Uses Of Dissecting Microscopes In School Laboratories

Dissecting microscopes are often used in school laboratories because these contraptions help students in their biological studies. Here are some examples of activities that the students are engaged in, thanks to dissecting microscopes.

1. Finding Bacteria in Yogurt
Now, that doesn’t mean that you should not eat yogurt anymore. Truthfully speaking, there is bacteria in practically everything we eat. We just don’t see it with our naked eyes. However, once armed with the dissecting microscope, the bacteria becomes clear. In this activity, the students need plain yogurt, distilled water and dropper. It is customary that they clean the slides and make sure that there is no dust. Then put a small portion of the yogurt on the slide and add a drop of water. The coverslip is placed on top.

The bacteria is often found in the section where the yogurt is quite thin. For a better view, switch the dissecting microscope into 400X optical lens.

2. Examining Blood
To the naked eye, human blood is a plain red liquid. But when viewed using the dissecting microscope, one will notice that blood has four elements. These are plasma, white blood cells, red blood cells and platelets. The plasma is the liquid part and is colorless. It is the red blood cells that give the blood the red color we all know. White blood cells are dispersed in the red blood cells. These prevent infection. Finally, the platelets are the fragments of red blood cells and they are responsible for the clotting of the wounds.

First and foremost, sterilize the pin that will be used by putting it through flame. Then poke your finger lightly and quickly. Squeeze the finger and make sure that there is a drop of blood on the slide. Cover it with the coverslip. Put band-aid as soon as possible on the finger in order to prevent infection.

By using 100X, focus on the blood. You will see hundreds of minute red blood cells that are circulating through what seems to be a stream. Red blood cells have no nucleus, therefore they cannot be divided. They are also produced by the spleen and the bone marrow.

The white blood cells are also visible. They are larger than the red blood cells. They also have nucleus. They are like an amoeba because their bodies can be contorted in whichever way they prefer. The platelets are very small. Person should clean the slide after observation. It is not sanitary to have the blood come in contact with someone else’s blood.

3. Examining Pond Weed
With the dissecting microscope, users can examine the chloroplasts within the plant cell. They can also observe how salt water affects the cell.

The materials needed for this activity are live pond weed, salt water and distilled water. Take the pond weed and break the leaf. The leaf must be placed on the dry slide. Add distilled water – just a drop. Cover it with the cover-slip. By using the dissecting microscope (100X-150X), examine the specimen. If the microscope has a diaphragm, keep this low and a regulated setting.

Notice that the cells have a patter. The organelles move inside the plant. By letting the right amount of light, you will notice that the green globs rotate and surround the cell’s outer edge. These are the chloroplasts. They get the light for the cells. When you expose the chloroplasts to light, they move rapidly because they get excited.

4. Observing Frog Blood
Frog blood is like that of human feelings. Why do you think that frogs are often dissected in biology? By examining the blood of frogs, we know what ours is like. Like that of human beings, the blood of frogs also has four components – red blood cells, white blood cells, platelets and plasma. The difference is that the red blood cells have nucleus, whereas with human beings, it is the white blood cells that contain it. The white blood cells of the frogs are similar to that of human beings and also have the same purpose. Try looking for platelets. If you cannot find any, do not fret. There is no platelet because frogs do not produce the fragment-like platelets that human beings do.

5. Slow Down Protozoan
Observing protozoa through dissecting microscope is entertaining but they move so fast that it is hard to see them. You can see them but only for a split second. If you’re lucky, maybe even two. There are chemicals that can be used to slow them down. You will be needing water specimen from swamp, pond, puddle or stream, cotton swab and eye dropper.

Place a drop of the sample water with the protozoa on the microscope slide. Pull cotton fibers from the cotton ball or cotton swab and then shred these using your fingers. Put these fibers in the water and put the cover-slip. Trap the air bubbles. Observe this under the microscope and you will notice that you were able to trap the protozoa and they do not move as fast as they normally do.