Microscope – Cell Division Lab Report

The purpose of this experiment was to:

study the magnification, field of view, and depth of focus in a light microscope

study chromosome arrangement during cell division of onion

Part 1.

a.

Magnification is one of the most important parameters in microscopy. It is the ratio of an object's image size to its real size.

The field of view is the area in the circle of light which can be viewed through the ocular.

The depth of focus is the range of image plane position at which the image may be viewed without appearing out of focus for an object or specimen that does not move or change location during the viewing. This means that the depth of focus is how clearly the specimen or object appears to a human eye; it is the thickness of the specimen that can be seen in focus. The higher the magnification, the lower the depth of focus.

Experimental procedure

The field of view was studied using letter 'e' slide as a specimen.

The 'e' slide was placed on the stage and centered in the field of view.

The orientation of the letter on the slide was compared to the image appearing in the field of view

The similar comparison was done for moving the slide to the right.

The slide was observed with naked eye, 4x, 10x, and 40x objectives.

Experimental data and summary of the results

The image of 'e' was inverted under a microscope (it appeared upside down in the field of view). When specimen was moved to the right, the image moved to the left in the field of view. It was due to the construction of a microscope: one lens inverts the image, the others magnify the inverted image.

The drawings of the observed images are on the attached sheet.

b.

The magnification and depth of focus were studied using a slide of color threads as a specimen (blue, red and yellow)

Experimental procedure

The thread slide was centered on the stage; the focus was set [magnification 4x]

The focus was slightly adjusted up and down; the number of threads in focus at each time was noted.

The...