weekend homesick

udah cerita lama kalo tiap weekend msti homesick T.T

Mengapa gelembung sabun berbentuk bulat? *pikir-pikir

ehh ada jawabannya :)
Coba kita pikir begini, Tidak akan terkejutkah Anda bila bentuk gelembung itu persegi? Itu karena semua pengalaman kita sejak bayi mengatakan bahwa hukum alam lebih menyukai bentuk-bentuk yang mulus. Memang tidak banyak benda alami yang memiliki ujung tajam atau membentuk sudut ganjil. Pengecualian yang penting dalam hal ini adalah kristal-kristal mineral tertentu, yang cantik justru karena memiliki bentuk-bentuk geometris serba tajam. Itu mungkin sebabnya mengapa sebagian orang percaya bahwa kristal-kristal dan piramida memiliki supranatural.
Akan tetapi itu metafisika, bukan sains. Gelembung-gelembung bundar–berbentuk bola–karena ada suatu gaya tarik menarik yang disebut tegangan permukaan yang menarik molekul-molekul air sekuat mungkin antara sejumlah partikel adalah ketika mereka membentuk sebuah bola. Di antara semua bentuk yang mungkin, kubus, piramida, bongkahan tak beraturan–bola memiliki luas sebelah luar paling kecil.
Segera setelah Anda melepaskan sebuah gelembung dari pipa tiup atau dari salah satu peralatan lebih modern, tegangan permukaan membuat lapisan tipis air sabun mencari luas permukaan yang sekecil mungkin. Maka terjadilah sebuah bola. Andaikata Anda tidak dengan sengaja memerangkapkan udara didalamnya, air sabun akan terus menyusut membentuk sebuah titik bola padat, seperti yang terjadi pada air hujan.
Akan tetapi udara di dalam mendorong ke arah luar, menahan selaput air. Semua gas memberikan tekanan pada wadah penyimpanan mereka karena mereka terdiri atas molekul-molekul terbang bebas yang terus membentur apa pun yang menghalangi. Dalam sebuah gelembung, gaya-gaya tegangan permukaan ke arah dalam pada selaput air diseimbangkan dengan tepat oleh gaya mendorong keluar oleh udara dari dalam. Jika ada perbedaan sedikit saja, gelembung entah akan mengeceil atau mengembang sampai keduanya sama besar.
Cobalah meniupkan udara lebih banyak untuk membuat gelembung lebih besar. Itu sama dengan menambahkan tekanan udara di sebelah dalam. Yang dapat diperbuat oleh selaput air untuk mengimbangi kenaikan tekanan ke luar adalah memperluas permukaannya. Ini dapat menyebabkan bertambah besarnya gaya-gaya tegangan permukaan ke arah dalam. Maka gelembung itu secara serentak memperbesar ukurannya. Namun dalam proses tersebut selaput air semakin tipis, pasalnya persediaan air memang terbatas. Apabila Anda terus menambahkan udara ke dalamnya, akhirnya selaput tadi tidak memiliki cadangan air lagi untuk memperluas permukaan. Akibat buruknya mulai ditebak. Gelembung-pun meletus.
Hal yang tepat sama juga terjadi pada permen karet, kecuali bahwa ahli-ahli tegangan permukaan ke arah dalam, gaya yang cenderung memperkecil gelembung atau balon berasal dari elastisitas karet dalam permen Anda. Elastisitas, seperti tegangan permukaan, seolah-olah berkata: “Kalau boleh, aku ingin menjadi bola yang sekecil mungkin”.

perahu kertas ^_^

Perahu kertasku kan melaju
Membawa surat cinta bagimu
Kata-kata yang sedikit gila
Tapi ini adanya
Perahu kertas mengingatkanku
Beratapa ajaibnya hidup ini
Mencari-cari tambatan hati
Kau sahabatku sendiri
Hidupkan lagi mimpi-mimpi
(cinta-cinta) cita-cita
Yang lama ku pendam sendiri
Berdua ku bisa percaya

Ku bahagia kau telah terlahir di dunia
Dan kau ada diantara milyaran manusia
Dan ku bisa dengan radarku menemukanmu
Tiada lagi yang mampu berdiri halangi rasaku
Cintaku padamu…

edisi kangen :')

miss u so bad :(
bapak juga :*
lagi apa kalian di rumah ???
biasanya kalo sore2 lg ujan, ibu,aku,sm si lenjeh cunil alias lia :p pasti kmpul smua di kamar ibu trus bapak ikutan nimbrung.. gak mau kalah katanya :-D . hoooo bogopa bogopaseo ..

