Microscopy lab – slides, calibration, cell size and electron microscopes

What it shows

This virtual lab follows the standard microscopy practical. You prepare a temporary mount step by step, and every shortcut shows up in the image: no stain, a thick specimen, air bubbles or a floating coverslip. On the microscope you switch objectives, focus with the coarse and fine knobs without crashing the ×40 lens into the slide, and adjust the light. You calibrate the eyepiece graticule with a stage micrometer, measure cells and use magnification = image size ÷ actual size. Two further screens compare the resolution of light, transmission and scanning electron microscopes, and separate organelles by differential centrifugation.

How to use

Choose a Sample and press the buttons for each preparation step. On the stage, raise the stage with the coarse focus knob until the image appears, refine with the fine focus knob, then change objective. Turn on the Eyepiece graticule and use the Magnifier ×4 to count divisions. Calibrate with the Stage micrometer, then drag a cell under the + and Record its length. Use the tabs for Magnification, Light vs electron and Cell fractionation.

Parameters you can change

• Opening screen Microscope, Magnification, Light vs electron microscopes, Cell fractionation
• Sample Onion epidermis + iodine, Cheek cells + methylene blue, Elodea leaf, Pond water, Yeast, Cork, Sand, Blood (prepared slide), Stage micrometer
• Slide already made, on the stage and in focus
• Objective (when the slide is ready) ×4, ×10, ×40

Questions to explore

1. Why should you always start with the lowest-power objective?
2. Why must the eyepiece graticule be calibrated separately for each objective lens?
3. Why can a light microscope never show ribosomes, however much you magnify the image?