Microscope Basics

Ocular lens (Eyepiece) Body Tube Nosepiece Arm Objectives Stage Stage Clips Coarse Adjustment Diaphragm Fine Adjustment Light Always carry a microscope with one hand holding the arm and one hand under the base. Base

What’s my power (total magnification)? To calculate the power of magnification (total magnification of a specimen), multiply the power of magnification of the ocular lens by the power of magnification of the objective lens. What are the total magnifications for each of the objectives lenses we have on our microscopes? Complete the chart below for each objective lens Objective Lens (X) Ocular lens (X) Total Magnification (X) 4 10 40

Let’s give it a try ... 1. Carry a microscope with both hands. One hand at the arm and the other under the base 2. The microscope should always be stored with the low-power objective in position. If the microscope has not been stored that way, look from the side and rotate the revolving nosepiece until the low-power objective clicks into place.  

3. Look through the eyepiece (ocular) and adjust the diaphragm to obtain the maximum amount of light. 4. Under low-power, place the prepared slide on the stage. Center the specimen over the hole in the stage and use the stage clips to secure it in place. 5. Look through the eyepiece. Slowly turn the 2 coarse adjustment knob until the specimen is in focus.

6. Use the fine adjustment knob to sharpen the focus. 7. Once the specimen is in focus under low-power, carefully rotate the revolving nosepiece to the medium-power objective. Be sure to look at the side of the objective as you rotate the nosepiece to ensure that the objective lens does not strike the surface of the slide. Adjust the focus using ONLY the fine adjustment knob.

9. To view the specimen under the high-power objective, carefully rotate the nosepiece until the high-power objective clicks into position. Again, be sure to look at the side of the objective to ensure that the objective does not strike the surface of the slide. 10. Adjust the focus using ONLY the fine adjustment knob. 11. Once viewing the slide is complete, carefully rotate the nosepiece until the low-power objective is in position.

12. Turn the light source off. Unplug the microscope and return it to its proper location.

Explore microscope slides of common things…… Work in groups of 3. Check your microscope. Obtain a slide of common things from your teacher and make observations. Give all 3 group members have an opportunity to view. Once finished, you can switch by returning your slide for another one.

Scientific Drawings….. Use unlined, blank paper. Use a sharp pencil with an eraser (pencil ONLY). Ensure that the size of the drawing is the same as what you see in the field of view. Draw only what you see! Write the magnification that the specimen was viewed under on the bottom right side of the circle. Provide a title – it should be underlined and centered above the diagram.

Label the diagram using lower-case (small) letters. Label to the right side of the drawing using straight, horizontal lines. The lines should be parallel and never cross. Use a RULER! Align the labels in an imaginary column. Do not shade, colour, or use lined strokes, but instead use stippling (a series of small dots) to show contrast and darker areas. Use double lines to show thick parts in your drawing.

Onion cell 120X

What is wrong with this Scientific Drawing?

Practicing Scientific Drawings…… Obtain a microslide viewer. Obtain a slide strip from the teacher. Observe the slide indicated by the teacher. Create a proper scientific drawing of the specimen viewed. Be sure to follow all the guidelines provided in your worksheet. Once finished, hand it in!!!!!

You do not need to use the stage clips when viewing wet-mount slides! Preparing a Wet Mount: 1 – Get a clean slide and coverslip from your teacher. 2 – Place ONE drop of water in the middle of the slide. Don’t use too much or the water will run off the edge and make a mess! 3 – Place the edge of the cover slip on one side of the water drop. 4 - Slowly lower the cover slip on top of the drop. Cover Slip Lower slowly You do not need to use the stage clips when viewing wet-mount slides! 5 – Ensure there are no air bubbles interfering with the specimen. 6 - View it first under low-power. Once you see the image, you can rotate the nosepiece to view the slide with the different objectives.