Microscopes

Eyepiece Contains the ocular lens Nosepiece Holds the high and low-power objective lenses; can be rotated to change magnification. Objective Lenses Magnification ranges from 10X to 40X Stage Clips Holds the slide in place Stage Supports the slide being viewed Light Source Projects light upwards through the diaphragm, the specimen, and the lenses. Base Supports the microscope Diaphragm Regulates the amount of light on the specimen Fine Adjustment Knob Moves the stage slightly to sharpen the image. Coarse Adjustment Knob Moves the stage up and down for focusing. Arm Supports upper parts of the microscope, used to carry the microscope.

What’s my power? To calculate the power of magnification, multiply the power of the ocular lens by the power of the objective.

Fill in the table Our ocular lens has a magnification of 10X. What are the powers of magnification for each of the objectives we have on our microscopes? Fill in the table on your worksheet. Objective lensTotal Magnification 4X 10X 40X

Comparing Powers of Magnification We can see better details with higher the powers of magnification, but we cannot see as much of the image. Which of these images would be viewed at a higher power of magnification?

Handling The Microscope When you need to move the microscope from one place to another, use both hands! – One hand should be under the base and the other one on the arm. Do not touch the lens with your fingers. Use ONLY lens paper to clean the glass— tissue, TP, paper towels with scratch the lens!

Using the microscope Make sure the power is on the lowest magnification (4X). Place the slide on the stage and use the stage clips to hold it in place. Adjust the diaphragm—to let more or less light travel through.

Using the Microscope Use the coarse adjustment knob to move the stage and get the specimen in focus. – You can use the fine adjustment (very slightly) to sharpen the focus. Adjust the diaphragm as needed to change the amount of light if more or less contrast is needed.

Turn to the 10X lens and use ONLY the FINE adjustment to focus. If needed, you may change your magnification to high power (40X). – NEVER use the coarse adjustment knob on medium or high power objective lenses!!!!

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 knob 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.