Microscope Match Up

Isn't it wonderful how microscopes can introduce another part of the wonderful world of science to us? We can peak at the finest details of God's magnificent creations. We have had the pleasure of ordering microscopes for our family and our children were so excited to use them. But how do you choose a microscope anyway? Where can I purchase a microscope? Well, there are just as many suppliers as there are microscopes but there are mainly two kinds of microscopes that you can look at for your homeschool and those are compound microscopes and stereo or dissecting microscopes. What's the difference? Well, let's take a quick peek.

Compound microscopes have come a long way since the days of Galileo and are the most popular or common microscopes for students and for several reasons.

• high magnification usually up to 1000x of magnifying power


• able to view specimens at the cellular level which makes them great for biology and life science


• usual cost starts at $150 and up

Stereo or dissecting microscopes are less comprehensive microscopes as they have less complicated features compared to the compound microscopes.

• lower magnification usually between 60x up to 120x


• able to view whole objects such as rocks, leaves, and insects (from different lens angles) which makes it great for nature studies and dissected specimen views.


• cost can start at $150 and up

A small version of a stereo microscope would be a pocket microscope. This is what my younger children own and they absolutely love studying insects and other objects that they collect on their nature studies. It is very inexpensive (less than $15). It has a power magnification of 15x to 100x and is great for viewing insects, leaves, salt and sugar crystals, and single cell protozoa although it can not view bacteria or blood cells with this magnification. Can you see how they crowd around this thing in the pic? Even my 19 month old was trying to push in for a view. Can you see her little hand? Too Cute!



OK, so how do I know which will be best for our homeschool? Well, that depends on a few factors.

1. Use- What are you going to use the microscope for?


2. Magnification- What power of magnification are you needing in order to view certain specimens?


3. Price- What is your budget? You want to get the best quality scope for your money. And don't forget about that warranty.


4. Comfort-You want to get a microscope that will be comfortable for your children as not to strain or hurt their eyes. You would also want a sturdy microscope. Don't waste time and money on those little plastic deals which can't last very long.
   

Now, let's have a mini vocab lesson and review a few microscope terms that you may stumble across on some supplier sites.

Compound microscope- It's called that just for that reason. It has two lenses. One at each end of the eyepiece.

Eyepiece- First lens that you view from. Magnifies the the resolution (how close objects appear). Usual magnification power is that of 10x. The wider the eyepiece, the wider the field of view of your specimen. There are microscopes with two different forms of heads or eyepieces, monocular (one eye piece) and binocular (two eye pieces). If you are going to use your microscope often, the binocular would be the best choice. However, very young eyes may have trouble viewing through these. Their eyes may have difficulty viewing two images at the same time and delivering those images to their brains as one image. Younger eyes may tolerate the monocular microscope a little better. There are even some microscopes available that have digital cameras and video recording capabilities.

Objective lens- The second lens and most important lens in your microscope. This is the lens that determines the resolution (how close objects are seen). There are usually three objective lens on a microscope and each having a different magnification power. The higher the magnification of this lens, the more detailed view which you are able to have. Achromatic (color corrected) objective lens are the common types. They show the true color of the specimen. Another yet more expensive alternative is the semi-plan or plan objective lens. Those are mostly used in clinical lab settings. Most lens are DIN (Deutsche Industry Normen- a set of standards created by German lens manufacturers) compatible which ensures that it is able to be replaced with any other DIN lens if needed instead of purchasing an entire replacement microscope. You can check with the supplier for warranty details prior to purchasing.

Oil Immersion Objective lens- A fourth objective lens available on some models which allows greater cell magnification by applying a few drops of immersion oil onto the slide cover slip. The oil prevents light distortion for a sharper image. This lens is great for viewing bacteria and striations of skeletal muscle.

Focusing- Moves the stage to bring the specimen into a closer view. There are two kinds of focus. Coarse focus- lowers and raises the stage of the specimen for viewing and Fine focus which fine tunes the image. Some microscopes have coaxial knobs in which the coarse and fine focus are controlled by one knob instead of two separate knobs. A good microscope will usually have the two separate knobs.

Stage- the platform for placing your slide specimen

Diaphragm- Most compound microscope have an iris diaphragm. Mirrors are ok but a diaphragm is better. The diaphragm is a rotating disc which allows for higher image resolution by controlling how much light hits the specimen.

Magnification-magnifying power of the scope in which objects are viewed in greater detail. The total magnification of a microscope can be obtained by multiplying the magnification of the eyepiece by the magnification of the objective lens.

Illumination (lighting)- There are three different types of bulbs for microscopes.

• Tungsten (Incandescent): the most common yet hottest bulb and less bright


• Fluorescent: more expensive, white light and produces little heat


• Halogen: produces bright white light and usually comes with a dimmer. Found in the expensive models.

So now that we have taken a quick mini tour of the world of microscopes, you can take this little quiz. Ha! Seriously, there are some great suppliers that are availabe for purchasing your microscope. One supplier which I absolutely love is Homes Science Tools. There are microscope "how to" videos on their site also. A few other microscope sites are Microscope.com, Rainbow Resource, Tobin's Lab, Nature's Workshop Plus. There are also great Microscope books available like Usborne's The World of The Microscope and The Complete Book of The Microscope. I hope that this post has helped you match a microscope for homeschool needs. If you have more thoughts of wisdom to add that would assist others in their microscope match, please leave a comment. And if you would like to share a blog post about an experiment or other ways your homeschool has utilized a microscope, please include your blog linky in your comment.