A microscope gives you the ability to view objects (referred to as specimens) at a microscopic level. This means that you can view things several times smaller than you would be able to with the naked eye and that you can gain a new perspective on ‘macroscopic’ (visible) items and see their cell structure. This makes a great hobby for anyone with an interest in science, and even with a basic relatively cheap microscope it is possible to make scientific discoveries and findings. Microscopes also make a great gift, and are perfect for young children as a way to get them interested in science and the way things work and to let them feel like budding scientists.
However picking a microscope whether for yourself or for someone else can be tricky, and what you want to buy will very much depend on your interests and your intended use for the device. There is no point buying a highly expensive electron microscope for a child when they will likely not need such high levels of magnification nor be able to operate them making it a waste of money. At the same time though if you want to start serious scientific investigations of your own then you will need something more advanced than the kinds of microscope you might buy at a toy store.
Level of Magnification
The first and simplest thing to look out for is the level of magnification that your microscope is capable of. A good children’s microscope will magnify 40 times, while a relatively inexpensive commercial optic microscope will likely go up to around 200 or 400. For professionals an optic microscope can magnify up to a thousand times. On the packaging you should find this marked as ’40X’ or ‘200X’. This literally means ‘forty times’ and that means that you can see things forty times bigger than you would with your naked eye.
Monocular, Binocular or Trinocular
Another thing that varies between microscopes is the number of eye pieces and the number of objectives. For those not up to speed with their microscope jargon, this refers to the lens that you look through and the lens that is closest to the specimen respectively. In terms of eye pieces it is possible to get microscopes with just one, two or three lenses respectively (actually each is made of several thinner lenses) and this is what is meant by a monocular, binocular or trinocular microscope. A monocular microscope is simple and allows you to look straight down the microscope tube to see the specimen underneath.
In the case of a binocular microscope there are two different types which are addressed below.
Single Lens Array
A single lens array is a binocular microscope with just one objective. This means that you look through the two eyepieces but each shows the same image. This merely allows for a larger image and means you do not have to close one eye which some people will find easier.
With a stereo microscope however there are two objectives positioned slightly differently at the bottom of the microscope (normally these can be rotated to change the view). This then means that you can get two angles of the same image by looking through a stereo microscope and that in turn can give you a three dimensional view of the specimen and provides depth perception.
In the case of a trinocular microscope you will then have a type of binocular microscope but with an extra eyepiece. This third eyepiece can have many benefits for instance it might allow a second person to look through the scope at the specimen. This is particularly useful for teaching and allows for teachers to look through the microscope and check the observations of students. In some cases it might allow for the user to use combinations of eye pieces in order to use their microscope as a stereo microscope or for a single lens array. Finally, the third eyepiece can also be used in order to benefit from additional features, for instance the ability to film or take photos from that eyepiece.
Light (optic) Microscope or Electron Microscope
Another way that microscopes are categorised are as ‘optic’ microscopes or ‘electron’ microscopes. Here optic microscopes are the ones that most of us will use on a casual basis and the ones most of us think of. These work by bending light as it comes through the lenses in order to make the fine details clearer and larger. Electron microscopes however use – you guessed it – electrons which react to much smaller items than photons. Whereas light might pass through or around smaller particles, electrons will rebound allowing for a much higher resolution (electro magnets are used to bend the electrons as opposed to the lenses which would be used to bend the light).
While a professional optic microscope can go up to 1,000X then, an electron microscope can go up to 100 million times which makes it useful for those who have a very serious interest in microscopy or for particular scientific investigation. They are less practical for children or hobbyists however as the specimens need to be specially prepared, and then held in a vacuum as air can slow down the electrons. However for those who are interested, it is possible to buy commercial electron microscopes. There are also multiple types of electron microscopes, and even acoustic microscopes.
Microscopes come with a range of additional features. If you are buying for a child you might want to buy a microscope with slides, specimen and instructions and it is possible to buy whole microscopy ‘kits’. More useful for those with a more serious interest however is the ability of some microscopes to take photos of the specimen or to film videos of it. This can even in some cases be streamed live via webcam so that people across the globe can see your results.