Microscopes: Discovering the hidden world
In much the same way telescopes helped us expand our knowledge of the universe by letting us see things that are beyond our view due to their vast distances, the close relative of the telescope – the microscope – has had even more impact on our lives by revealing the world of the extremely small.
This short guide is an introduction to the basic types of microscopes, what they’re used for and how recent tech advances have made microscopes even easier to use while enhancing their abilities.
Quick Gift Suggestion.
Here’s a gift suggestion for the keen young scientists who’d like to explore inner space.
Includes a quality Celestron microscope for beginners a range of accessories. Includes prepared samples and blank slides to create your own.
Microscopes were a result of the invention of clear, ground glass lenses to help eyesight which occurred sometime in the 13th century. History doesn’t record which optician discovered holding lenses at a certain distance would let you magnify things close to you. We know these early devices as magnifying glasses.
By the early 17th century as optics improved and the invention of the compound microscopes, major discoveries in the field of biology were made. A compound microscope uses two or more lenses to further magnify images. Famous scientists such as Robert Hooke and Antonie van Leeuwenhoek opened up the hidden world beyond the reach of our eyes. Early discoveries including blood cells and microorganisms that revolutionised the understanding of life are today easily visible in modern microscopes.
Drawing of a flea by Robert Hooke, 1665. Image via State Library NSW
Types of microscopes – what do you want to look at?
Broadly speaking there’s two types of optical microscopes. Which one is right for you depends on what you want to look at.
A biological microscope is what most people picture when they think of microscopes. It’s made up of an eyepiece and another lens close to the object you wish to observe. Often, they have a “turret” on the front of the microscope that lets you change the magnification by a simple turn that selects another lens. Biological microscopes offer the highest magnification of optical microscopes and are ideal for looking at biological materials from both animals and plants. This includes specimens from large animals – human beings included – right down to animals that can’t be seen with just our eyes. Magnification can go up to 1000x but like telescopes, the highest magnification available mightn’t give you the clearest views. Often a lower magnification enables you to see more of your specimen at the same time giving sharper views.
A Celestron Biological Microscope
You’ll be amazed at the range of tiny creatures from a pool of water from your garden that you’ll see with even a low-cost biological microscope.
View of plankton under a microscope
A sample of onion skin viewed under a microscope
Samples for viewing on biological microscopes are often prepared by sandwiching them between two glass slides. To highlight details, light for viewing the sample is shone from under the “stage” where the sample is held. This can be a small electric light or for simplicity, reflected up by a mirror at a 45-degree angle.
Blank slides for preparing your own specimens are readily available along with prepared slides with sample specimens to start experimenting right away. Various stains are used with many biological specimens to highlight details.
You focus a biological microscope by slowing moving the stage where the specimen is held with focus knobs on the side of the body.
Quick note – Biological microscopes are so popular they’re often referred to as compound microscopes, but stereo and handheld microscopes also use a series of lenses with one close to the specimen as well.
Optical compound microscopes haven’t really changed that much in basic design over the last couple of hundred years. What many people don’t realise is that advances in optical design via computer, mass production and the availability of quality optical glass means a low-cost microscope can often have the same image quality as a far more expensive instrument from a few decades ago.
Biological microscopes are perfect for examining details in objects that are too small to even be seen with just your eyes. For viewing the finer details of larger objects, you would use a stereo microscope.
Examples could include examining minerals, electrical circuits, fine mechanical devices like watches or even larger biological specimens such as plants.
A Saxon stereo microscope
The two eyepieces in a true stereo microscope have separate optical barrels. To view anything in 3-D you need to view it through both eyes.
Magnification for stereo microscopes is much lower than compound microscopes, usually up to about 300x. They’re focused by moving the body of the microscope up and down, rather than the stage where the samples are held. In other words, what you’re looking at stays in the same position. As the larger objects typically viewed with a stereo microscope aren’t transparent, the light source comes from on top of the sample, not from under the microscope. It’s also possible to manipulate or even work on what you’re looking at as it doesn’t need to be sandwiched between two glass slides as you would need to do with a biological microscope.
Watch mechanism at 40x magnification (Image by R. Neumeyer)
Technology and microscopes
Like telescopes, capturing images seen through microscopes has undergone major changes in recent years. BINTEL sells two types of digital microscopes, fully digital and combination.
A fully digital microscope replaces the eyepiece with a digital camera that either displays the specimen on an integrated screen or sends the image out via HDMI or USB. Many of these types of microscopes are ideal for showing specimens to groups of people including students. They often allow images or even videos to be saved on a memory card or a computer.
Recently viewed in our BINTEL store was an amazing range of plankton in a water sample scooped up from Sydney Harbour by Australian Maritime Museum staff.
Despite their complexity digital microscopes are still affordable for home and casual use.
A hybrid digital microscope lets you attach a separate digital camera to capture what’s being viewed through the microscope’s eyepiece. Some microscopes also have a USB camera included that can be swapped out with the eyepiece.
A Saxon stereo microscope with a USB camera port behind the two eyepieces
These are small microscopes designed to hold up against an object to examine it closely, check out insects or look at plankton in water. They have a built-in light that shines down on what you’re looking at. Low-cost models like the Kenko Pocket Microscope have small eyepiece that you look into, while more advance handheld microscopes such as the Celestron MicroDirect can connect directly to a large screen.
Celestron MicroDirect microscope being used to examine insects
View of fabric through a Kenko handheld microscope
How to select what’s the best microscope for you.
If you ‘ve never used a microscope before one of our complete bundles from Celestron would be an ideal choice. If you need to present to a group of people, then an LCD microscope might be a good option. Drop us a message at BINTEL and we’re more than happy to help you select one that’s right for you.
Do you have any good books on microscopes?
Yes, we have some informative books on microscopes which make ideal gifts for both kids and adults.
Check the BINTEL microscope accessory section here for more information
Finally – What’s an electron microscope?
Electron microscopes use accelerated streams of electrons to illuminate objects and view them in magnifications beyond what can be achieved in visible light. They use shaped magnetic beams in much way the same glass lenses in conventional microscopes bend light. As you might imagine, they’re complex and expensive machines and no, we don’t sell them at BINTEL. 🙂