Selasa, 25 Agustus 2020

Biografi Ir. Rachmad Mohamad n.i., Pioneer Jurusan Fisika Teknik di Indonesia

            Ir. Rachmad Mohamad n.i. adalah salah satu pioneer bagi perkembangan jurusan Fisika Teknik/Teknik Fisika di Indonesia. Beliau adalah alumnus Technische Hogeschool (TH) Delft, fakultas (perguruan tinggi) teknik pertama di Indonesia yang didirikan setelah Perang Dunia I. Beliau pada awalnya mendaftar di Jurusan Elektro. Namun setelah itu beliau sering berindah-pindah jurusan. Karena minatnya pada riset dan penelitian, beliau pindah dari Jurusan Elektro ke Teknik Kimia. Setelah Jurusan Fisika Teknik didirikan, karena minatnya tersebut, beliau akhirnya pindah ke Jurusan Fisika Teknik.

            Beliau berpendapat bahwa setiap bangsa mesti melakukan baik kegiatan rutin maupun kegiatan ilmiah. Kalau tidak, maka bangsa itu tidak akan pintar. Apabila dibandingkan dengan negara seperti Jepang dan negara-negara Eropa, kita terlihat kurang pintar. Hal itu disebabkan mereka gemar melakukan kegiatan ilmiah. Menurut beliau, kegiatan ilmiah inilah yang perlu ditunjang. Kegiatan ilmiah tersebut diwujudkan dalam suatu riset.

             Fisika Teknik menurut beliau adalah sebuah kajian untuk menghasilkan orang-orang yang terdidik secara ilmiah di bidang keteknikan. Beliau mengungkapkan bahwa jurusan-jurusan teknik lainnya seperti Elektro, Mesin, dan Sipil, di aplikasi yang lebih tinggi membutuhkan orang-orang yang pikirannya basically Physics. Beliau mencontohkan pada peristiwa pendaratan di Bulan oleh Amerika Serikat pada tahun 1969 yang membutuhkan orang-orang terdidik dengan pemahaman yang kuat pada konsep fisika untuk membuat kendaraan yang bisa berjalan di Bulan. Hubungan antara ilmu murni yang dipelajari oleh Jurusan MIPA dengan jurusan keteknikan adalah sesuatu yang penting. Ketika orang dari Jurusan MIPA mencetuskan ide baru (berupa teori), tugas orang Jurusan Teknik yang mengaplikasikan. Teori tanpa instrumentasi adalah nonsense menurut beliau. Fisika Teknik adalah jurusan yang menjembatani kedua hal itu.

            Beliau adalah salah satu orang yang berjuang untuk eksistensi dan kemajuan Jurusan Fisika Teknik di Indonesia. Beliau termasuk salah satu dari lima mahasiswa pertama Fisika Teknik di Indonesia. Pada waktu ia masih belajar di Indonesia, tempat ia belajar, TH Delft, adalah sebuah kerjasama antara Indonesia dengan Belanda. Dosen-dosen di jurusan itu adalah orang Belanda yang notabene memiliki pengetahuan instrmentasi, akustika, dan bidang-bidang keteknikan Fisika lain yang belum dimiliki orang di Indonesia. Namun pada masa pengusiran orang Belanda dari Indonesia (sekitar tahun 1957-1958), dosen-dosen itu pun turut terusir. Mahasiswa Fisika Teknik pada saat itu mau tidak mau harus ke luar negeri jika ingin melanjutkan pendidikannya. Maka dari itu, beliau melanjutkan pendidikannya ke Belanda dengan beasiswa dari perusahaan minyak De Bataafsche Petroleum Maatschappiy.

            Sepulangnya dari Belanda, beliau menjadi dosen luar biasa dan setelah itu dosen tetap di ITB. Beliau adalah orang yang mendirikan intrumentasi pertama di ITB. Kemudian, setelah ditawarkan bantuan dari Belanda (saat itu berada pada masa Orde Baru), beliau meminta didirikan instrument center yang akhirnya menjadi Lembaga Instrumentasi Nasional (LIN) yang berada di ITB. Setelah itu terdapat perpindahan tempat LIN beberapa kali. Sampai akhirnya LIN berpindah dari wewenang ITB, karena kurangnya apresiasi terhadap kegiatan ilmiah, ke tangan Lembaga Ilmu dan Pengetahuan Indonesia (LIPI). Beliau pun yang pada saat itu menjabat sebagai wakil direktur LIN harus memilih antara ITB atau LIPI. Akhirnya beliau dipecat dari jabatan itu karena memilih ITB.

