Rainbows happen after a passing rain shower. This is because a rainbow will only form when light passes through a water droplet. You can read more about rainbows here.

The conditions were just right on May 3rd. Many 2 News viewers were able to Report!t. A double rainbow was spotted. Sometimes there is a second reflection in the water droplet where the light is re-reflected. The angle is slightly different and a second rainbow can be seen above the primary rainbow. The colors are reversed.

Color travels as different sized wavelengths. As the light travels through the water droplet it bends at different angles. Violet is the shortest wavelength and red is the longest wavelength. The water droplet helps separate the different wavelengths so you can see all of the colors.

In a similar way, different wavelengths are reflected to produce different colors. The sky appears blue because the shorter wavelengths reflect and scatter off the particles in the atmosphere. Blue is a shorter wavelength. This is known as Rayleigh Scattering.

QUESTION: How does a rainbow form?

HYPOTHESIS: If we get the sun to travel through water at the perfect angle, then a rainbow will form.

MATERIALS: Clear glass or jar, water, a white piece of paper or light colored sidewalk.


Fill the glass with water so that it is at least half full.

Walk outside and find a light colored surface or bring a white piece of paper.

Make sure the sun is shining and you are not in a shadow.

Hold the class out near the surface and adjust the angle until you see a rainbow on the ground.

OBSERVATION: You should be able to see all the colors of the colors of the rainbow.

Unless you have a circular object you will not see the bow or circular shape.

CONCLUSION: As the light traveled through the water or even the glass, it was bent, separating the light into different wavelengths.

You can also use a glass prism if you happen to have one of those at home.