Objective
By the end of this lesson, you will understand how rainbows appear and the science behind them.
Materials and Prep
- Water spray bottle
- White paper or white wall
- Flashlight
- Clear glass of water
No prior knowledge is required for this lesson.
Activities
- Activity 1: Create a Rainbow
- Activity 2: Water and Light
Fill the water spray bottle and mist the air to create tiny water droplets. Shine the flashlight towards the mist and observe the rainbow that appears. Experiment with different angles and distances to see how the rainbow changes.
Fill the clear glass with water and place it on a table near a window. Position yourself so that you can see the glass and the window. Observe how light passes through the glass and refracts, creating a rainbow-like effect on the surface or nearby objects.
Talking Points
- Light and Refraction
- Dispersion of Light
- Reflection and Refraction
- Primary and Secondary Rainbows
- Angle of Sunlight
"When light passes through water droplets in the air, it bends or refracts. This bending of light is called refraction. It happens because light travels at different speeds through different mediums, like air and water."
"When light enters a water droplet, it gets dispersed or split into its different colors. This is because different colors of light have different wavelengths, and they bend at slightly different angles."
"When light exits the water droplet, it reflects off the inner surface and undergoes another refraction. This causes the light to change direction and form a circular arc, which we see as a rainbow."
"Sometimes, you might see two rainbows. The primary rainbow is brighter and has red on the outer edge, while the secondary rainbow is fainter and has red on the inner edge."
"The angle of the sunlight and your position relative to the water droplets determine the size and shape of the rainbow. That's why rainbows are often seen after rain showers when the sun is low in the sky."