Atmospheric Optics and Rainbows

Atmospheric Optics and Rainbows

Refraction

• Refraction is the bending of light as it passes through a medium with a different optical density
• In the atmosphere, light is refracted, or bent, as it passes from air into water droplets

Dispersion

• Dispersion is the spreading of light into its individual colors, also known as chromatic dispersion
• This occurs when light passes through a prism or, in the case of rainbows, water droplets in the air
• Dispersion is responsible for the color separation in a rainbow

Total Internal Reflection

• Total internal reflection occurs when light hits the back of a water droplet at an angle greater than the critical angle
• The light is then reflected back into the droplet and exits the droplet at the same angle it entered, creating the bright colors of the rainbow

Angle of Refraction

• The angle of refraction is approximately 42° for red light and 40° for violet light
• This is why the colors of the rainbow always appear in the same order: red, orange, yellow, green, blue, indigo, and violet

Optimal Viewing Conditions

• Rainbows are typically visible when the sun is behind the observer and the air is filled with water droplets at an angle of around 42°
• The optimal viewing time is usually during the late morning or early afternoon when the sun is high in the sky

Atmospheric Optics and Rainbows

Refraction

• Light bends as it passes through a medium with a different optical density, such as from air into water droplets in the atmosphere.

Dispersion

• Chromatic dispersion occurs when light passes through a prism or water droplets, spreading it into its individual colors.
• Dispersion is responsible for the color separation in a rainbow, creating a band of colors.

Total Internal Reflection

• When light hits the back of a water droplet at an angle greater than the critical angle, it undergoes total internal reflection.
• The reflected light exits the droplet at the same angle it entered, producing the bright colors of the rainbow.

Angle of Refraction

• The angle of refraction varies with wavelength, with red light being refracted at approximately 42° and violet light at 40°.
• This consistent refraction pattern is why the colors of the rainbow always appear in the same order: red, orange, yellow, green, blue, indigo, and violet.

Optimal Viewing Conditions

• Rainbows are typically visible when the sun is behind the observer and the air is filled with water droplets at an angle of around 42°.
• The optimal viewing time is usually during the late morning or early afternoon when the sun is high in the sky.

Understand the principles of refraction and dispersion in the atmosphere, explaining how rainbows are formed. Learn about the bending of light and the spreading of light into its individual colors.