Fatamorgana
(Sumber: Sregar, MS. 1991. Udara Dalam Kehidupan Bandung: KaryaIndah.)
Apakah fatamorgana itu?
Biasanya fatamorgana dapat kita lihat di jalan aspal dan gurun pasir ketika matahari terik. Cobalah kalian berdiri ditepi jalan beraspal pada saat matahari terik. Pandanglah kea rah sepanjang jalan beraspal itu. Apa yang dapat kalian saksikan?
Di jalan beraspal itu akan Nampak sinar berkilau-kilauan, melindak-lindak seperti air, bukan? Kejadian itulah yang kita sebut fatamorgana.
Fatamorgana termasuk salah satu penipuan mata. Sesungguhnya apa yang kita lihat itu sebetulnya tidak ada. Cobalah kalian dekati air yang Nampak melindak-lindak di atas permukaan aspal itu! Tidak ada, bukan?
Peristiwa terjadinya fatamorgana berkaitan erat dengan keadaan cuaca. Adanya penyinaran matahari terhadap muka bumi menyebabkan suhu udara di sekitarnya berbeda. Udara yang lebih dekat dengan jalan beraspal memiliki suhu yang lebih tinggi dari suhu udara di atasnya. Hal ini dsebabkan udara di atas jalan beraspal menerima panas dua kali. Satu kali dari penyinaran matahari dan satu lagi dari jalan beraspal. Jalan beraspal dapat menyerap dan menyimpan panas matahari dalam waktu tertentu.
Timbulnya perubahan suhu udara membuat udara di jalan beraspal lebih renggang dari pada udara di atasnya. Akibatnya sinar matahari yang datan dari atas dibiaskan dulu sebelum mencapai muka bumi. Dibiaskan maksudnya diteruskan dengan arah yang berubah. Peristiwa pembiasan sinar terjadi apablia sinar itu datang melalui kerapatan udara yang berbeda.
Dalam hal ini sinar matahari datang melalui udara yang lebih padat menuju udara yang lebih renggang di atas permukaan jalan aspal itu. Akibatnya sinar matahari dibiaskan menjauhi garis normal. Garis normal adalah garis tegak lurus pada bidang batas antara kedua lapisan udara yang kerapatannya berbeda.
Suatu ketika sinar bias mencapai sudut batas. Sudut batas adalah sinar bias yang sudut biasnya sudah mencapai 90o. sudut bias merupakan besarnya sudut yang dibentuk sinar bias dengan garis normal. Dalam hal ini sinar matahari akan dibiaskan sejajar atau berhimpit dengan bidang batas.
Setelah itu sinar-sinar datang berikutnya tidak dibiaskan lagi. Tapi akan dipantulkan sempurna ke mata kita. Akibatnya kita tidap dapat melihat permukaan aspal lagi, melainkan di atas permukaan jalan beraspal itu kita melihat gejala fatamorgana.
Sebetulnya gejala fatamorgana lebih banyak ditemukan di daerah gurun pasir. Zaman dahulu, orang-orang yang ditengah padang pasir sering tertipu karena gelaja fatamorgana ini. Pada saat kehabisan bekal air diperjalanan, mereka mencoba mencari mata air. Mula-mula mereka sangat bergembira melihat adanya gejala fatamorgana itu. Mereka bergegas mencapai tempat kejadian fatamorgana itu. Mereka bergegas mencapai tempat kejadian fatamorgana. Tapi makin mereka mendekat, gejala fatamorgana itu pun semakin menjauh. Akhirnya mereka keceewa, tanpa menemukan mata air yang diharapkan.
Sesuai dengan perkembangan ilmu pengetahuan, maka kejadian seperti itu tidak perlu terjadi lagi. Dewasa ini orang tidak mau lagi terkecoh akan adanya gejala fatamorgana. Orang sudah tahu bahwa gejala itu hanyalah penipuan mata belaka, sebagai akibat adanya pembiasan sinar matahari oleh udara.
Demikian, sedikit uraian tentang fatamorgana. Semoga uraian singkat ini berguna untuk ita semua. Sekaligus menyadari betapa pentingnya atmosfir bagi kehidupan kita.
IN ENGLISH (with google translate Indonesian-english):
Mirage
(Source: Sregar, MS., 1991. Bandung Indoor Air Life: KaryaIndah.)
Is it a mirage?
Usually we see a mirage in the desert pavement and when the sun is blazing. Try you stand on the edge of the paved road at the blazing sun. Look along the paved road towards it. What can you see?
On a paved road that will sparkle-sparkle light appears, melindak-lindak like water, is not it? Genesis is what we call mirage.
