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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 that 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 patterns they observed and recorded in What happens when we mix colors? to predict what colors water-based marker inks are made from. While this activity could be completed on its own, with students excitedly making noticings about the marker inks as they separate into their component colors, teaching these lessons together supports students in building understanding of patterns (see below).
How can we pull colors apart? is part of an instructional sequence in which students coherently build the idea that patterns can be used to describe the phenomenon of mixing colors together produces new colors and make predictions about what happens when you mix those colors again and about the colors that emerge when you pull the new colors apart.
Watch the video Learn Color Mixing With Chromatography to learn how to do chromatography with your young students.
Make Coffee Filter Strips
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 setup 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 sharing 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:
Ask students to trace the pencil line on the filter paper strip with the marker. It's okay 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 their noticings with one another.
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 place 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 in which to place the orange strip. Follow the same procedure you did with the green marker.
After students remove the orange strip and place 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 to students the blue ink that accumulates near the top of the strip.
Ask students, "How can we use this pattern (point to poster) to answer our question, What happens when we unmix 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 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, located near the top of the page.