            Beliau selalu menekankan akan pentingnya hubungan antara riset dan praktikum. Kembali mengutip perkataan beliau bahwa teori tanpa instrumentasi adalah nonsense, maka dapat diartikan juga riset tanpa praktikum adalah nonsense, vice verca. Maka dari itu adanya sarana dan prasarana untuk memfasilitasi sebuah bidang keilmuan untuk penelitian adalah krusial. Penekanan tersebut didasarkan bahwa seharusnya mahasiswa tidak boleh dipaksa untuk menerima mentah-mentah teori-teori yang diajarkan. Menurutnya, inti dari semua pendidikan itu adalah mengabdi pada kebenaran, yang didapat dari observasi. Jadi, bagaimana bisa menjadi insinyur research yang baik kalau tidak memiliki pengalaman? Bagaimana dapat mendidik sarjana-sarjana Fisika Teknik yang bermutu tanpa laboratorium? Nonsense.  

 

Daftar Pustaka

1.      Suyatman, et al. (2004). Engineering Physics : Antara ‘Fisika Teknik’ dan ‘Teknik Fisika (1st ed.). Bandung : Departemen Teknik Fisika ITB.

           

 

Rabu, 22 Mei 2019

Moonwalking with Einstein; The Art and Science of Remembering Anything


Resume by      : Maulana Alif Asy-Syahrani
Title                 : Moonwalking with Einstein; The Art and Science of Remembering Anything
Author             : Joshua Foer
Publisher         : The Penguin Press
Pages               : 269
E-ISBN             : 978-1-101-47597-3

            It all began when Josh went for an interview with a theoretical physicist at Kutztown University. On the way there, through York, Pennsylvania; he didn’t waste his chance to visit the Weighlifting Hall of Fame and Museum. It turned out that it was anything but old photograph collections of Weighlifitng. It didnt’t seem like thing that will linger in mind, except for a photograph of a man named Joe “The Mighty Atom” Greenstein. When he noticed the label “the strongest man in the world, right next to Greenstein’s photograph, it came to his mind that it would be interesting if the world’s mightiest man ever got to meet the world’s smartest person. But it won’t be as choosing for the muscle category, it would be rather more difficult to choose for “smart” criterias.

            When Josh browsed for the smartest person in the world, he got plenty of them. Let’s say like the person who can do rubriks on such very fast time, the person who can multiply many digits number just for a second, high IQ person who lived in New York, or the people like Albert Einstein or Stephen Hawking. There was someone he put his interest in. He was Ben Pridmore, a man who can remember 1,528 random digits in an hour and also any poem given to him. He was the conqueror of the world championship of memory.

            Josh kept thinking about Ben Pridemore and what he said on a newspaper article, “anyone could do it, really” along some times. It eventually led him to attend the 2005 U.S. Memory Championship which was held at Con Edison headquarters in Manhattan. This time, he went there also due to a job to write an article for Slate magazine.

            There were five events in this championship, such as poem remembering, memorizing ninety-nine photographic head shots with their first and last name of the person, memorizing three hundred random words, memorizing a page of random digits, and memorizing a random order of a set of bridge cards. Looking down at what the contestants were doing, he was amazed by how they could do that. Then he came to an England young Grand Master named Eddie Cooke. He told Josh that they weren’t savant nor having some kind of photographic memory, he rather admited that he and every one in there were just like any other ordinary person. It was only that mnemonist, the term for them or they usually call themselves as “mental atheletes”, maximized their brain potential to a higher level. As Ben Pridmore put it, we had to “think it in a more memorable way.”

            Ed explained that they were using a kind of memory technique called “memory palace”. He explained that it was an ancient technique invented by a Greek poet named Simonides of Ceos. It recorded in history that Simonides first discovered this technique after a tremendous disaster that occured in a party he came in. He closed his eyes and started visualized how condition before the disaster happened. He managed to precisely put almost everything in place and after that he reported it for identifying purpose. So, the technique is focusing on the materials that are meant to memorize and put them in a place in mind called loci. Whenever a person wants to recall for that things, he just has to visualize the place and starts looking for one piece after another.

