Minggu, 23 Oktober 2011



How to Use Your Compound Microscope

  • Set your microscope on a tabletop or other flat, sturdy surface where you will have plenty of room to work. Plug the microscope's power cord into an outlet. (Note: some compound microscopes don't use electric lighting, but have a mirror to focus natural light instead.)
  • Switch on your microscope's light source and then adjust the diaphragm to the largest hole diameter, allowing the greatest amount of light through. If you have an iris diaphragm, slide the lever till the most light comes through. See the diagram below for help locating these parts.
  • Rotate the nosepiece to the lowest-power objective (usually 4x for 40x magnification). It is easiest to scan a slide at a low setting, since you have a wider field of view at low power.
  • Place a microscope slide on the stage, either under the stage clips or clipped onto the meckanical stage if your microscope has one. A prepared slide works best when you do this for the first time. (If you do not have a prepared slide, place a strand of colored yarn or thread on a blank slide and place a coverslip  over it.) Move the slide until the specimen is under the objective lens.
  • Adjust the large coarse focus knob until the specimen is in focus. Slowly move the slide to center the specimen under the lens, if necessary. Do this by nudging it gently with your fingers or by turning the slide control knobs if you have a mechanical stage.
  • Adjust the small fine focus knob until the specimen is clearly in focus. Then adjust the diaphragm to get the best lighting. Start with the most light and gradually lessen it until the specimen image has clear, sharp contrast.
  • Scan the slide (right to left and top to bottom) at low power to get an overview of the specimen. Then center the part of the specimen you want to view at higher power.
  • Rotate the nosepiece to the 10x objective for 100x magnification. Refocus and view your specimen carefully. Adjust the lighting again until the image is most clear (you will need more light for higher power). Repeat with the 40x objective for 400x magnification, which will enable you to see all of the specimen detail that's necessary for high school biology lab work.
  • Optional: If your microscope has a 100x oil-immersion lens, you'll need to put 1-2 drops of immer oil over the slide coverslip (the piece of glass over the middle of the slide) before viewing it at highest power. Move the 100x objective lens into position, and then slowly move the stage up until the lens makes contact with the oil. Continue focusing with the coarse focus knob until the color or blurred outline of the specimen appears. Finish focusing with the fine focus knob. With the 100x lens, you will be able to see additional cell detail, but you will need to take extra care with focus and contrast for a clear image. When you are done using the slide, clean the oil off of the slide and the lens with lens cleaning paper and solution.

Diagram of Microscope Parts

Minggu, 09 Oktober 2011


By. Muhammad Ali Efendi, S.Si M.Si

The compound microscope uses lenses and light to enlarge the image and is also called an optical or light microscope (vs./ an electron microscope)The simplest optical microscope is the magnifying glass and is good to about ten times (10X) magnification.  The compound microscope has two systems of lenses for greater magnification, 1) the ocular, or eyepiece lens that one looks into and 2) the objective lens, or the lens closest to the object.  Before purchasing or using a microscope, it is important to know the functions of each part.   

Eyepiece Lens:  the lens at the top that you look through.  They are usually 10X or 15X power. 
Tube:  Connects the eyepiece to the objective lenses
Arm:  Supports the tube and connects it to the base
Base:  The bottom of the microscope, used for support
Illuminator:  A steady light source (110 volts) used in place of a mirror.  If your microscope has a mirror, it is used to reflect light from an external light source up through the bottom of the stage.
Stage:  The flat platform where you place your slides.  Stage clips hold the slides in place.  If your microscope has a mechanical stage, you will be able to move the slide around by turning two knobs.  One moves it left and right, the other moves it up and down.
Revolving Nosepiece or Turret:  This is the part that holds two or more objective lenses and can be rotated to easily change power.
Objective Lenses:  Usually you will find 3 or 4 objective lenses on a microscope.  They almost always consist of 4X, 10X, 40X and 100X powers.  When coupled with a 10X (most common) eyepiece lens, we get total magnifications of 40X (4X times 10X), 100X , 400X and 1000X.  To have good resolution at 1000X, you will need a relatively sophisticated microscope with an Abbe condenser.  The shortest lens is the lowest power, the longest one is the lens with the greatest power.  Lenses are color coded and if built to DIN standards are interchangeable between microscopes.  The high power objective lenses are retractable (i.e. 40XR).  This means that if they hit a slide, the end of the lens will push in (spring loaded) thereby protecting the lens and the slide.  All quality microscopes have achromatic, parcentered, parfocal lenses.
Rack Stop:  This is an adjustment that determines how close the objective lens can get to the slide.  It is set at the factory and keeps students from cranking the high power objective lens down into the slide and breaking things.  You would only need to adjust this if you were using very thin slides and you weren't able to focus on the specimen at high power. (Tip: If you are using thin slides and can't focus, rather than adjust the rack stop, place a clear glass slide under the original slide to raise it a bit higher)
Condenser Lens:  The purpose of the condenser lens is to focus the light onto the specimen.  Condenser lenses are most useful at the highest powers (400X and above).  Microscopes with in stage condenser lenses render a sharper image than those with no lens (at 400X).  If your microscope has a maximum power of 400X, you will get the maximum benefit by using a condenser lenses rated at 0.65 NA or greater.  0.65 NA condenser lenses may be mounted in the stage and work quite well.  A big advantage to a stage mounted lens is that there is one less focusing item to deal with.  If you go to 1000X then you should have a focusable condenser lens with an N.A. of 1.25 or greater.  Most 1000X microscopes use 1.25 Abbe condenser lens systems.  The Abbe condenser lens can be moved up and down.  It is set very close to the slide at 1000X and moved further away at the lower powers.  
Diaphragm or Iris:  Many microscopes have a rotating disk under the stage.  This diaphragm has different sized holes and is used to vary the intensity and size of the cone of light that is projected upward into the slide.  There is no set rule regarding which setting to use for a particular power.   Rather, the setting is a function of the transparency of the specimen, the degree of contrast you desire and the particular objective lens in use.
How to Focus Your Microscope:  The proper way to focus a microscope is to start with the lowest power objective lens first and while looking from the side, crank the lens down as close to the specimen as possible without touching it.  Now, look through the eyepiece lens and focus upward only until the image is sharp.  If you can't get it in focus, repeat the process again.   Once the image is sharp with the low power lens, you should be able to simply click in the next power lens and do minor adjustments with the focus knob.  If your microscope has a fine focus adjustment, turning it a bit should be all that's necessary.   Continue with subsequent objective lenses and fine focus each time.


