed. This provides a misconception with students that chemical changes cannot be reversed. This is
incorrect as chemical changes can, in fact, be reversed chemically.
The overall goal in middle school is to transition students into an understanding that a physical change does not change the structure of atoms or molecules, whereas a
chemical change will rearrange the bonds between atoms and produce new substances with new properties.
SOURCE AND ACCESS INFORMATION
Contributed by: Suwana Jean Janvier
Name of Author/Source: Suwana Jean Janvier
District/Organization of Contributor(s): Columbia
Access Privileges: Public
License: CPALMS License - no distribution - non commercial
Related Standards
Name
SC.8.P.9.2:
Description
Differentiate between physical changes and chemical changes.
page 3 of 3