1. Microscopy Lab 3

2. Microscopy  Microscopes are used to view things that are too small to see without help. Dissecting microscope – view entire 3-D objects under low power. Compound light microscope – examine very small or thinly sliced objects under higher magnification.

3. Microscopy  Stains that bind to cellular structures are used to help increase the contrast and allow you to see the structures more clearly.

4. Using the Microscopes  Always use 2 hands to handle the scopes!  Be VERY CAREFUL when moving the microscopes.  Never remove any part of the microscope.

5. Using the Microscopes  ALWAYS adjust the nosepiece so that the LOWEST OBJECTIVE LENS is in place when removing a slide and when putting the microscope away!  NEVER, EVER use the COARSE FOCUS when you are working with high power!

6. Using the Microscopes  Always start with the lowest power lens – this gives you the widest field of view.  Find what you are looking for, CENTER and FOCUS as well as you can.  Then, change to the next objective lens.  Return to low power before removing the slide.

7. Rules  Lowest power objective lens in position at beginning and end.  Use only lens paper for cleaning lenses.  Do not tilt the microscope when you are using a wet mount.  Keep stage clean & dry.  DO NOT REMOVE PARTS!!!!  Turn light all the way down, then turn off before unplugging.  Replace cover when finished.  Report any problems.

8. Total Magnification  Compound Light Microscopes have 2 magnifying lenses. Objective lens – 4X, 10X, 20X, 40X Ocular lens (in the eyepiece) – 10X  Total magnification – multiply the objective lens (4, 10, 20, or 40) by the ocular lens (10).

9. Field of View  Field of view – the circular area that is visible when you look into the microscope. Measure the diameter, estimate lengths of objects that take up part of the field of view.  Depth of field – play with the focus while viewing the slide with colored threads.