What makes a rainbow?

Answer 1

Rainbows are created by sunlight striking billions of tiny droplets of water in the atmosphere, usually after a rain, but any source of fine water spray can create a rainbow.

Rainbows are caused by the reflection and refraction of sunlight through water droplets in the atmosphere. The water droplets act as individual refractors and reflectors that "split" (refract) the light into the respective colors of the rainbow. The refracted light is reflected off the back surface of the individual rain drops and to the observer.

The physics of the process is the same as the physics behind a prism, i.e. refraction breaks up white light into colors as it passes through a prism. With water droplets, refraction occurs but it is complicated because the droplets are spheres and the light has to reflect from the droplet as well. Nonetheless, the rainbow after a rain is a result based on the principle of a prism.
A rainbow is formed when sunlight passes through a light rainstorm.
The conditions for seeing a rainbow are that the sun be shining in one part of the sky, and that water droplets in a cloud or in falling rain be on the other side. To view a rainbow you need to be at a 42 degree angle. Light is dissipated by the water drops which act as small prisms, the colors refract into the air particles.
When the sun's rays refract light through millions of raindrop's color apears on the horizon, known as a rainbow.
A very good question. Rainbows, simply put, are the end result of white light being factured into several colors. "Now how does this work?" you ask. Well, let's go back and figure out what white light is. According to science, the colors we see are merely reflections of certain wavelengths of light. Every object absorbs light, taking in all of its color. The color that isn't absorbed is what is reflected into our eyes, thus giving the appearance we see. White is a unique color. Contrary to what it looks like, the color white is actually the sum of all colors combined. So, what does this have to do with a rainbow? Have you heard of a prism? Prisms are transparent objects with flat surfaces and refract light. They're often made of glass and can be found in science classes or little fun shops. What happens with a prism is that the white light shining into it is broken up into individual wavelengths of light. The end result: a rainbow. Now, let's go back to the rainbows we see in the sky. They work the same way, only with water. We often times see rainbows at the end of a rain because the rain clouds move away, allowing light to shine down. This light shines through the light mist that is left behind or moving away with the clouds, producing a prism effect. Cool, huh? Did you know that Pink Floyd used a prism on a widely known album cover? ~Apple Juice
Rainbows are caused by the reflection and refraction of sunlight in millions of raindrops.

The Sun must be behind the observer and fairly low for a rainbow to occur. This is why they're seldom seen in the middle of the day. Sometimes, if the light has been reflected twice inside each raindrop, a second fainter rainbow can be seen about 9 degrees outside the first. The colors on the outside one are reversed in order, red being in the inside. A third rainbow is occasionally seen and fourth rainbow is almost on top of the first so it is often not recognized.

A rainbow is actually a spectacular natural optical phenomenon. Individual raindrops act like tiny prisms, splitting the white light from the Sun (or other white light source) into a continuum of different hues, from deep violet to deep red. From any given point BETWEEN the Sun and the rain droplets, a single droplet would appear to refract a tiny speck of light in one particular hue, depending on its position. However, billions of raindrops combine their refractions to form the whole image, a circular arc containing a complete range of colors.

If one were to draw a straight line from the Sun to the Observer, then project that line straight along, it ALWAYS points to the very center of the arc formed by the rainbow. (Since the ground usually interferes with a complete image, one almost always sees just an arc. At higher altitudes, however, the arc continues farther around to form a circle.)

The colors of the primary rainbow are always the same - starting from the outside: red, orange, yellow, green, blue, indigo, violet.

The reason that it is IMPOSSIBLE to "approach" one end of the rainbow is that the rainbow phenomenon simply recedes as the viewer travels toward it. If you use a garden hose to spray fine droplets you can see the entire circle of "rainbow" just a few feet away. A it is a circle there is no "end" to the rainbow.

When the sun is out (and preferably low near the horizon) and it is raining a rainbow occurs as the rays of the sun refract in and reflect from raindrops. Look away from the Sun when it is raining in that direction - away from the Sun - and you can often see 1, 2 or rarely even more rainbows centered around the "anti-solar point" (the shadow of your head).