Primary Type: Lesson Plan
Status: Published
This is a resource from CPALMS (www.cpalms.org) where all educators go for bright ideas!
Resource ID#: 20148
Chemical or Physical Change? That is the Question!
Students will conduct an investigation on the effect of laundry detergent on water temperature, use technology to graph their data, and determine
whether a physical or chemical change occurred. Students will also read articles to gather evidence to write an evidence-based claim using the
CLEVER method.
Subject(s): Science
Grade Level(s): 8
Intended Audience: Educators
Suggested Technology: Document Camera,
Computer for Presenter, Computers for Students,
Internet Connection, Probes for Data Collection, Basic
Calculators, LCD Projector, Microsoft Office, GeoGebra
Free Software (Download the Free GeoGebra
Software)
Instructional Time: 2 Hour(s)
Resource supports reading in content area: Yes
Freely Available: Yes
Keywords: temperature, chemical change, physical change, CLEVER writing model, evidence, linear association,
nonlinear association, outliers, clusters
Instructional Design Framework(s): Guided Inquiry (Level 3)
Resource Collection: FCR-STEMLearn Physical Sciences
ATTACHMENTS
10 examples of Chemical changes.docx
Answer Key How does laundry detergent affect water temperature.docx
10 examples of Physical changes.docx
CLEVER Model Organizer.docx
CLEVER Model.docx
CLEVER Peer Review Worksheet.docx
CLEVER Rubric.pdf
How does laundry detergent affect water temperature.docx
Lab Report Rubric.pdf
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 to:
use at least three types of evidence from a media source and lab data to support their claim.
interpret whether a graph is linear or nonlinear.
identify clusters and outliers in graphs.
explain how temperature could cause a physical or chemical change.
Prior Knowledge: What prior knowledge should students have for this lesson?
page 1 of 5 SC.5.P.9.1: Investigate and describe that many physical and chemical changes are affected by temperature.
In addition, students should know:
rules for lab safety. The teacher can conduct a brief review using safety guidelines from The National Science Teachers Association.
what physical or chemical changes are. See the Stand Up, Hands Up, Pair Up activity in the Teaching Phase.
about temperature.
Students can Think-Pair-Share: think about temperature for 1 minute, pair up with their elbow partners, and share what they know about temperature. The
teacher should record some of these to eliminate misconceptions.
how to use a thermometer or temperature probe.
If students need more information or a review, direct them to the Wikihow article "How to Use a Thermometer."
Students should have some experience in using multi-sources as evidence to support claims in writing.
how to construct a scatter plot graph using Excel.
For a review on scatter plots, see the scatter plot page at iCoachMath.com or collaborate with a math teacher for ideas.
To learn about how to make these graphs on Excel, see the About.com tutorial.
Students should have some knowledge about outliers and clusters, positive and negative associations from data on graphs, and linear vs. non linear associations
from data on graphs.
The software GeoGebra is a user-friendly software that shows these distributions. Teachers and/or students can use the free tutorial on how to use GeoGebra
at http://wiki.geogebra.org/en/Tutorial%3AMain_Page.
Guiding Questions: What are the guiding questions for this lesson?
1. How does laundry detergent affect the temperature of water?
As more laundry detergent was added to 100 mL of water, the temperature of the solution increased.
2. Is the temperature change created by the addition of laundry detergent to water an example of a physical or chemical change? Explain your answer.
Physical change, because no chemical reaction is occurring (the powder doesn't change into something new, and neither does the water). Instead the molecules are
just arranged in a different way. In moving to their new arrangement, they either release or absorb energy.
Students can make a case for a chemical change because the laundry detergent contains chemicals that release heat when they dissolve in water. Heat is usually an
indicator of a chemical change. When chemicals combine in new arrangements, they often exchange energy. In this experiment, we discovered how dissolving the
detergent (solids) in water releases or absorbs energy. Teachers can also use the article "A Study on Chemical Contamination of Water Due to Household Laundry
Detergents" by Geetu Goel and Surinderjit Kaur, 2012, in The Journal of Human Ecology, Volume 38, Number 1, pages 65-69.)
3. How did the media sources on laundry detergent compare to the data collected in the lab?
Answers will vary depending upon the articles used and data collected. Students should find that the temperature increased as the amount of detergent used
increased. This will allow people to use cold water or cooler water with with larger amounts of detergent, because the detergent will warm the water. However, these
articles warn against using too much detergent because that will wash out the color and/or reduce the whiteness over time, making the clothes look dingy.
