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http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/rbowpri.htmlThe Sumerian hero Gilgamesh traveled the world in search of a way to cheat death. On one of his journeys, he came across an old man, Utnapishtim, who told Gilgamesh a story from centuries past. The gods brought a flood that swallowed the earth.

Gilgamesh Rainbow Magic Dawkins

The Magic of Reality: How We Know What’s Really True [Richard Dawkins]

The gods were angry at mankind so they sent a flood to destroy mankind. The god Ea, warned Utnapishtim and instructed him to build an enormous boat to save himself, his family, and “the seed of all living things.” He does so, and the gods brought rain which caused the water to rise for many days.

When the rains subsided, the boat landed on a mountain, and Utnapishtim set loose first a dove, then a swallow, and finally a raven, which found land. The god Ishtar, created the rainbow and placed it in the sky, as a reminder to the gods and a pledge to mankind that there would be no more floods.  A similar story, with theological modifications, is in the Hebrew Bible as the story of Noah and the Ark.

This story comes from the Epic of Gilgamesh

In physics we learn that rainbows are produced by electromagnetic radiation – visible light – reflecting in marvelous ways from the dispersion of light.

Let’s start with the basics:

A prism separates white light into many colors

How? Each wavelength of light refracts by a different amount

The result is dispersion – each wavelength is bent by a different amount



The physics of rainbow formation

Rainbows: At Atmospheric optics



Rebecca McDowell  How rainbows form


Do rainbows have reflections?

It certainly seems like rainbows can have reflections. Consider this great photo by Terje O. Nordvik, September ’04 near Sandessjøen, Norway.

But rainbows aren’t real objects – and so they literally can’t have reflections!
So what are we seeing here? See Rainbow reflections: Rainbows are not Vampires


Learning Standards

2016 Massachusetts Science and Technology/Engineering Curriculum Framework

HS-PS4-3. Evaluate the claims, evidence, and reasoning behind the idea that electromagnetic radiation can be described by either a wave model or a particle model, and that for some situations involving resonance, interference, diffraction, refraction, or the photoelectric effect, one model is more useful than the other.

SAT subject test in Physics: Waves and optics

• General wave properties, such as wave speed, frequency, wavelength, superposition, standing wave diffraction, and Doppler effect
• Reflection and refraction, such as Snell’s law and changes in wavelength and speed
• Ray optics, such as image formation using pinholes, mirrors, and lenses
• Physical optics, such as single-slit diffraction, double-slit interference, polarization, and color.


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