            After some chats, Ed told that his very pupose was to revolutionize, or in this chase is to restore, the education system of the western. Apart form his party-guy attitude, he thought that the west education system had became so corrupted. In the past, people used to store almost everything now we have in books, records, etc. in their head. As human discovered how to externalize informations, the art of memory gradually faded. With the method he had, he had this thought of making the better thing, especially education for other people. It’s the same thing when Josh met the person behind the championship and the leader of this around-the-globe memory training movement, Tony Buzan.

            Tony Buzan was an infamous, sixty-seven year-old, person of brain developmental world who get his fame from his method he advertise all over the world. Josh got the chance to have chats with him in Con Edison’s cafetaria. Not so different with Ed, he told Josh that it is important for people to restore the art of memory, like what people of the past had taken the art for granted. He told Josh that he took the concerns of the brain potential. Some things he had done were such as establishing memory championship in some countries, teaching and now had found a memory training foundation, and promoting many other things related to memory.

            The most important thing he emphasized was about revolution of education. He thought that the education system at the time was all about putting a lot of information into students brain through rote-dead-drill method. It’s not effective and killing the creativity. It’s very important as well to teach students not only what to learn, but also how to learn. Josh wondered what it was like to have the ability of those mental atheletes. So, Buzan encouraged him to try it himself, by joing the championship too!

            He came away from the championship inclined to do some short of research. His findings on memory stuffs consisted of the history about memory and the extreme cases on people. He concluded from the sources he explored that actually the method the mental athletes refered to had long time ago been used by the ancient civilization, especially when there was still a minimum use of ‘external’ memory.

            Like as it is part of human evolution, storing information from mind to a spescific mean also got it way through the time. It was said to begin when people started painting pictures on cave walls. These pictures later simplified and generalized into symbols like what the Egypt did. As symbols grew into letters, letters into complex and abstract words, words into sentece, and the brilliantly invented space between words and the addition of word marks. As what is stored improved, so did its media. Before book, people used papyrus leaf to carry out what they wrrote. To make it as portable as possible, they turned it into scrolls. It wasn’t that easy to find a certain information in many through scroll. That’s why the data converting was meant not to be ultimately the tool to replace our memory. It was just a media to store the data so it was likely possible to maintain. The human’s memory function had been changed from a completely data storing media into an indexing tool for information.
            When people invented the way to put those letters out of scrolls to flipped books, they also accomplished one more way to reduce its inefectiveness, the table of content. And then, at the industrial era, the production of books was greatly increased. It made the distribution of book vastly increased as well. Before it happened, book was viewed as something luxurious and not everyone could have it. Until now, the externalization of memory has reached a very different level from years than the past millenials. Those improvements makes life easier but, in return, we now has our memory quality detoriating.

            After that championship too, Josh got a better chance to know Ed better. One day he made an appointment with Ed to follow him teaching in a certain highschool as his trip to promote (as for advertise himself as memory trainer) after the championship before he headed back to England. He told Josh to follow him if he wanted to know more about this memory things. So Josh followed Ed all day long teaching in highschools and ended up in a bar. They were chating some conversation as Josh were digging down about Ed. When Ed discovered Josh’s passion in memory, he was willing to serve as Josh’s mentor in memory training, as he also encouraged Josh to join in the U.S Championship.

            As part of Josh research to understand human memory better, he came to Tallahassee to helped a group of Neuroscientist led by Anders Ericsson to be a subject of their test. So Josh was asked to be tested with a set of cognitive tests, which consist of general knowledge test, memory test, and so on; at the time and later after his memory training (after the championship he planned to join). The test was held in the group place called Human Performance Lab.

            As Josh continued his research, he found in a Russian neuroscientist, A. R. Luria’s journal, a person who had a unique case on remembering. It was S (initial only as in medical journal rules), a journalist, who had a rare case which he could retell everything that’s experienced by him. He just simply barely forgot. As it was turned out that the everything that comes to S’s memory seemed to directly stored up to the long-term memory with a unique mechanism. He admited that whenever he wanted to recall something, he got this visualization of a street where he lived and put the thing he wanted to remember on particular place. What he did is just like what the mnemonist does, but in his case he could do that naturally. So basically, the mental athletes, who are not as extraorndinary as S, are trained to the limit to memorize like S.