Teaching Phase: How will the teacher present the concept or skill to students?
1. Introductory Questions: The teacher will display the following two questions on the Smartboard or Whiteboard as a quick-write. The teacher will give students
3-5 minutes to write a response for both questions and randomly select 3-4 students to share their responses to each question.
1. What things in the world give off heat?
Possible answers include stoves, light bulbs, car engines, fires, the sun, volcanoes, friction (e.g., from rubbing hands together)
2. What causes the heat in these things?
Stoves and light bulbs use electricity to heat metal. In fires, a chemical reaction between the wood and air releases heat. The sun is hot because of nuclear
explosions that release heat. Finally, friction from rubbing hands releases heat by a simple mechanical process of rubbing molecules together.
2. Stand Up, Hands Up, Pair Up: The teacher will have have students review chemical changes and physical changes by using the Kagan strategy Stand Up, Hands
Up, Pair Up (see #13 in the linked document). The teacher will distribute cards with examples of chemical changes and physical changes. Students stand up, put their
hands up, and have three seconds to pair up with a partner. Once paired, students will identify if their card describes a physical or chemical change.
3. Background knowledge: The teacher may want to put this in a PowerPoint or on an overhead to review prior to conducting the lesson.
When chemicals combine in new arrangements, they often exchange energy. In this experiment, students discover how dissolving solids in water releases or
absorbs energy.
Dissolving powders and temperature changes: When students add detergent to water, the powders break apart and spread out in the water (in other words, they
dissolve in the water). This causes the temperature of the solution to change.
When it dissolves, each powder molecule detaches from other powder molecules and becomes surrounded by water molecules. This change in arrangement either
absorbs or releases energy. The exchange of energy causes the temperature of the solution to change. When the powder molecules release energy in the solution,
it heats up.
Standard components:
A. Matter can undergo a variety of changes.
B. When matter is changed physically, generally no changes occur in the structure of the atoms or molecules composing the matter.
C. When matter changes chemically, a rearrangement of bonds between the atoms occurs. This results in new substances with new properties.
Misconception Alert: Note that this exchange of energy happens whenever any solid dissolves in water, even table salt. Detergent is used in this experiment because it
produces noticeable changes in temperature with only small amounts of powder. Also note that technically, no chemical reaction is occurring (i.e., the powder doesn't
change into something new, and neither does the water). Instead the molecules are just arranged in a different way, and, in moving to their new arrangement, they
either release or absorb energy.
4. Vocabulary: The teacher will have students make a foldable with five parts using the following vocabulary terms:
Dissolve: when the molecules of a substance separate and become completely surrounded by the molecules of another substance
Exothermic: a process that releases energy, causing it to feel warm; exo- means "out of"
Temperature: a measure of the energy of a substance, based on how fast its molecules are moving
page 2 of 5 Physical change: a process where the substances are not altered chemically. No new products are formed. Chemical bonds are not broken in a physical change. A
physical change can affect the size, shape or color of a substance but does not affect its composition. The substances may be changed to another phase (i.e. gas,
liquid, solid) or separated or combined.
Chemical change: a process where one or more substances are altered into one or more new and different substances
Guided Practice: What activities or exercises will the students complete with teacher guidance?
The "What Effect Does Laundry Detergent have on Water Temperature" activity will be completed by students in groups of three using the attached lab report sheet.
Teacher Role: to circulate around lab to make sure students are:
1. using safety guidelines,
2. following procedures,
3. using equipment to take accurate measurements, and
4. fulfilling roles in collaborative groups.
Teachers can also help guide students if they are struggling with a procedure or question on the lab report.
Student Roles:
1. Recorder: reads the thermometer or LabQuest data, reads the triple beam balance scale mass, records data in chart, and exports data into Excel
2. Equipment Handler: sets up the thermometer or LabQuest and temperature probe, measures the amount of laundry detergent for each cup
3. Leader: adds the detergent and stirs into the water not upsetting the equipment, monitors time and tasks, ensures group is following procedures
Students should follow safety rules in the lab. Teachers should briefly remind students to wear goggles when conducting this lab. The Recorder may remove his/her
goggles to read the measurements and record the data. Students should allow thermometers and temperature probes one minute in the solution (each sample must
be continually stirred) before taking the reading and rinse off thermometers or temperature probes between samples.
Students should complete the lab report. Teachers should post an enlarged copy of the lab report rubric or distribute individual copies so that students will know the
expectations. Teachers will also evaluate the lab reports using the attached answer key.
