Tuesday, July 31, 2012

Stereo Microscope Parts

Below is an image of the HSZ6T-TBL trinocular stereo zoom microscope. Stereo zoom microscopes provide a zoom range of magnifications usually somewhere in the range of around 10x - 40x. The particular microscope shown below provides 6.7x - 45x without any added auxiliary lenses.

Stereo zoom microscope.

  • Trinocular port - The trinocular port is provided to attach a microscope camera or a digital SLR camera. A microscope camera is typically added to the trinocular port by attaching a c-mount adapter (a lens with threads on it) and then the microscope camera is threaded onto the c-mount adapter. Some microscopes have a c-mount adapter built into the trinocular port.
  • Eyepieces - Typically stereo microscopes utilize 10x eyepieces, although 15x and 20x are usually available. The eyepieces are where the user looks in order to view their magnified object.
  • Objective Lens / Auxiliary Lens - Total magnification in a stereo microscope comes from the combination of eyepiece magnification and objective lens magnification (and if in use, the auxiliary lens). For example, on this particular stereo microscope the objective lens has a range of .67 - 4.5, which when combined with 10x eyepieces provides magnification of 6.7x-45x. Auxiliary lenses can be used to increase the magnification or change the working distance.
  • Working Distance - The working distance is the amount of room required between the top of the object and the bottom of the objective lens in order for the image to be in focus. On the microscope shown about the working distance is 110mm. If you were trying to view a very large object under this microscope and could not maintain 110mm between the top of the object and the bottom of the objective lens, the item would not be able to be in focus.
  • Reflected Light - The reflected light shines down from above and illuminates the specimen. This light can be angled to cast light on different parts of the object being viewed.
  • Transmitted Light - Transmitted light shines up from beneath the stage and often is turned off when using the stereo microscope. Many items viewed under the stereo microscope do not allow light to pass through them, therefore some stereo microscope stands do not even provide a transmitted light.
  • Rheostat Control - The rheostat control allows the light to be adjusted for brightness.
  • Stage Plate - Typically a stereo microscope is provided with two stage plates - a glass stage plate and a black/white reversible contrast plate.
  • Track Stand - A track stand has a rigid arm and allows for adjustment of the head up and down.
  • Coarse Focus - The focusing knob allows the microscope to be adjusted for the proper distance between the specimen and the objective lenses, providing a crisp, clear image. If very high magnification is being used, a fine focus knob is also usually desirable.
  • Zoom Knob - The stereo zoom knob increases or decreases magnification depending on which way it is adjusted. Some stereo microscopes have click-stops on the zoom knob. A click stop allows the user to know exactly what magnification they are at. This becomes especially helpful when using a reticle to make precise measurements.

Friday, July 27, 2012

Veterinary Microscopes

Veterinary microscopes are used for diagnostic methods similar to standard human laboratory medicine. Diagnosis becomes a bit more complicated because patients are unable to communicate, and many of the animals respond differently to treatment.

Swift M10LB veterinary microscope.

A high power biological veterinary microscope is useful for examining bodily fluids and skin or hair samples. These specimens can often indicate parasitic infections, allergies, neoplastic disease or microbial infections. More time intensive veterinary microscope lab work is generally required for pathology, microbiology, molecular biology, hematology and immunology-based tests. The most common veterinary microscopy techniques utilized include brightfield, darkfield, phase contrast and occasionally fluorescence.

Swift SM Series Stereo Microscope

Stereo veterinary microscopes are used for basic quick viewing of samples at lower magnification and simple dissecting work. You can view all the Swift veterinary microscopes here.

Wednesday, July 25, 2012

Forensic Comparison Microscope

The Swift M3-F comparison microscope offers professional features at a competitive price point. Opaque objects can be viewed with the top LED illuminator and lower magnification of 20x. Large working distance provides plenty of room for bullets or larger evidence items. Microscopic specimens on slides can be viewed using the lower LED illumination and high power magnification of 40x, 100x or 400x.

Swift M3-F Forensic Comparison Microscope
Images can be viewed 100% from the left microscope, 100% from the right microscope, side-by-side, or overlapping. Multiple stage positions allow for a variety of specimen sizes. Rechargeable battery operated LED illuminators provide the option for using the forensic comparison microscope in the field. The microscope includes a lifetime warranty. You can learn more about the Swift M3-F forensic comparison microscope here.

Monday, July 23, 2012

Biological Microscope Viewing Trouble Shooting

There is nothing more frustrating than setting up the biology microscope, only to be unable to view a clear image. Below are a few trouble shooting pointers that may help!

When I look through my light microscope, I only see a dark outline of my sample.

Hold your slide up to the light. Are you able to see through the sample? If not, your sample is too thick. Try making another sample and slicing the specimen a bit thinner. (Kids your parents can help with this!) If you think you have the thinnest sample possible, try increasing the light (many microscopes have a rheostat control on the light). If neither of these suggestions work, try simply holding a flashlight above your sample. You won't be able to see through the sample, but it may illuminate the sample enough so that you can still view the surface of your specimen.

I can not locate my sample on the slide!

Always start with your microscope set to the lowest magnification (usually the 4x objective on your light microscope). Find the edge of the slide closest to the sample then slowly move the slide toward the area where light is shining. Once you get the sample into focus in the center of the microscope light, move the magnification up to 100x, then 400x.