Later on, S was also diagnosed with a syndrome called synesthesia, a condition when an information recieved by a sense can be intepreted into the other senses, for example if S were shown the number 9. He would imidiately sense the feeling of sweet, rough, and hard. As well as if he did it with his other senses. With that condition, it allowed him to greatly make the difference of the quality of memory he made compared to ordinary person. Having a great capacity of memory is one thing many people wish as it will help out get things easily, but what S was undergoing is not like that. It was hard for him to eliminate something he remembered but he wasn’t willing to remember. Moreover, he could barely distinguish whether an information is important or just trivial.

Contrary to S case, what about the person who forget things as extraordinary as in proportion to S memorize things? Josh was able to make a chance to find one example directly. He made contact with Larry Squire, a neuroscientist from University of California, to get a chance to meet his research subject. As the counterpart of S, a eighty-four-year-old man with the initial EP was the man with very bad forgetfulness. He couldn’t hold a memory long enough from one conversation to a new one. From Larry’s diagnosis, EP’s brain was impaired with a herpes simplex virus attack which crumbled down his neo-cortex and hippocampus area. This fact helped the scientist to understand the system of remembering. The mechanism goes like this, when a new memory is written in our brain it first stays in our short-term memory. It will take some repetition or a certain condition before it transfered into our long-term memory. Without the hippocampus that EP had problem at, the memory only stays for some short of time before it completely disapears.

But as though EP short-term memory was unlikely to be able to be stored in the long one, he still maintained his memory thirty years ago from that time. Also, what had been done by EP as habits in the time he had already been easily forgeting, though he couldn’t remember, he managed to perform the exact same thing the other time. For example when he strolled around the neighborhood. He could manage to get back to his house while also greeted his neighbour along the way which he in his thought always recognized as a new person he’d never met before. With EP’s condition, it seems very hard to live the life but we won’t even care about that because what in the world we will think nor what we care about. A life without a single memory that gets stay long enough for us to comprehend will let us live a happy life, like what EP experienced.

            After a while, Eddie swanted to get back to his country. Before that, Josh had promised him to take him to the Central Park where Ed’d never gone before. There, Ed began his training to Josh. He introduced him the method of loci or the memory palace though the classic manual, Ad Herennium. It took Josh to concentrate deeply into his mind. Ed gave him some trick he usually does in daily life that uses the memory palace. He picked some random words out of his memory, his to-do-list that day. He wanted Josh to remember it too. He told Josh to think about a place served as the palace that would be used as the place to store up the list. Then, he told Josh to put the list in order in spesific place in his palace (Josh’s palace was his childhood house) with exageration. He told Josh that the wilder, odd-er, and nastier the thing asociated with what was wanted to memorize, the more lingering the thing would be. Josh was so impressed that he could renounce the list back easily.

            It took Josh a lot of practice with the method Ericsson recomended him to do, the deliberate practice. The method was to be as efficient in practice in such amount of time. It was meant so Josh could be continously developing, without being trapped in the ok plateu. When a person has reached his ok plateu, that person does a particular activity without realizing it, or in another word being in auto-pilot. It’s the condition that keeps, let’s say, a driver that has been spent ten years driving without any improvement compared to his driving five years ago. It is also what distincts a mediocre sportman with the very good one. While the ordinary player keeps playing the game over and over, the better one is focusing his practice on a certain movement that he has to master to overcome the game.
            Josh training brought him to Ed’s homeground in Oxford, England. There, Josh wanted to learn more from Ed the latest technique for different events which were competed on the last U.S. Championship, as he also wanted to watch the more competitive memory championship in that town which Ed and Ben Pridemore took part in. The memory championship in europe had been viewed as way more competitive rather the one that is held in U.S. As it turned out, the result of the event was quite surprising. Ben only finished on the fourth place, while Ed couldn’t even make it into big ten.

            After coming back from England, Josh took most of his spare time practicing for the championship. Month after month, he made a promising progress. Sticking to the methods he had from Ed and Ericsson, and also with the help of a software that could track his progress, he was sure he got a chance on the champioship, though the other competitor seem to be more experienced than him.
            One thing he that came to Josh’s mind when recalling the last memory championship he saw was that he also found out that the mnemonic method was used by Ramon Matthew, a history teacher at a church school which was one of Tony Buzan’s diciples. He thought that with this method he could help to bring up the education into a better level. But it left contradictory with the principle that Tony Buzan had. In Buzan’s point of view, the education system shouldn’t be necessarily judging the students by one parameter and on certain level it can be helped with enhancing the memory capacity with creativity, the two things that seems contradictory in the past education system but now has got it’s way to a better understanding that those two things are unseperatable. To get to know better about it, while also on an occasion for his job, he flew to England again to attend Ed’s twenty-fifth birthday party and also to visit Buzan’s home near the Thame River.

