Simple Rainbow Science Experiment for Kids
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Spring is here and you and your students will love this Simple Rainbow Science Experiment for Kids that is quick and fun to do! This would be a great experiment to try around St. Patrick’s Day or perhaps while studying a weather unit. Students may want to draw or color their rainbows in a science notebook as well. We love doing science experiments in my classroom and this easy rainbow experiment proves that they don’t have to be complicated or hard to prep for!
*Pair with our St. Patrick’s Day Centers and Activities for Pre-K & Kindergarten!

Simple Rainbow Science Experiment for Kids
Bring some hands-on science fun to your classroom with this easy, no-mess experiment! You can do this science experiment in the springtime or any time of the year!
Teach your early learners all about reflection, refraction, and dispersion of light!
To make your own rainbow, you will need:
- a glass of water
- a sunny window
- a sheet of white paper
How to Make a Rainbow
To begin, invite your child to place a glass of water near a sunny window. For best results, look for a direct beam of sunlight. When the sun is low in the sky (early or later in the day) works best.
Next, place a sheet of paper on the other side of the glass. You should notice a rainbow that is projected onto the sheet of paper!

RELATED RESOURCE: Easy Readers – Color Words Collection
Here’s How It Works!
Sunlight is made up of various wavelengths, and each wavelength appears as a different color. The water is used to reflect and refract light. As the sunlight passes through the water, the sunlight is separated into a spectrum of colors forming a rainbow.

Questions to Consider:
- Can you think of another way to make your own rainbow?
- What happens if you change the shape or size of the glass of water?
- What happens if you place the paper further away from the glass?
- Add a few drops of food coloring to the water. Are you still able to make a rainbow?
- Replace the water with mineral oil. What happens?
- If there were no signs of rain, would you be able to see a rainbow outside? Why or why not?
- Draw and color your observations in a notebook.
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So simple but so amazing. Thank you!