First Grade · Science · week 15

Rainbow hunt with sunlight

Discover that sunlight is made of many colors by splitting it into a rainbow with a CD or prism.

Sunlight looks white or yellow, but it is secretly made of every color of the rainbow, mixed together. You can prove this by splitting sunlight apart using something like a prism or the shiny back of a CD.

When sunlight hits a CD or prism at the right angle, it bends and separates into its hidden colors: red, orange, yellow, green, blue, and purple, in that order.

📋 For the teacher
Teach it (10–15 min):
  • Do this on a bright sunny day for the clearest rainbow; a cloudy day may not work well.
  • Let your child hunt for the right angle themselves rather than holding the CD for them -- the hunting is part of the fun.
  • If you have a real prism, try it too and compare its rainbow to the CD's rainbow.
  • Talk about real rainbows in the sky after rain as the same idea: sunlight splitting into its hidden colors, this time by raindrops instead of a CD.
Talk about it:
  • What colors did you find in your rainbow hunt?
  • What does the rainbow tell you about sunlight?
  • How is a CD rainbow like a rainbow in the sky after it rains?

Mastery looks like: They produce a rainbow from sunlight using a CD or prism and explain that it shows sunlight is made of many hidden colors.

Common stumbles: Giving up if the first angle does not work, instead of continuing to hunt; thinking the CD makes colors rather than splits light that was already there.

Homework for this lessonType it, write it with a stylus, or print it for pencil & paper.open →
Records attendance + 15 min of Science for this learner.
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