Oleh. Muhammad Ali Efendi, S.Si, M.Si

Biologi merupakan ilmu dasar dari semua ilmu yang ada. Untuk mempelajari biologi, maka yang harus dilakukan diantaranya adalah:
A. Peka terhadap fenomena lingkungan
     Pada dasarnya yang dipelajari di dalam biologi adalah segala sesuatu yang ada pada diri kita dan sekitar kita. Diri kita dan segala sesuatu yang ada disekitar kita (lingkungan) merupakan sumber dari ilmu biologi. Kita harus peka terhadap fenomena lingkungan yang terjadi dan harus memiliki rasa keingintahuan yang tinggi. Kenapa muncul jerawat? Bagaimana kok bisa ada semangka tanpa biji? Kenapa kok ada variasi atau keanekaragaman pada makhluk hidup dan sebagainya.
B. Suka Membaca
     Setelah peka terhadap fenomena lingkungan, maka untuk sukses dalam mempelajari biologi dibutuhkan kesukaan membaca buku. Dengan membaca buku maka kita bisa memperluas pengetahuan dan kita bisa membuat suatu tali sambung antara fenomena lingkungan dengan teori yang sudah ada di buku.
C.Komunikasi dengan ahli
     Untuk mempertajam pengetahuan yang sudah kita peroleh, maka kita perlu untuk berkomunikasi dengan ahli. Misalnya dengan ahli virus, ahli penyakit, ahli tumbuhan dan sebagainya.
D. Perluas ilmu dengan internet
    Internet merupakan salah satu "buku terluas" yang bisa kita akses tanpa ada batas waktu dan ruang. kuasai ilmu dengan meningkatkan kemampuan dalam mengakses internet. Selain itu dengan internet kita bisa berkorespondensi dengan ahli biologi yang tidak terbatas. Sehingga pengetahuan kita semakin luas


SMPN 3 Peterongan merupakan salah satu instansi pendidikan yang mendapatkan amanah dari kementerian pendidikan nasional sebagai salah satu Rintisan Sekolah Bertaraf Internasional (RSBI). Untuk memujudkan amanah tersebut, maka semua komponen yang ada di dalamnya harus meningkatkan profesionalisme baik secara personal maupun secara kelompok. Secara personal, diantaranya dengan cara meningkatkan kinerja, memperluas pengetahuan sekaligus kemampuan dalam berbahasa Inggris dan penguasaan ilmu dan teknologi. Secara kelompok, terutama tenaga pendidik dalam hal ini adalah guru membentuk Musyawarah Guru Mata Pelajaran (MGMP). Di SMPN 3 Peterongan telah terbentuk MGMP tingkat sekolah (MGMPS). salah satu diantaranya adalah MGMPS Mata pelajaran Biologi. Di dalam forum MGMPS dibicarakan mengenai permasalahan dalam kegiatan belajar mengajar. yang diharapkan nantinya proses kegiatan belajar mengajar yang ada di SMPN 3 Peterongan bisa meningkat kualitasnya dan menghasilkan out put yang berkualitas dan dapat bersaing. Dalam rangkan untuk meningkatkan kualitas dan put put yang dapat bersaing, maka MGMPS mata pelajaran Biologi mendesain blog yang bisa diakses oleh peserta didik yang tidak dibatasi oleh ruang dan waktu. Dan akhirnya dilaunching blog mata pelajaran biologi dengan nama BIOLOGY SAINS RASTA dengan alamat http://biologysainsrasta.blogspot.com