Rainbow Experiments · Science Preschool Lesson Plan Activities Activities

This are two simple experiments to simulate how a rainbow is caused.

What is a rainbow? A rainbow is a curved arc of light of many colors across the sky. Rainbows are caused by the sun's shining through drops of water during or after a rain.

Incorporate these with any activity or holiday with a rainbow theme.

Rainbow Experiment 1: Catching a Rainbow Indoors

Materials: clear glass or medium sized clear jar filled with water to the top, window sill, bright sunlight, white paper, watercolor paints or crayons.


1. Fill a glass or clear jar with water to the top.

2. Set glass/jar on window sill in bright sunlight.

3. Glass or jar should stick out over the ledge just a little bit.

4. Place a white piece of paper on the floor in front of the window (tape 2 or 3 pieces to form a poster size and obtain a bigger rainbow image).

5. A rainbow will be captured/reflected on the paper. This will greatly depend on how bright the sunlight is and the positioning of the glass jar, so move the jar side to side on the window sill to help the process until you see the rainbow reflected on the paper.

6. Quickly draw lines to capture the rainbow and children can paint directly on the paper in the floor as the rainbow is reflected there.

For an experiment for older children (6+) you may want to try Kidzone's Catch a Rainbow Experiment

Rainbow Experiment 2: Catch a Rainbow with a Garden Hose
The sun must be shining, with your back to the sun. Have child hold the hose and help child make a fine mist and find the rainbow! (usually the hose will have a hose mister that can be adjusted to achieve a fine mist)