Catching Rainbows

Children will investigate rainbows.


Lesson Objective

Children will investigate how rainbows appear, their colors, and make a rainbow in the classroom.


What You'll Need

  • Medium-sized clear glass jars – 1 per child
  • Water – enough to fill each jar
  • Windowsill
  • Bright sunlight
  • Large sheet of white butcher paper
  • Rainbow-colored watercolor paints, markers, or crayons – 1 set per 2 children

What To Do

Note: Try to plan this activity for a bright, sunny day.

  • Discuss rainbows with the children (see Guiding Student Inquiry).
  • Tell the children they are going to make a rainbow in the classroom with water and light.
  • Fill the jars with water to the top.
  • Set the jars on the windowsill in bright sunlight. (Note: The jars should stick out over the edge just a little bit.)
  • Place the white butcher paper on the floor in front of the window—use a large piece of paper to allow more space for the children to work.
  • A rainbow will be “captured” (projected) onto the paper. This will depend on how bright the Sun is shining through the window and the position of the glass jar. You may have to move the jar from side to side on the windowsill until you see the rainbow reflected on the paper.
  • Discuss what is happening (see Did You Know?), and have the children name the colors of the rainbow: red, orange, yellow, green, blue, indigo, violet.
  • Explain that sunlight contains all of these colors mixed together, but when the sunlight hits water, all of the colors are separated, creating a rainbow. Continue by explaining that the colors in the rainbow always appear in the same order.
  • Allow the children to paint the colors directly onto the paper on the floor as the rainbow is reflected there.

Guiding Student Inquiry

  • Tell me where you have seen a rainbow.
  • Describe what was happening outside when you saw the rainbow.
  • Explain how you think rainbows appear in the sky.
  • Tell me the colors of the rainbow.
  • Explain why a rainbow in the sky is curved.
  • Describe what is happening to create the rainbow on the floor.

Explore, Extend & Integrate

  • Place prisms in the science area for the children to investigate, and then search for rainbows created by the prisms in sunlight.
  • Place paper and rainbow-colored paints, crayons, and markers in the art center, so they are available for further investigation.

Check for Children’s Understanding

  • Was each child able to see the rainbow on the paper?
  • Could the children describe how a rainbow is made?
  • Was each child able to color or paint part of the rainbow?
  • Could children name the colors in the rainbow?


Did You Know?

A rainbow is a curved arc of light of many colors across the sky. Rainbows occur after a storm, when the Sun begins to shine while the air is still filled with raindrops. Rainbows are caused by the sunlight bending as it shines through drops of water. The raindrops act like miniature prisms and bend the different colors that are found in sunlight. The light spreads out into an arc-shaped band of colors that are reflected back to us, and we see that band of colors as a rainbow.

Sunlight looks white, but it actually contains many colors mixed together. When sunshine hits water or raindrops, all of the colors get separated. A rainbow is actually a full circle of light, but because we are looking at it from the ground, we can only see an arc of the rainbow. The lower the Sun is in the sky, the higher the arc of the rainbow will be. Sometimes, we can see a double rainbow. The inner rainbow is brighter and has a red band on the top and a blue band on the bottom; in the outer rainbow, the colors are reversed!

Vocabulary: Child-Friendly Definitions

  • water – a clear liquid. We drink water that comes out of our faucets, and rain is water.
  • rainbow – a curved arc of light of many colors across the sky.
  • color – light as our eyes see it; red, blue, and yellow are some colors.
  • sunlight – light of the Sun; sunshine.
  • reflect – to throw back an image of, like a mirror.
  • violet – a shade of purple; the last color in the color spectrum.

Lesson Tips

  • Make sure jars are clear and clean to get the best reflection from the sunlight.
  • To help create the rainbow, place a mirror or CD into water in the jar.


  • Chasing Rainbows by Tish Rabe
  • Elmer and the Rainbow by David McKee
  • What Makes a Rainbow? by Betty Ann Schwartz
  • A Rainbow of My Own by Don Freeman

Home School Resources

Home educators: use these printable lesson PDFs to teach this lesson to your home schoolers. They're available in English and Spanish.

Home/School Connections

Las Conexiones a la Casa

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Content Provided By

Common Core State Standards Initiative – These lessons are aligned with the Common Core State Standards ("CCSS"). The CCSS provide a consistent, clear understanding of the concepts and skills children are expected to learn and guide teachers to provide their students with opportunities to gain these important skills and foundational knowledge [1]. Visit the CCSS