            It had been a year since the first time Josh knew about mnemonic world and now he stood on the stage as one of them. This time, like never before, there were additional events for the big six who made it through the four classic events–names and faces, speed numbers, speed cards, and poem. The classic events took time inthe morning session, after that, the big six would compete in an three elimination round that were also aired on national channel. Josh had a surprise upon himself that he could make it to the main event by the second position, and even broke the U.S. record for the speed cards event. The other five contestants who also made it to complement the big six were Maurice Stoll for the first place, whom Josh had been worried about; Chester Santos for one place behind Josh, who got a problem with Josh because of the article Josh wrote about last year’s championship; Ram Kolli, the defending champion; Paul Mellor, a forty-seven years old marathoner; and Erin Luley, who also set a record for the poem.

            The main event consisted of “Words to Remember”, then continued with “Three Strikes and You’re out of the Tea Party”, and “Double Deck’r Bust”. First of all the six of them gathered in a circle and memorized random words that were handed to them. After that they, one-by-one, each called out the next word on the words list they’d memorized. The first two contestant who miss a word would be knocked out. Those first two were Erin and then Mellor.

Next, they got into the next event, the tea party which apparently became Josh’s worst part. In this event, five strangers, posing as guest at a tea party walked onto the stage and tell information about themsleves which the contestant should memorize. The rule for this event was that the first two contestants to forget three pieces of information would be knocked out. This time Maurice and Chester had to leave the stage.

The last battle of mind was set before the two finalist, Josh and Ram. They had to memorize the same two decks of bridge card. In the ten minutes pause before the grand finale, as Maurice stepped off the stage, he congratulated Josh not for his accomplishment for the finale but rather for winning the championship which he hadn’t done. He said to Josh that Ram was prety bad at cards. The same thing went from Ben as he were there speculating the championship like what he usual does. And what they told Josh was true. When it was decided for Ram to recite first, he stop it only at the fifth card. That was it! Without Josh even said a single word at the last event, he was the new U.S. memory champion.
           
           
           

Senin, 26 Februari 2018

Bunga Bank (Bank Interest)



Oleh: Maulana Alif A-S



Pengertian     

Bunga bank, atau bank interest, merupakan kompensasi terhadap jasa dari peminjam dana kepada pihak yang telah meminjamkan sejumlah uangnya. Imbal jasa tersebut dapat berupa perhitungan persentase pokok utang dan lamanya waktu peminjaman yang dihitung secara periodik. Selain cara tersebut, bunga dapat juga dihitung dengan tingkat bunga yang dikenakan terhadap pinjaman. Sebagai contoh, Anda meminjam uang sebanyak Rp100.000,- dengan bunga tunggal 2% tiap tahunnya dari bank. Ketika Anda hendak mengembalikan uang tersebut pada setahun berikutnya, jumlah yang harus dibayarkan adalah uang yang Anda pinjam (Rp100.000,-) ditambah bunga yang diberikan dalam setahun (2% x 1 tahun x Rp100.000,- = Rp20.000,-). Jadi total uang yang harus dikembalikan adalah Rp120.000,-.
            Selain dalam hal pinjaman kepada bank, bunga bank juga dapat ditemui ketika kita menyimpan (mendeposit) sejumlah uang pada sebuah akun bank. Dalam hal ini, kita yang mendepositkan uang kepada bank dapat diibaratkan sebagai peminjam dana dan bank berperan sebagai peminjam. Uang tersebut biasa dipakai oleh bank untuk dipinjamkan kembali kepada nasabah yang lain. Bunga yang kita dapatkan bergantung pada persentase yang disebut suku bunga atau interest rate. Misalnya, Anda menyimpan Rp250.000,- pada saat suku bunga tunggal 5% dalam satu tahun. Setelah enam bulan, uang Anda bertambah menjadi Rp256.250,-. Besarnya suku bunga dapat dipengaruhi oleh banyak faktor, seperti kebutuhan dana, target laba, jaminan, kebijakan pemerintah, jangka waktu periodik, reputasi perusahaan, persaingan, dan sebagainya. Selain itu, besar suku bunga juga mempengaruhi minat masyarakat untuk menyimpan uangnya pada bank. Hal-hal tersebut tersirat dalam pengaruh hukum permintaan dan penawaran serta teori Keynes tentang liquidity preference.
           

