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The Arizona STEM Acceleration Project

A Rainbow Around Me: A Unit on Plant Chromatography Lesson 1

Even Better Than the Real Thing? Synthetic Pigments in Art

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Even Better Than the Real Thing?

Synthetic Pigments in Art

An 8th Grade STEM Lesson

Jaime Camero

11/28/2023

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Notes for Teachers

Prior to teaching this unit, the students should have engaged in lesson focused on biodiversity and the role of pollinators in the sustaining of life
This project can get quite messy and the colors will stain. Be sure students wear gloves and safety goggles.
Review your lab procedures before doing any of the three lessons in the unit.
This is an introductory lesson, but doesn’t need to be done prior to completing the plant chromatography lesson if you don’t have time to do all three lessons.

List of Materials

For the Class:

Video
Book: The Day the Crayons Quit or The Day the Crayons Quit (read aloud)

For Each Group:

1 coffee filter or filter paper
isopropyl alcohol
scissors
2 popsicle sticks
2 clear plastic cups
black and colored permanent markers
tape
ruler

For Each Student:

Notebook and pencil

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Arizona Science Standards

8.P1U1.2 Obtain and evaluate information regarding how scientists identify substances based on unique physical and chemical properties.

Arizona Science & Engineering Practices

ask questions
plan and carry out investigations
analyze and interpret data
construct explanations
engage in argument from evidence
obtain, evaluate, and communicate information

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Arizona ELA Standards

8.RL.3

Analyze how particular lines of dialogue or incidents in a story or drama propel the action, reveal aspects of a character, or provoke a decision.

8.RL.6

Analyze how differences in the points of view of the characters and the audience or reader (e.g., created through the use of dramatic irony) create such effects as suspense or humor.

8.W.3

Write narratives to develop real or imagined experiences or events using effective technique, relevant descriptive details, and well‐structured event sequences.

8.W.7

Conduct short research projects to answer a question (including a self‐generated question), drawing on several sources and generating additional related, focused questions that allow for multiple avenues of exploration.

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Arizona Technology Standards

Standard 3. Knowledge Constructor - Students critically curate a variety of resources using digital tools to construct knowledge, produce creative artifacts, and make meaningful learning experiences for themselves and others.

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Objectives:

After watching a video, reading a book, and participating in a hands-on lab, all learners will be able to demonstrate understanding of practical applications of chromatography and how colors may be separated out based on chemical properties of the solvent.

Learning Outcomes:

Plan and carry out investigations
Analyze and interpret data
Define chromatography
Differentiate between natural pigments and synthetics
Understand the use of solvents in developing synthetic pigments

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Agenda (50-60 minutes)

Anchoring Phenomenon
Research
Watch the video
Read the book
Complete the lab
Create a crayon “profile,” write a letter, or create a work of art
Generate a list of “wonderings”

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Intro/Driving Question/Opening

Intro:

Iceberg Model of Systems Thinking

Driving Questions:

What do you notice? What do you wonder?

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Research

What is pigment?
What were early pigments made from?
How did the invention of synthetic pigments come about?
What were some of the most popular pigments?
Why was there a need for synthetic pigments?
What is chromatography?
What are some practical applications of chromatography?

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Read Aloud

Iceberg Model or See/Think/Wonder

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Hands-on Activity Instructions

Cut your coffee filters into half inch-wide strips, making sure the ends are square (not rounded).
Take a black marker and draw a line across one strip of coffee filter half an inch from one end. (Note: The line placement needs to be fairly precise)
Tape the strip to a popsicle stick so that the end with the marker line hangs down from the stick and the bottom of the filter strip just barely rests on the bottom of the cup (see the image).
Ask me to pour your isopropyl alcohol into your cups, ensuring the marker line is above the top of the liquid.
Watch as the liquid moves up the filter and pulls the colored inks out of the ink line.
Write a description of the colors they found in your black ink in your notebook and draw a picture of what happened on your iceberg model (6).
Experiment with colored markers and also with water rather than alcohol to see if you obtain different results. Write a description of your results in your notebook and draw a picture of what happened on your iceberg model (6).
Record your experimental process in your iceberg model (7).
Compare results and be ready to discuss your experiment outcomes.

Photo:TeachEngineering.org

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~20 minutes

Hands-On Activity:

Divide students into groups of two or three and hand out all of the supplies except for the isopropyl alcohol.
Explain to students that they will use the alcohol (a solvent) to separate the colors into various marker inks.
Watch this video to familiarize yourself with the process.
Remove the iceberg model image and instructions if not using and have students keep a record in their notebooks.
Discuss: Were you surprised by any of the colors you found in the inks? Why do you think the isopropyl alcohol separated the inks better than the water? (When you dip a portion of the chromatography paper into the solvent, the solvent begins to move up the paper. As the solvent rises up the paper, it dissolves the ink on the paper into its components. The ink components travel up the paper with the solvent, and the distance they travel is based on how readily each component dissolves in the solvent.)

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Assessment

Science: Explain the principle behind chromatography and how it is used to separate components in a mixture. Provide a detailed description of the factors that can affect the separation process and discuss how these factors can be manipulated to achieve better results (water vs. isopropyl alcohol). Finally, propose a real-world scenario where chromatography could be applied for analysis.
ELA: Choose a crayon from the story and create a “profile” for that crayon based on its chromablend. Using the the chroma profile, tell a story to describe its personality characteristics.

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Differentiation

Use only one solvent
Limit the colors that students may use to 2-3
Pre-cut the filter papers
Provide a word bank for the science assessment and a paragraph frame for the ELA assessment

Remediation

Extension/Enrichment

Try the experiment with other solvents.
Have the students use their phones to take photos of their strips and load the pictures into one of the apps from the “notes” slide to identify the exact colors found in their strips.
Explore the chromatography for water pollutant identification lab/lesson.
Encourage students to research real-world applications of chromatography in various fields, such as forensics, biology, or chemistry. Have them present their findings through a short presentation or poster.