Mirage including one eye scams. Indeed, what we see is actually not there. Try to approach your water-lindak melindak appears above the surface of the asphalt it!No, do not you?
Mirage event of closely related weather conditions. The presence of solar radiation on the earth causing the surrounding air temperature is different. The air is much closer to paved roads have a higher temperature than the temperature of the air above it. This dsebabkan air over hot asphalt road receives twice. One time from solar radiation and one from a paved road. Paved roads can absorb and store the sun's heat in a specified time.
The emergence of changes in air temperature and the air on a paved road is more tenuous than the air above it. As a result of compaction of sunlight refracted before reaching the earth. Refracted intention forwarded to the direction of the change. The incident happened apablia light refraction rays coming through the air density is different.
In this case the sunlight coming through the air is more dense towards a more tenuous air above the asphalt road surface. As a result, sunlight is refracted away from the normal line. Normal line is perpendicular to the boundary between the two layers of air of different densities.
Once the light reaches the corner boundary bias. Beam angle is the limit bias bias has reached 90o angle. bias angle is the angle formed by the amount of light with the normal bias. In this case the refracted rays will parallel or coincide with the boundary.
After that the rays are not refracted again come next. But it will be perfectly reflected into our eyes. As a result we can see the surface of the asphalt tidap again, but on the surface of a paved road that we have the phenomenon of mirage.
Actually mirage symptoms were more common in the desert. Ancient times, the people in the middle of the desert are often fooled by this mirage gelaja. At the time of running water supplies along the way, they try to find a spring. At first they were very happy to see any symptoms that mirage. They quickly reached the scene it was a mirage. They quickly reach the scene mirage. But the more they approached, the mirage phenomenon that was further away. Finally they keceewa, without finding the expected spring.
In accordance with the development of science, so something like that does not need to happen again. Today, people no longer want to be fooled any symptoms mirage. People already know that the symptoms were just scams naked eye, as a result of the refraction of sunlight by air.
Similarly, a little description of mirage. Hopefully this brief overview is useful for ita all. Once realized how important atmosphere for our lives.
(Source: Sregar, MS., 1991. Bandung Indoor Air Life: KaryaIndah.)
Is it a mirage?
Usually we see a mirage in the desert pavement and when the sun is blazing. Try you stand on the edge of the paved road at the blazing sun. Look along the paved road towards it. What can you see?
On a paved road that will sparkle-sparkle light appears, melindak-lindak like water, is not it? Genesis is what we call mirage.
Mirage including one eye scams. Indeed, what we see is actually not there. Try to approach your water-lindak melindak appears above the surface of the asphalt it!No, do not you?
Mirage event of closely related weather conditions. The presence of solar radiation on the earth causing the surrounding air temperature is different. The air is much closer to paved roads have a higher temperature than the temperature of the air above it. This dsebabkan air over hot asphalt road receives twice. One time from solar radiation and one from a paved road. Paved roads can absorb and store the sun's heat in a specified time.
The emergence of changes in air temperature and the air on a paved road is more tenuous than the air above it. As a result of compaction of sunlight refracted before reaching the earth. Refracted intention forwarded to the direction of the change. The incident happened apablia light refraction rays coming through the air density is different.
In this case the sunlight coming through the air is more dense towards a more tenuous air above the asphalt road surface. As a result, sunlight is refracted away from the normal line. Normal line is perpendicular to the boundary between the two layers of air of different densities.
Once the light reaches the corner boundary bias. Beam angle is the limit bias bias has reached 90o angle. bias angle is the angle formed by the amount of light with the normal bias. In this case the refracted rays will parallel or coincide with the boundary.
After that the rays are not refracted again come next. But it will be perfectly reflected into our eyes. As a result we can see the surface of the asphalt tidap again, but on the surface of a paved road that we have the phenomenon of mirage.
Actually mirage symptoms were more common in the desert. Ancient times, the people in the middle of the desert are often fooled by this mirage gelaja. At the time of running water supplies along the way, they try to find a spring. At first they were very happy to see any symptoms that mirage. They quickly reached the scene it was a mirage. They quickly reach the scene mirage. But the more they approached, the mirage phenomenon that was further away. Finally they keceewa, without finding the expected spring.
In accordance with the development of science, so something like that does not need to happen again. Today, people no longer want to be fooled any symptoms mirage. People already know that the symptoms were just scams naked eye, as a result of the refraction of sunlight by air.
Similarly, a little description of mirage. Hopefully this brief overview is useful for ita all. Once realized how important atmosphere for our lives.
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