Sejarah dan Pandangan

Menurut tulisan Paul Johnson, seorang sejarawan, peminjaman dengan bunga sudah biasa dilakukan sejak awal 5000 SM di Timur Tengah. Pada saat itu orang-orang masih menggunakan sistem barter dalam kesehariannya. Maka dari itu lAndasan yang dipakai merupakan argumen tentang biji-bijian dan binatang yang menjadi kebutuhan pada masa itu. Biji-bijian dan binatang dapat mereproduksi diri mereka sendiri, sehingga kebijakan untuk menambahkan nilai saat mengembalikan pinjaman menjadi awam. Namun pada tahun  2500-an SM di negara-negara Timur Tengah seperti Mesir, Sumeria (Iraq selatan), Asyur (Iraq utara) perak sudah awam digunakan sebagai alat tukar. Perak yang berupa logam tidak dapat dikembangbiakan. Ini menyebabkan sistem bunga tersebut menjadi tidak lagi valid.
            Hal tersebut sebenarnya telah menjadi concern dari banyak pAndangan, mulai dari pAndangan tradisi, pAndangan filsafat, serta pAndangan ilmiah. Tradisi Yahudi kuno melarang hal tersebut karena dianggap sebagai riba (usury) (lihat Ulangan 23 : 19-20). Karena sistem tersebut merupakan produk dari perkembangan ekonomi di masyarakat, larangan terhadap sistem tersebut memberi pengaruh keagamaan pada masyarakat. Para raksasa filsafat seperti Plato dan muridnya Aristoteles juga memberikan pendapat negatif terhadap penggunaan sistem ini. Lalu pAndangan oleh dua agama terkemuka saat ini, Kristen dan Islam, juga melarang adanya penambahan bunga.
            Konsili Nicea pada tahun 325 M  memutuskan bahwa riba di atas 1% perbulan bagi para kaum kependetaan. Aturan ini sempat diaplikasikan di Itali pada abad ke 9. Pada era di mana tumbuh kaum terpelajar atau era skolastik pAndangan tersebut semakin kuat. Namun di  masa yang sama, muncul sebuah gagasan bahwa riba dan bunga merupakan dua hal yang memiliki definisi berbeda. Letak perbedaannya adalah apabila seseorang meminjamkan dengan sistem bunga, orang tersebut juga turut mengambil resiko yang sama dengan peminjam. Lalu, tokoh filusuf kristen terkemuka Thomas Aquinas justru juga mengambil sikap negatif terhadap sistem bunga. Beliau memAndang bahwa sistem bunga salah karena melipatgAndakan pengembalian pinjaman.
             Sedangkan dalam Islam tertulis dalam Al Quran terdapat tujuh ayat yang mengandung aturan tentang riba. Seluruh ayat-ayat tersebut menyatakan bahwa riba merupakan sesuatu yang harus dijauhi karena merupakan pantangan. Contohnya dalam surat Al Baqarah (2) ayat 275, tercatat bahwa riba merupakan sesuatu yang haram dilakukan. Persoalan bunga bank yang dianggap sebagai riba telah menjadi perdebatan di kalangan pemikir dan fikih Islam. Model bank yang konvensional diubah ke dalam bentuk syariah sebagai penyelesaiannya. Pada pertengahan tahun 1900-an merupakan kebangkitan bentuk bank tersebut. Sistem bunga bank digantikan oleh sistem bagi hasil yang dianggap lebih syariah.
Hal
Sistem Bunga
Sistem Bagi Hasil
Penentuan besar hasil
Sebelumnya
Sesudah ada untung
Yang disepakati
Bunga, besar nilai rupiah
Proporsi pembagian untung untuk masing-masing pihak, misalnya 50:50, 60:40, dst
Jika terjadi kerugian
Ditanggung nasabah
Ditanggung kedua pihak
Pokok penghitungan
Pokok utang, tetap
Untung yang diperoleh, belum tentu nilainya
Titik perhatian proyek/usaha
Besarnya bunga harus dibayar nasabah/pasti diterima bank
Keberhasilan proyek/usaha merupakan perhatian bersama
Besarnya
Fixed: % kali jumlah pinjaman yang pasti telah diketahui
Proporsi: % kali jumlah untung yang belum diketahui
Menurut Al Quran
Melawan QS 13: 34
Melaksanakan QS 13:34
Tabel perbandingan sistem bunga dengan sistem bagi hasil
Sumber: M. Syafe’i Antonio. 2001. Bank Islam Teori dan Praktik, Jakarta: Tazkia Institute




