Ka ʻōʻili ʻana
(Formation)
Pehea e ʻōʻili ai ke ānuenue?
I ʻōʻili ke ānuenue, pono i ʻekolu mea ma loko o ke aouli. ʻO kēia mau mea:
1. Pono ka lā e noho ma kekahi huina pololei.
2. Pono ka lā e noho ma hope o ka mea nānā.
3. Pono ka nui pololei o ka huna wai ma loko o ke aouli.
Luaʻehu ke ānuenue ma Hawaiʻi nei, no ka mea, nui ʻino ka lā a me ka huna wai i loko o ke aouli.
Ma muli o ke aka ʻana a me ke kīkeʻe ʻana o ko ka lā kukuna ma loko o ka huna wai i ka lewa e ʻōʻili aʻe ai ke ānuenue. No laila, i ʻike kākou i ke ānuenue, aia kekahi mau huna wai e pūailewa. ʻO ia hoʻi, ka huna wai ma loko o ke ao, ka uhiwai, a iʻole ka noe. E nānā ʻia ke kiʻi o lalo iho nei. I ka manawa o ke kukuna lā e komo ai i kekahi huna wai, kīkeʻe ʻia i ka paʻapū o ka wai. ʻO ia hoʻi, ʻOi aku ka paʻapū o ka wai ma mua o ko ka ea paʻapū. ʻO ka makemakika o kēia hopena ke kānāwai a Snell. Ma muli o ke kīkeʻe ʻia ʻana i ka huna wai, kaʻawale ke ao keʻokeʻo i ke ao waihoʻoluʻu he ʻehiku. Ma ka hope o ka huna wai e hoʻoaka iho ai kēla me kēia ao waihoʻoluʻu. Kīkeʻe hou ʻia ia ao waihoʻoluʻu i ka haʻalele ʻana i ka huna wai.
Eia nā waihoʻoluʻu o ke ānuenue: ʻulaʻula pua rose, ʻōlenalena ʻalani, lenalena maoli, ʻōmaʻomaʻo, uliuli, ʻinikō, mākuʻe (waioleka). Aia ka ʻulaʻula ma ka luna o ke ānuenue a waioleka ma ka lalo. Inā ʻoe nānā pono i ia kiʻi, haʻalele ka waihoʻoluʻu ʻulaʻula iā ka huna wai i lalo a me ka waioleka i luna, akā naʻe, aia ka ʻulaʻula ma luna a me ka waioleka ma lalo o ke ānuenue ke ʻike aku. No ke aha kēia loli ʻana i ke kūlana o nā waihoʻoluʻu?
ʻO ke anahonua ka hāʻina. ʻŌʻili nō ka wēkiu o ke ānuenue ma ka huina kanahākūmālua a i ka mea nānā a ʻoiai, ʻoi aku ke kīkeʻe ʻana o ka waihoʻoluʻu waioleka ma mua o ko ka waihoʻoluʻu ʻulaʻula, ʻike wale nō kākou i ka waihoʻoluʻu ʻulaʻula mai nā huna wai ma ka wēkiu o ke ānuenue. Hala nā waihoʻoluʻu ʻē aʻe ma luna o ka maka o mea nānā. ʻŌʻili ke kumu o ke ānuenue ma ka huina kanahā. ʻOiai, emi ke kīkeʻe ʻana o ka waihoʻoluʻu ʻulaʻula, ʻike wale nō kākou i ka waihoʻoluʻu waioleka mai nā huna wai ma ke kumu o ke ānuenue. Hala nā waihoʻoluʻu ʻē aʻe ma lalo o ka maka o ka mea nānā. Hiki ke ʻike ʻia kēia hopena ma loko o ke kiʻi o lalo iho nei. Ma muli o ka neʻe ʻana o ka lā a me ka huina kanahākūmālua a i ka mea nānā ma nā manawa a pau loa, loli kahi kiʻekiʻena o ke ānuenue. No laila, I ka manawa o ke kūlana lā ma lalo i ka lewa, aia ke ānuenue i ke kūlana kiʻekiʻe i ka lewa. Eia kekahi, I ka manawa o ke kūlana lā kiʻekiʻe i ka lewa, aia ke ānuenue i ke kūlana lalo i ka lewa. E nānā ʻia ia kiʻi:
How does the rainbow appear?
In order for the rainbow to appear, you need 3 things within the atmosphere. As for these things:
-
The sun needs to be at a proper angle
-
The needs to be behind the observer
-
The correct size of the water droplets in the air
Many and colorful are the rainbows here in Hawaiʻi, because, the sun and the water droplets are plentiful.
As a result of the reflection and refraction of the sunʻs rays within the water droplets in the sky the rainbow appears. Therefore, In order for us to see the rainbow, the water droplets are located suspended in the sky. Namely the water droplets in the clouds, the fog, or the misty vapor. Look at the figure below. At the time the sun ray enters a water droplet, it is refracted due to the density of the water, namely the density of the water is greater than the density of the air. The mathematics of this effect are Snells law. As a result of the sunʻs ray being refracted in the water droplet, the white light is separated into 7 colors. On the back of the water droplet every color is reflected. The colors are again refracted when they leave the water droplet.
Here are the colors of the rainbow: red, orange, yellow, green, blue, indigo, violet. The red is located on the top of the rainbow and the violet is on the bottom. If you look at the figure, the red color departs the water droplet on the bottom and the violet on the top, however, the red is located on the top and the violet on the bottom of the rainbow when seen. Why this changing in the order o the colors?
The geometry is the answer. The top of the rainbow appears at the angle of 42 degrees from the observer and since, the refraction of the violet color is greater than the red color, we only see the red color from the water drops at the top of the rainbow. The other colors pass above the eye of the observer. The base of the rainbow appears at the angle of 40 degrees. Since, the refraction of the red color color is less, we only see the violet color from the water droplets at the base of the rainbow. The other colors pass below the eye of the observer. This effect can be seen in the figure below. As a result of the movement of the sun and the angle of 42 degrees from the observer at all times, the refraction position of the rainbow changes. Therefore, when the position of the sun is low in the sky, the rainbow is at a high position in the sky, Furthermore, when the sunʻs position is high in the sky, the rainbow is at a low position in the sky. See the figure.
References:
I1. Iosepa Nawahī. (1893, May 24). Ke Ānuenue a me Ka Luakalailani. Ka Leo o ka Lāhui, pp. 2-3
2. Carl B. Boyer (1987). The Rainbow: From Myth to Mathematics. Princeton, NJ: Princeton University Press.
3. Steven Businger (2020). The Secrets of the Best Rainbows on Earth. University of Hawaiʻi at Mānoa. Honolulu, HI: to be submitted to the Bulletin of the American Meteorological Society.
Photo by: Tianne Alegnani