Lab 1 Microscope

resolution

microscopes allow you to see fine detail as well.  Resolution is the ability to distinguish two objects that are close together as being two separate objects, rather than just one

magnification

use lenses to magnify the image of an object, but its more than just making things appear larger.

contrast

arises when different parts of an object absorb or transmit different amounts of light. Some parts then appear darker or lighter than others do.

to enhance contrast use

staining

table of the 3 different techniques

microscopes are good for (range)

of a tenth of a micrometer to a few millimeters.

eyepieces

The right eyepiece has a pointer that aids in the location of objects. The eyepieces have a special focusing (diopter) ring that allows you to precisely adjust the sharpness of the image for each of your eyes.

nosepiece has ___ objective lenses

4

total magnification of the microscope is the product of the eyepiece and objective lens magnifications.

With the lowest power objective in place, the microscope magnifies the image of an object 40 times (i.e., eyepiece 10X multiplied by the objective 4X). With the 100X objective in place the total magnification is 1000X.

mechanical stage

has a caliper that holds a slide in place. Once on stage, a slide is moved with the stage controls. The lower knob moves the slide left and right the upper knob moves the slide towards or away from you

focus knob

There are two focusing knobs that are used to sharpen the image. The outer ring is for coarse focusing and should be used only with the 4X and 10X objectives. The coarse focus knob moves the stage up or down quite a distance to permit focusing; if this knob is used with the 40X or 100X objectives it is possible to hit a slide with those objectives and ruin the slide. So, when using the higher magnification objectives use only the inner fine focus knob. The fine focus moves the stage vertically only a small distance.

Diaphragm

The condenser contains an iris diaphragm that can be opened to permit more light to illuminate the slide. When using the higher magnification objectives, the open diaphragm allows sufficient light to see objects clearly.

microscope

A stage micrometer is a

special slide that has a very tiny (1 mm) ruler inscribed on it as shown below (but much smaller and usually without numbers).

What is the relationship between total magnification and the apparent width of the pointer?

as total magnification increases, the apparent width of the pointer decreases