Metode Perhitungan


·         Suku Bunga Tunggal (Simple Interest)

Hasil gambar untuk suku bunga tunggal rumus
Perhitungan bunga tunggal didasarkan hanya pada jumlah pokok atau jumlah yang terakhir. Contohnya dapat dilihat di bagian awal tulisan ini.

·         Suku Bunga Majemuk (Compound Interest)

Hasil gambar untuk suku bunga majemuk rumus


Dalam perhitungan ini jumlah pokok yang berbunga selalu mengalami perubahan tiap periode pertambahan nilai saldo. Artinya, bunga dalam sistem ini mengalami pembungaan setiap periodenya. Jumlah bunga otomatis akan terus bertambah. 


Perhitungan Yang Sering Digunakan di Indonesia


1.      Perhitungan metode saldo terendah

Rumusan: Bunga = (Jumlah saldo terendah x suku bunga % x jumlah hari pada bulan laporan)/Jumlah hari dalam 1 tahun.
Contohnya apabila dalam satu bulan Anda melakukan penyetoran awal sejumlah Rp1 juta, maka di awal bulan saldo tabungan terendah terjadi yaitu sejumlah Rp1 juta. Dengan demikian, jika suku bunga tabungan 5% per tahun, maka perhitungan penghasilan bunga bulan tersebut menjadi Rp4.109,59.

2.      Perhitungan metode saldo rata-rata

Saldo, sebagai pokok jumlah, dirata-rata harian yang dihitung dari perubahan saldo dan berapa hari hingga saldo berubah.
Rumusan: Bunga = (Saldo rata-rata harian x suku bunga % x jumlah hari pada bulan berjalan)/Jumlah hari dalam 1 tahun
Misalnya dalam satu bulan terdapat tujuh  kali perubahan saldo sebagai berikut:

Tgl
Setor
Tarik
Saldo
1
1.000.000
-
1.000.000
6
-
1.000.000
5.000.000
10
2.000.000
-
7.000.000
20
-
1.000.000
6.000.000
25
12.000.000
-
18.000.000
30
-
3.000.000
15.000.000

Perhitungan jumlah pokok:
(Rp1 juta x 4 hari) (Rp6 juta x 1 hari) (Rp5 juta x 4 hari) (Rp7 juta x 10 hari) (Rp6 juta x 5 hari) (Rp18 juta x 5 hari) (Rp15 juta x 1 hari) / 30 hari

3.      Perhitungan metode saldo harian

Metode perhitungan ini menghitung bunga yang didapat hariannya selama satu bulan. Ini sama saja dengan mendapat penghasilan bunga setiap hari. Total seluruh bunga yang didapat akan diberikan oleh bank pada akhir bulan tersebut.
Rumusan: Bunga = (Saldo harian x suku bunga % x jumlah hari pada bulan berjalan)/Jumlah hari dalam 1 tahun

Contoh dengan variasi pajak:


Tanggal
Saldo
Jumlah Hari
Bunga Harian
1-3
10.000.000
3
10.000.000 x 5,5% x (3/365) = 4.521
4-5
15.000.000
2
15.000.000 x 5,5% x (2/365) = 4.521
6-14
22.000.000
9
22.000.000 x 5,5% x (9/365) = 29.836
15-16
12.000.000
2
12.000.000 x 5,5% x (2/365) = 3.616
17-27
11.000.000
11
11.000.000 x 5,5% x (11/365) = 18.233
28-30
14.000.000
3
14.000.000 x 5,5% x (3/365) = 6.329

Jumlah bunga selama bulan juni adalah 70,069 (bunga gross)
Pajak bunga tabungan: 20% x 67.056 = 13.411
Jadi bunga tabungan bulan juni yang diterima oleh nasabah: 67.056 – 13.411 = 53.645 


Daftar Pustaka


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