Microscope Notes • The proper use of microscopes is important in your study of biology. • In the class you will find two different types of microscopes, a compound (high power) microscope and a dissection or stereo (low power microscope) Low power dissection microscope High power compound microscope
Microscope Parts High power microscopes have two lenses which provide the magnification. The first lens is located in the eyepiece and is 10X. The second lens is found on the revolving nosepiece and contains a 4X, 10X, or 40X objective lens. Total magnification is equal to the eyepiece x the objective lens selected.
Microscope Use • To use the microscope place a glass slide on the stage of the microscope, and turn the revolving nosepiece until the low power (4X) objective is in line with the eyepiece. • Use the coarse adjusting knob to turn the objective lens close to the stage. • Slowly move the coarse adjusting know until the specimen becomes focused. • Once your specimen is found on low power you can move the objective to 10X for more magnification, and then 40X.
Microscope Use • When your objective lens is on high power you only use the fine adjusting knob to focus. • Stage clips may or may not be used to hold your slide on the stage. • The diaphragm allows you to adjust the light allowed onto the stage.
Microscope Care *When done using a microscope move the objective lens to low power and place the cover over the microscope. • If you move a microscope use both hands and be careful. • Make sure to unplug your microscope when done. • Use lens paper to clean off dust from a slide of microscope lens.
Preparing Slides • Usually a specimen is placed on a glass slide, and sometimes a cover slip is placed over the specimen. • Rarely would you ever put a specimen directly on the stage of a microscope. • A wet mount involves placing a specimen on a slide, adding a drop of liquid, and then using a cover slip over the top.
Using the Microscope to Measure • Microscopes allow you to view things too small to be seen with the naked eye. • Using microscopes you can observe, measure, and study small structures and organisms. • To measure with a microscope you need to use a ruler to find the (mm) of your field of view on low power. Field of view
Measuring with a Microscope • When you know the diameter of your field of view on low power you convert these millimeters to micrometers. To do this you move the decimal three places to the right. There are 1000 micrometers in 1 millimeter. • Ex. 4 mm = 4000 micrometers • To find your field of view on medium power you take your low power field of view and divide it by 2.8. • To find your field of view on high power you take your medium power diameter and divide by 4 • In my example : 4000/2.8 = 1428 micrometers on medium • 1428/4 = 357 micrometers on high power
Measuring with a Microscope • To measure with a microscope you “estimate” based upon knowing your field of view. • What is the length of the specimen shown in the field of view to the right? Field of view = 500 micrometers
Measuring Practice Field of view : 500 micrometers Field of view : 1000 micrometers Diameter of specimen = ______ Width of specimen = ______ Length of specimen = _____ Area of specimen = ______