Independent Practice: What activities or exercises will students complete to reinforce the concepts and skills developed in the
lesson?
1. Students will export the data from their tables in the lab reports to Excel.
If students need background knowledge for making line graph with Excel, they may benefit from the tutorial at About.com.
Once in Excel, students can add trendlines and then click "linear" to see if there is a linear or nonlinear association as well as a positive or negative association.
These graphs should be either saved on a thumbdrive or emailed to the teacher so that he or she can calculate the class average from each group's data.
The teacher can share the class data using the overhead or Smartboard. Students should complete their lab report tables by recording the class averages.
2. Groups should use the GeoGebra tutorial to learn how to export their data and look for outliers, clusters and significance. Students can compare their data to the
class average.
3. Students will read two articles on laundry detergent for the CLEVER model writing assignment. Students can use computers to access the articles online, or the
teacher can distribute hard copies.
"Laundry Problems: It's Not Your Washer's Fault" at About.com
"The Science of Laundry Detergent" at Networx
While reading the articles, students should mark them for facts or other examples to use to support their own claims.
Students will use the CLEVER Model Organizer to organize their thoughts before writing their final draft.
Students should peer review two other students' work and provide feedback using the CLEVER peer review worksheet. In addition, before making their revisions,
students should review the CLEVER model rubric to ensure that everything is included and their work meets expectations.
Closure: How will the teacher assist students in organizing the knowledge gained in the lesson?
Class Discussion: The teacher can put the following questions on the Smartboard or whiteboard. Assign each group one question to discuss and respond to in the
class discussion.
What happened to the laundry detergent when you added them to water? What happened to the water?
The laundry detergent dissolved in the water, and the solution became progressively warmer as the amount of dissolved detergent increased.
If students found they couldn't change the temperature any more, ask them to hypothesize why.
The more powder that dissolves, the more the temperature will change, up to a point. When the water can't dissolve any more powder, adding more powder
won't affect the temperature. It is the process of dissolving that changes the temperature. Note that the solubility of the powder in the water is affected by
temperature. As the water warms up, it can hold more detergent.
What would happen if you did this same experiment again with a different amount of water? Would the temperature change? What about a different amount of
powder?
Increasing the water reduces the temperature change. The same amount of heat is released or absorbed, but there is more water to heat or cool. Differing
amounts of powder also affect the temperature change for similar reasons.
Which amount of laundry detergent released the most energy in the water?
The 25g detergent (the warm solution) released the most energy.
Which chemical is producing the temperature change, the solid or the water? How do you know?
It's the interaction of both water and powder that produces the heat change.
Which chemical changes more when the two are combined?
The powder because it changes state and color; the water also rearranges to accommodate the powder, but it mostly stays the same color and in the same state
(liquid)
Exit Ticket: When heat is released from this complex system, is it the product of a physical change or a chemical change? Justify your answer.
Suggested response: Physical change, because no chemical reaction is occurring (the powder doesn't change into something new, and neither does the water).
Instead, the molecules are just arranged in a different way, and while moving into their new arrangement they either release or absorb energy.
Students can make a case for a chemical change because the laundry detergent has chemicals that release heat when they dissolve in water. Heat is usually an
page 3 of 5 indicator of a chemical change. When chemicals combine in new arrangements, they often exchange energy. In this experiment, we discovered how dissolving the
detergent (solids) in water releases or absorbs energy. Teachers can also use the article "A Study on Chemical Contamination of Water Due to Household Laundry
Detergents" by Geetu Goel and Surinderjit Kaur, 2012, in The Journal of Human Ecology, Volume 38, Number 1, pages 65-69.
Summative Assessment
Students will create charts and graphs showing linear and nonlinear associations using Excel, and export their data into GeoGebra to create graphs showing outliers,
clusters and positive or negative associations.
Students will complete and submit a lab report with their hypotheses, their observations, charts and graphs of their data, and their conclusions. Teachers will evaluate
them with the lab report answer key and the lab report rubric.
Students will use the CLEVER model for writing up how temperature influences chemical changes using their two sets of data and at least one media source. The
teacher will use a rubric to score each of these sections:
CL - This is the first sentence and is the claim made by the student
EVE - Evidence collected from their graphs in Excel and GeoGebra and media sources
R - Reason - Final statement connecting the claim to the evidence collected.
The teacher will distribute the CLEVER model rubric for students to reference when writing up their claims, using evidence to support their claim and explaining their
rationale.
Formative Assessment
Note: This lesson will employ the CLEVER model.
