In this video, we're going to introduce microscopes. A microscope, as its name implies, is really just an optical scope used to visualize microscopically small objects, such as cells, for instance. The root 'micro' means small, and scopes are objects that we look through with our eyes. There are two main types of microscopes that are commonly used, which you all should know about, and we've got these two microscopes numbered down below, number 1 and number 2.
The first type of microscope that you all should know is the light microscope, which, as its name implies, uses light to magnify small objects and make them appear larger. The second type of microscope is the electron microscope, which is much more complex, advanced, and a much more powerful tool than the light microscope. That's because electron microscopes use electrons for an even higher magnification of small objects. Let's take a look at our example down below at the ranges of the human eye, light microscopes, and electron microscopes.
You can see here for perspective, humans are on the right-hand side and atoms on the far left-hand side. This indicates that the left-hand side represents things that are really small, and the right-hand side represents things that are much larger. As we move from left to right, things are getting larger. You'll notice here, at the bottom in green, we have the range of the human eye. Our eyes can visualize really large things, going much beyond the size of humans.
However, there is a cutoff, and the range of the human eye can only see things that are so small. To visualize most plant and animal cells and most bacteria and archaea, we need to use microscopes. In blue, we have the range of the light microscope, which is used to visualize most plant and animal cells and most bacteria and archaea. But, the light microscope also has a cutoff, and it’s not powerful enough to visualize viruses, for the most part.
If we want to visualize things that are even smaller, we need to use another type of microscope, defined as the electron microscope. The electron microscopes are much more powerful tools and can be used to visualize most plant and animal cells, most bacteria and archaea, viruses, molecules such as proteins and lipids, even smaller molecules such as water, and atoms themselves. Electron microscopes are very powerful and very expensive tools, whereas light microscopes are still helpful for magnifying lots of small cells but are not as powerful or expensive. Most of you, if you've taken a biology lab before, may have even used a light microscope yourself in the past.
The electron microscopes, as we'll learn more about in our next video, are much more expensive, and the chances that you would have used an electron microscope are very slim due to their high cost. You can see here that frog eggs are cells that we can visualize with our human eye. Some cells, we actually are able to visualize with our human eye. But note that most plant and animal cells and most bacteria and archaea are too small for us to see.
Here you can also see ants, which you might think of as being really small. But in perspective to things like atoms, ants are incredibly large. That's why they're towards the larger side here. One other major takeaway of this image is that most plant and animal cells, which we know from our previous lesson videos are eukaryotic cells, are significantly larger than most bacteria and archaea, which are prokaryotic cells. This concludes our introduction to microscopes, and we'll be able to talk a little bit more about electron microscopes in our next lesson video. So I'll see you all there.
