A microscope is one of the most precise tools in a science laboratory. By using it correctly, the microscopic world opens up before us.
Basic Knowledge
Procedure for using a microscope:
① Place it in a level location without direct sunlight that is bright
② Attach the eyepiece and then the objective lens (dust may enter if the order is reversed)
③ Set the objective lens to low magnification
④ Use the mirror (or light source) to brighten the field of view
⑤ Set the slide on the stage
⑥ While looking from the side, move the objective lens closer to the slide
⑦ While looking through the eyepiece, move it in the direction that takes it farther away to focus
A slide is prepared by placing a sample and water on a glass slide and gently placing a cover glass at an angle with tweezers so that air bubbles do not enter.
Stage (stage)（The platform on which the slide is placed）
Revolver (revolver)（The rotating part used to switch objective lenses）
Adjustment knobs (coarse・fine)（Knobs for focusing. The coarse knob is for rough adjustment and the fine knob for precise adjustment）
Diaphragm (diaphragm)（A device that adjusts the brightness of the field of view）
Mirror（A mirror that brings in outside light. A plane mirror and a concave mirror are on opposite sides）
Slide (preparation)（An observation specimen consisting of a sample, water, and a cover glass）
Further Study (Background・Significance)
The image seen through a microscope appears upside down and reversed left to right. If you move the slide in the opposite direction from the direction in which you want the image to move, the image will move in the desired direction.
The brightness of the field of view is adjusted with the diaphragm and mirror. At low magnification, the field is often too bright, so close the diaphragm; at high magnification, it becomes dark, so use a concave mirror (which gathers light).
The reason for placing the cover glass at an angle is to prevent air bubbles from entering. Bubbles appear as circles with dark edges and interfere with the field of view. Another useful technique is to drop water beside the sample with a dropper and spread it by capillary action.
Microscopes greatly advanced biology after Antonie van Leeuwenhoek discovered microorganisms in the 17th century. Modern electron microscopes can observe even the structures of viruses at the nanometer level (one-billionth of a meter).
- Order of attachment: eyepiece → objective lens
- Focus by “moving closer, then farther away”
- The microscope image is reversed vertically and horizontally
- Move the slide in the opposite direction from the direction you want to move the image
- Observe from low magnification to high magnification
- Place the cover glass gently at an angle (to prevent bubbles)
- Never expose the microscope to direct sunlight
Points to Note (Easily Confused)
① Focus by moving closer, then farther away. Otherwise, the objective lens may collide with the slide. ② Attach the lenses in the order eyepiece → objective lens, and remove them in the reverse order. ③ Do not use the mirror to reflect sunlight directly (it can damage your eyes). ④ As magnification increases, the field of view becomes narrower and darker, so the brightness must be adjusted with the diaphragm and mirror.
Practice
- If an object appears in the upper right of the microscope image, in which direction should the slide be moved to bring it toward the center?
- Briefly state the correct procedure for focusing.
- Why should the cover glass be placed at an angle when covering a slide?