The teacher will use an NSTA safety pamphlet to verify that students are using equipment safely and making accurate measurements in the lab. Inaccurate
measurements or systemic errors can be addressed later by students or the teacher.
Students should use the CLEVER model organizer to write their claim, record their facts, quotes, expertise, data and rationale.
Students should read over two other students' writing using the peer review worksheet to provide peer feedback.
The teacher should circulate to check each lab group's progress.
Students can use the National Partnership for Quality Afterschool Learning checklist for graphs to ensure that they are including all the necessary components in their
work.
Feedback to Students
While circulating around the lab groups, the teacher can give immediate feedback to students on their use of the lab equipment (thermometer or temperature probes)
and assist with any difficulties, including taking accurate readings. Teachers can also make sure students are taking safety precautions and following lab safety rules.
As the teacher shares the Excel chart and graph data from each group versus the class average, students can see how close their set of data compared to the class
average, and see if they had blunders or outliers. If students are struggling with creating graphs, they can be directed to the About.com tutorial on how to make
graphs with Excel.
Students should email their Excel graphs to the teacher or save them to a thumb drive so the teacher can access them. The teacher will be able to use data from each
group to calculate the class average. Teachers can use the to provide additional feedback.
Using the graphs created in GeoGebra, students can identify clusters or outliers and analyze their data to see if it fell within the class average range. Teachers can
provide feedback or ask for clarification from these graphs. If students are struggling with GeoGebra, they can be directed to the GeoGebra tutorial page.
When the students write about their findings using the CLEVER model, they should have at least one other peer read their write-up and provide feedback using the
CLEVER peer review worksheet. Teachers have a section for comments and feedback on the CLEVER model organizer.
After students make their revisions, they should send their write-up to the teacher for feedback. All feedback for this section is provided through a CLEVER model
rubric, which the students will also receive prior to completing their lesson.
ACCOMMODATIONS & RECOMMENDATIONS
Accommodations:
When pairing students for lab groups, be sure to include a medium-high science/math skills students with a special needs student.
Provide calculators if needed.
Students who are unfamiliar with the software may benefit from the tutorials for Excel and GeoGebra as described in the Independent Practice section.
The teacher can allow some students, especially those with special needs, to work on their CLEVER model writing assignment as a small group. The peer review
worksheet can then be used as a feedback tool for the group.
Extensions: An extension for the lab could be to substitute Epsom salt for the laundry detergent. Another alternative would be to substitute Quikcrete concrete mix
(without rocks - make sure to purchase the smooth granular type) in place of laundry detergent so that students can see a chemical change. Students could also
conduct the investigation as written but then allow the water to evaporate, leaving the detergent. Use this powder to repeat the investigation and compare results.
Students can use more articles on laundry detergent for the CLEVER model writing assignment. They should be sure to include the title and URL for each on their
CLEVER model organizer.
Suggested Technology: Document Camera, Computer for Presenter, Computers for Students, Internet Connection, Probes for Data Collection, Basic Calculators, LCD
Projector, Microsoft Office, GeoGebra Free Software
page 4 of 5 Special Materials Needed:
If using LabQuest with temperature probes, make sure the equipment and/or batteries are charged. If using thermometers, the teacher may need to calibrate them
before the students begin the lab.
Make copies of both of the articles so that students have a hard copy mark up as they prepare for their CLEVER model writing assignment.
Make individual student copies, an enlarged copy, or use document camera to display copies of checklists, guidelines and rubrics:
CLEVER model peer review checklist
CLEVER model organizer
Safety guidelines
CLEVER model rubric
Graphs checklist
Have GeoGebra, which is a free software application, installed on the teacher and student computers in advance for easy access as students finish the lab.
Further Recommendations: Make copies of both articles in case of internet failure during the activity.
SOURCE AND ACCESS INFORMATION
Contributed by: Terrie Kielborn
Name of Author/Source: Terrie Kielborn
District/Organization of Contributor(s): Lee
Is this Resource freely Available? Yes
Access Privileges: Public
License: Attribution-NonCommercial 3.0 Unported
Related Standards
Name
SC.8.P.9.3:
LAFS.8.RI.1.1:
MAFS.8.SP.1.1:
Description
Investigate and describe how temperature influences chemical changes.
Cite the textual evidence that most strongly supports an analysis of what the text says explicitly as well as inferences
drawn from the text.
Construct and interpret scatter plots for bivariate measurement data to investigate patterns of association between two
quantities. Describe patterns such as clustering, outliers, positive or negative association, linear association, and
nonlinear association.
page 5 of 5