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Daily Do

How can we pull colors apart?

Crosscutting Concepts General Science Is Lesson Plan NGSS Physical Science Science and Engineering Practices Early Childhood Informal Education Preschool

Sensemaking Checklist

Welcome to NSTA's Daily Do

Teachers and families across the country are facing a new reality of providing opportunities for students to do science through distance and home learning. The Daily Do is one of the ways NSTA is supporting teachers and families with this endeavor. Each weekday, NSTA will share a sensemaking task teachers and families can use to engage their students in authentic, relevant science learning. We encourage families to make time for family science learning (science is a social process!) and are dedicated to helping students and their families find balance between learning science and the day-to-day responsibilities they have to stay healthy and safe.

Interested in learning about other ways NSTA is supporting teachers and families? Visit the NSTA homepage.

What is sensemaking?

Sensemaking is actively trying to figure out how the world works (science) or how to design solutions to problems (engineering). Students do science and engineering through the science and engineering practices. Engaging in these practices necessitates students be part of a learning community to be able to share ideas, evaluate competing ideas, give and receive critique, and reach consensus. Whether this community of learners is made up of classmates or family members, students and adults build and refine science and engineering knowledge together.


In today's Daily Do, How can we pull the colors apart?, students use the patterns they identified mixing colors in the What happens when we mix colors? Daily Do to predict what colors they will see when colors are "pulled apart". This Daily Do is intended for young children and their families.

*This task would be better named, What happens when we unmix colors? The title was chosen to avoid confusion with the first lesson in this series.


Watch the video Learn Color Mixing with Chromatography to learn how to do chromatography with your young students.


  • poster with color mixing patterns students identified in What happens when we mix colors?
  • white coffee filters
  • purple, green, orange and black water-based markers
  • pencils (in place of the wooden skewer shown in the video)
  • cellophane tape
  • clear plastic cups (you can use cups for chromatography and to distribute water)
  • water
  • paper towel
  • scissors
  • ruler
  • plain white paper

Make Coffee Filter Strips

  1. Cut the coffee filters into about 1-inch wide strips.
  2. Measure the height of the cups to determine how long the strips should be. Cut the strips to match the cup height. (It's OK if the strips are slightly shorter than the cup height.)
  3. Cut at least four coffee filter strips for each student.
  4. With a pencil, draw a line across each strip about 1/2 inch from the bottom. (Students can trace the lines with their markers.)

The goal of this lesson is for students to use the patterns they identified when they mixed red, yellow and blue crayons/markers in the What happens when we mix colors? Daily Do to predict which colors they will see when black, purple, green and orange are "pulled apart". How much of the remaining set-up you choose to let your students do depends on additional goals you have for your students and the time available.


Refer students to the class poster with the patterns they identified in mixing colors (mixing yellow and blue make green; mixing blue and red make purple; etc.). Point to green on the poster and ask, "What two colors make green when mixed together?" Students will likely say yellow and blue, but accept all answers. Follow up after each share by asking, "Why do you say so?" Ask them, "If we could unmix green - pull the colors that make green apart - what colors would we see?" Tell students to turn to a partner and share their ideas. Then, ask students to share their ideas with the class. Record all ideas; you might draw all of the color combinations (predictions) students share beneath the color green on the poster.

Note: If students don't know their colors, you might give them red, yellow, and blue paper squares to use to communicate their ideas.

Say to students, "Let's unmix the green (pull the colors that make green apart) and find out!"

Give each student (or pair of students) the following materials:

  • one strip of filter paper
  • green marker
  • empty plastic cup
  • pencil
  • piece of tape
  • water (very small amount)
  • paper towel
  • sheet of plain paper

Ask students to trace the pencil line on the filter paper strip with the marker. It's OK if they don't trace the line exactly. Next, show students how to tape the filter paper to the pencil. Then ask students to pour water into their cup. (You might mark all the cups about 1/4 inch from the bottom before handing them out and ask students to fill the cup to the line. Another option is to pour the water into the plastic cups before handing them out.) Finally, show students how to hang the strip in the cup. As you move around the room, ask students to describe what they are observing. Encourage them to continue sharing with each other before you move on to the next table.

When you notice the colors have separated to the extent you observed in the video, ask students to remove the pencil and filter paper from the cup. Help them take the filter paper strip off the pencil and lay it on the white paper to dry. Ask, "What colors do we see when we unmix green?" Students will likely say blue and yellow. Circle that color combination on the poster.

Ask students, "Which two colors mix to make green? (Point to the colors on the poster as students share them.) Which colors do we get when we unmix green? (Again, point to the colors on the poster.) What do you notice?"

Next, show students the orange marker. Ask them, "What colors do you think we'll see if we unmix orange?" Tell students to share their ideas with their partner. As you move around the room, listen for students to share the idea that the two colors you mix to get a new color are the same colors you get when you unmix that color. When you bring the class back together, call on students who shared this idea first. Then ask if anyone has a different idea. Make sure to ask after each student shares, "Why do you think so?" Record all color combinations students share (predictions) on the poster.

Give students a new coffee filter strip, orange marker and piece of tape. If the water in the cup is still clear, students can use it again. Otherwise, give students a clean or well-rinsed cup to place the orange strip in. Follow the same procedure you did with the green marker.

After students remove the orange strip and lay it on the white paper to dry, ask them, "Which two colors mix to make orange? (Point to the colors on the poster as students share them.) Which colors do we get when we unmix orange? (Again, point to colors.) What do you notice?" Students will likely articulate the same colors that mix to make a new color are the same colors you see when you unmix that new color.

Continue the investigation following the same procedure for the purple and black markers. When separating the purple ink, you might have to point out the blue ink that accumulates near the top of the strip to students.

Ask students, "How can we use this pattern (point to poster) to answer our question, What happens when we unmix colors?"

Chromatography strips

Art Extension


  • paper strips from chromatography investigation
  • construction paper, water color paper, and/or plain paper
  • scissors
  • glue or tape
  • markers, variety of colors

Arrange the materials on students' tables and encourage students to experiment making a picture. Some students might create specific pictures or designs. Others might begin by placing things on the paper and then building out, creating designs as they go and modifying their ideas with what is taking shape on the page.

NSTA Collection of Resources for Today's Daily Do

NSTA has created a How can we pull colors apart? collection of resources to support teachers and families using this task. If you're an NSTA member, you can add this collection to your library by clicking Add to my library near the top of the page.

Check Out Previous Daily Dos from NSTA

The NSTA Daily Do is an open educational resource (OER) and can be used by educators and families providing students distance and home science learning. Access the entire collection of NSTA Daily Dos.


The art extension is inspired by the post "Preschool Mural Ideas for Spring" on the Pre-K Pages website.

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