lagi gandrung ama yg ini nih ^_^

CNBLUE - yonghwa oppa :*

mulai sibuk

huaaah, blog gueh :o , apa kabar ??
walopun gue msh amatir, tapi tetep peduli kok ama blog gue :* (ceileeeh) . sorry kalo lama gak aku tengokin, sekarang sedikit mulai sibuk dgn kegiatan yg baru gue jalanin skitar 1 bln ini ( apa bgt deh -__- sok sibuk ).
tapi seriusan deh, awalnya gue ngrasa gak pantes, gak bisa, takutnya gak bisa mengemban amanah smpe akhir.. kalo awal2nya sih it's okeey. Sana sini blng " gak papa wiwit :) kita percaya kok kmu bisa "
huaaah gmna bisa orng lain prcya sm gue, sdngkan gue sndri aja gak prcya ama diri gue T.T sedihh bgt.
setelah gue renungin (berdiam diri di pojokan kamar tutupan slimut, matiin lampu, matiin kipas angin) akhirnya menyeruat kata " okayy wiwit, fighting, bismillah !!! " akhirnya gue ikhlas deh ngejalanin amanah itu , iya lah secara udh gak bisa diganggu gugat lg keputusannya. So, ya msti ikhlas emang ^o^

Factor that affect the rate of reaction

Factor that affect the rate of reaction, among other :

1.      Touch surface area

To the more surface area touching, so that there will collision more and more. So, the faster is the reaction rate.

2.      Temperature

The higher of temperature, the kinetic energy will be even greater, so that the collision which occurred more frequently and caused faster reaction rate.

3.      Concentration

The greater of the concentration the more substance to react, so the greater the possibility of collisions, consequently the faster reaction.

4.      Catalyst

Catalyst for reaction rate increase which decrease the activation energy of a reaction. Catalyst is added to a reaction to speed up the rate of reaction.

eng-chem

MAKING-UP SOLUTIONS

Analytical solutions are made up in volumetric flasks with volumes ranging from one cubic centimetre to as much as five litres.

Although they are all accurately calibrated, the largest flask will always give a solution with the most precisely measured concentration. This is mainly because any balance has a limit to its accuracy and this will produce a greater percentage error when weighing out smaller quantities of solute. Thus the smaller flasks should only be used when the greatest precision is not required. The very large flasks are used for making up standard solutions of reagents that will be used many times.

Solutions may deteriorate, so standard solutions should never be stored for long periods of time. Furthermore, some solutions may need to be transferred to dark bottles, to limit photochemical decomposition.

A common reason for making up a solution of a solid is to determine the solid's purity or composition - say to determine the percentage copper in this copper salt. The most commonly used flask for this purpose has a volume of 250 cubic centimetres. Like all volumetric flasks, it has a stopper, and a single calibration line which accurately marks the stated volume at room temperature - 20 degrees Celsius.

To determine the purity or composition of a solid, first weigh out a suitable quantity on an analytical balance to an accuraccy of four decimal places. Record the weighing in a notebook. Solids which absorb atmospheric moisture must first be dried in an oven and then allowed to cool in a desiccator, before weighing. Tip the solid into a 100 cubic centimetre beaker, then reweigh the weighing bottle to accurately determine the amount of solid added. Add any other necessary reagent, such as dilute acid then add about 50 cubic centimetres of de-ionised water, and stir the mixture until the soolid has completely dissolved It's bad practice to tip the solid directly into a volumetric flask - some solids are very slow to dissolve at room temperature. In such cases, gently warm the beaker carefully stirring the contents from time to time until the solid dissolves. Do not allow the mixture to boil, in case some drops of liquid splash out. Once a clear solution has been formed, remove it from the heat and allow it to cool. When the solution has cooled, first carefully wash the clock glass and the stirrer rod with de-ionised water. The remaining procedure is the same for solutions of solids, like the copper salt, which dissolve easily at room temperature.

Transfer the solution to a clean volumetric flask using a funnel to make sure that all the solution gets into the flask. Then rinse out the beaker with more water. Pour in de-ionised water until the level is about one centimetre below the calibration mark. Remove the funnel then add water dropwise using a wash-bottle, until the bottom of the meniscus is at the calibration level. Place the stopper in the flask, then thoroughly mix the solution by inverting the flask several times, keeping a finger firmly over the stopper. Notice that the flask has at all times remained at room temperature. Heating the flask will alter its calibrated volume so never heat a volumetric flask - it is a precision piece of equipment.

Solutions of standard reagents such as potassium dichromate or EDTA can be made up in a similar fashion. Alternatively, standard ampoules containing concentrated solutions of standard reagents can be purchased. There are several different types of ampoule in production, some made of glass and some made of plastic.

It is sometimes necessary to make up solutions of different known concentrations, starting from a standard stock solution. The easiest way to accurately dilute by a factor of 10 is to take 25 cubic centimetres of the stock solution in a pipette, then transfer it to a 250 cubic centimetre volumetric flask. Dilute the solution to the mark with deionised water. Then stopper the flask and thoroughly mix the contents. As the volume containing the solute has been increased 10 fold its concentration has been reduced 10 fold. If several different volumes need to be measured out. to give a range of concentrations, it may be easier to deliver the stock solution from a burette. Note that because 10 cubic centimetres can be measured out to higher accuracy than 1 cubic centimetre, normally a dilution of 100 fold is better done by diluting 10 cubic centimetres of stock solution to 1 litre, rather than one cubic centimetre to 100 cubic centimetres.

judulnya JENUH -,-
sungguh aku pngen pulang bngt :(
rasanya gak karuan :o
ibu , wiwit pngin pulang