The zoomable image shows the cross-section through the tongue of a rabbit. The muscle fibers are stained red-brown. The structures at the top of the image (bordering the white background) are the taste buds. The striations (light and dark bands) are not visible due to the lack of resolution.

The image shows a cross section through the stem of a pumpkin. Pumpkins belong to the dicotyledonous plants. The circular arrangement of the vascular tissue indicates this. Fifty five individual images were stitched together to make this zoomable image. The final size is about 100 megapixels (10000×10000 pixels). Happy exploring!

Use the horizontal slider to zoom into the image. On the left you can see a collapsed vein (the structure with the shape of a “2″), the oval structure on the right bottom is an artery. You can clearly see that the wall of the artery is substantially thicker. This is necessary to withstand the higher blood pressure.

The apical meristem is the quickly growing part of the roots and shoots of plants. It is an ideal place to observe many dividing cells. The zoom image shows two onion root tips. Try to find the different stages of mitosis, in which the chromosomes are then clearly visible. Compare the cell division stages of the onion with those in the lily: Mitosis stages of the Lily

Online Digital Microscope
This virtual microscope allows the user to choose from a variety of plant, animal and microbe specimens. It is not a comprehensive simulation of a microscope, but still useful for educational purposes because of the description of the different specimens.
I liked: The descriptions of the specimens were very complete (including staining information etc.). There are numerous specimens to look at and to explore.
I did not like: In order to switch to a higher magnification, it is necessary to click into a small rectangle. It is therefore possible to only magnify pre-selected areas.
Use it for: giving an overview of different staining techniques and for showing the differences in cell shapes.

Bob Ketcham’s Virtual Microscope
This interactive site is a true simulation of a microscope. The users even have to switch the micoscope “on” in order to see something. An instruction (with audio!) is included as well. This is a true instructional interactive site which allows students to experiment with the microscope. Here is the project homepage.
I liked: The instructional audio is great. It is a full simulation of the microscope. If the slide is not centered, you won’t be able to see anything. There is much attention to detail.
I did not like: There are only 4 specimens to choose from. For this reason there is not much for students to explore (the focus of the site is more on operation of the microscope).
Use it for: instructing students on how to use a compound microscope.

Kbears Virtual Microscope
The Kbears Virtual Microscope is a site for younger students (elementary school). It’s not a true microscope simulation, but rather a collection of 11 microscopic images.
I liked: Children-friendly design, short explanations of the specimens.
I did not like: low resolution of some images, no possibility to zoom in and to magnify.
Use it for: showing students different pictures of specimens (“What is this?” type of activity).

Virtual Petrological Microscope
This software simulates a petrological microscope. There are 7 rock samples to choose from. It is suitable for teaching students how to make measurements under the microscope.
I liked: It also allows users to switch to polarized light. It’s one of the rare non-biological “microscopes”.
I did not like: I could not figure out the function of the two circles at the bottom of the site. The documentation could be better.
Use it for: Showing students how to make measurements and magnification calculations.

Virtual Cell Staining Tool
Here the users can see the effect of different antibody-based (immunological) stains. Users can choose the different stain types and colors.
I liked: The different parts of a cell can be visualized very well.
I did not like: It does not say which cell it is. There are many different stains to choose from, but there is no visual difference for some of these stains.
Use it for: showing students how different cell organelles and structures look using fluorescent stains.

MicrobeHunter Virtual Microscope
Ha! And you thought I’ve forgotten! And because I’m fair, I’ll also critically evaluate my own virtual microscopy project.
I liked: The large images. There is plenty to explore. It’s also possible to seamlessly zoom into the specimens.
I did not like: No information concerning magnification is given. There is no reference point concerning magnification.
Use it for: Enjoyment and entertainment and to marvel about the beauty of nature! Why does science always have to be educational and “serious”?

The male pine cone (or flower) is responsible for forming pollen. These pollen grains are also visible in the image above. For a zoom-able image of a female pine cone, visit the following link: Virtual microscope: female pine cone (Pinus)

The image above shows Lumbricus terrestris, the earth worm, in cross section. The red part in the center is the digestive system. You can zoom into the image. The only adjustment done to the image was a color correction. The image was not sharpened.

This the the parachute of a dandelion seed. The seed is not shown, it is attached to the long extension on the right. The leaves of the plant are toothed. The name “dandelion” comes from the French “dent-de-lion” meaning “lion’s tooth”. The microscopic observation reveals that the leaves are not the only part of the plant that have teeth. The fine hair of the parachute also show a tooth-like appearance.

Quite noticeable is the chromatic aberration, which can be seen as a blueish fringe around some of the hair.

This is a darkfield image of a tick. Ticks are blood-sucking arthropods. They possess 8 legs and are not insects, but rather are related to the spiders. Ticks are known to transmit various diseases, such as Lyme’s disease and encephalitis.

For more information on the tick, read the following post: The Tick (Ixodidae).

This is a scan of maple leaf vascular tissue, done with a normal flat-bed scanner.

Method: Preparing the leaf was the difficult and time-consuming part. The leaf was boiled for several hours until the cells started to separate. I then carefully lifted the leaf out of the pot and placed it on a plate with water. The soft tissue was then removed with a stiff brush, trying not to damage the delicate veins. The veins were then rinsed in alcohol to remove the remaining chlorophyll, washed in water to remove the alcohol. The alcohol also shrinks the structures, but it will expand again when washed in water. The leaf skeleton was then, pressed and dried. Not all leaves work equally well! The leaves of some plant species are so stiff that the cells do not want to come off when boiled. Don’t waste your time on these leaves.

A confession: Because the stem of the leaves come off very easily, I had to scan it separately and then integrate it into the picture later using some photo editing. I could not scan the veins and the stem at the same time, because it then would not be flat on the scanner. You will also notice that some parts of the leaf are not in focus. This too is because the leaf was not completely flat on the scanner.

For teachers and parents: Boil some leaves with your students/children and let them prepare the leaf skeleton. Then observe the leaf skeleton under the stereo microscope.

For more information on the pine cone, have a look at the following post: Female Pine Cone (Pinus) The specimen size is approximately 20mm from left to right.

If you can not see anything, then you need to install a flash player. The image shows the cross section of the stem of the Aristolochia sipho plant. The image is an inverted (negative) image, and not a dark-field image. Why did I choose to invert the colors? The reason is surprisingly unscientific: it simply looks better… The diameter of the stem is about 6mm across. The annual rings are also visible.