My slide is spilling liquid all over the stage.

The best solution for viewing liquids is to use a depression slide with a cover slip. Use an eyedropper to place just a single drop of fluid in the well depression, then cover it with the cover slip. This should seal the liquid between the slide, flattening the specimen out enough to view it, without spilling your sample all over the microscope stage.

I am using a trinocular microscope, but when I look through the eyepieces the image is black.

Make sure the beam splitter is not engaged! This is the small rod that when activated, will block light from the eyepieces and send it up to the camera. Digital microscopes (with a camera built into the microscope) will usually also have a beam splitter.

Thursday, July 19, 2012

Microscope Magnification versus Resolution

A common misconception when selecting a new microscope (especially a children's microscope) is that the higher the magnification, the better the microscope. Magnification is simply the amount the specimen is magnified. For example, in order to view bacteria, you generally need a minimum magnification of 400x.

Bacteria under the microscope
Resolution however, is the most important factor, as it determines the clarity of the specimens being viewed through the microscope. Resolution is the ability to see objects that are small and close together as separate objects. The human eye can tell the difference between two objects that are about 0.3mm apart. Using a microscope, you can tell the difference between two objects that are 0.0003mm apart, or about 1,000 times better resolution.

Gypsum captured at 1000x magnification using the Digital BA210 microscope.

Magnifying an object 1000x is as good as it gets with a light microscope. In order to resolve even smaller objects, you would need to use a different kind of microscope known as a scanning electron microscope. Any light microscope that offers magnification above 1000x may magnify the object a lot, but the resolution will be poor.

Tuesday, July 17, 2012

Biological Microscope Parts

A biological microscope, also known as a light microscope or compound microscope, has multiple parts that are identified in the image below.

MW3-HB2 cordless binocular high school microscope.
  • Eyepiece: Microscope eyepieces (especially in biological microscopes) are typically 10x magnification. The eyepiece might have the ability to insert a reticle into it for making measurements. Some high school microscopes come equipped with a pointer in one of the eyepieces - this makes it easier for the teacher to point out specimens to students.
  • Siedentopf Head: A siedentopf binocular head differs from a sliding binocular head in that the eyepieces can be adjusted in a circular movement up and down, rather than simply sliding closer together or further apart. The Siedentopf head adjusts the interpupillary distance by turning (rotating) the eyetubes about a central axis (that also has the distance scale printed on it).  This system is designed to change the interpupillary distance without changing the tube length, so it is "compensation-free." In other words, you do not need to compensate for tube length changes manually. The sliding binocular head, is called "Jentsch," where the interpupillary distance is changed by moving the eyetubes closer together or farther apart in a linear fashion.  In this design, the tube length changes when changing interpupillary distance, so the user has to compensate for that by adjusting the "focus" setting of the eyepieces on a scale to correspond to the interpupillary distance used. Siedentopf is particularly helpful when multiple users are using the same microscope.
  • Carrying Handle: The best way to carry the microscope is to pick it up by the carrying handle and transport it while supporting the base.
  • Coarse Focus: The microscope coarse focus knob will move the stage (in some cases it will move the head of the microscope) to change the focus. Coarse focus moves in a larger increment than fine focus would and should be the first knob used to adjust specimen focus.
  • Fine Focus: Once the coarse focusing knob has been adjusted to get the specimen mostly into focus, the fine focus knob does exactly what the name describes - finely focuses the image.
  • Rheostat Light Intensity Control: This knob is adjusted in order to make the light brighter or dimmer.
  • Illuminator: The illuminator in this particular microscope is an LED light, which is a bright, cool light. Other lights you might find in a microscope include halogen (it heats up!), fluorescent (cool), or tungsten (also heats up). LED and halogen are usually the most common lights found in microscopes. LED light bulbs last much longer than halogen bulbs.
  • Condenser: The microscope condenser is a lens that concentrates light from the illuminator and focuses this light through the specimen and into the objective lens.
  • Mechanical Stage: A mechanical stage allows control of the slide without using your fingers - it consists of a slide holder and two knobs. The knobs allow for movement in the X or Y axis.
  • Slide Holder: The slide holder is part of the microscope stage that holds the microscope slide securely in place.
  • Objective Lens: The microscope objective lens gathers light from the object being observed and focuses the light rays to produce an image. The objective lens is also part of the overall magnification - the total magnification comes from a combination of the objective lens power and the eyepiece power.
  • Revolving Nosepiece: The revolving nosepiece holds the objective lenses in place and allows the user to switch from one magnification to another without removing the objective lens.

Friday, July 13, 2012

Choosing a Children's Microscope

Choosing the right type of microscope for your child can be somewhat daunting. There are multiple types of microscopes and different microscopes are used for different applications. Here are a few things to consider when looking to purchase a kids microscope.

What type of microscope should I buy?

First you must answer the question: What types of things do I want to examine under my microscope? If you would like to look at samples such as leaves, coins, rocks and objects that you can hold in your hand but would like to view a bit more detail - a dissecting microscope (also known as a stereo microscope) will be perfect for your needs.

The Swift SM102 dual power stereo microscope.

Stereo microscopes will usually have a light above and below the stage. Each light is independent of the other. You might use the light beneath the stage to look at a leaf or a butterfly wing. The light above the stage would be better for viewing rocks or coins.

Stereo microscopes come in two varieties:
  1. Single or dual magnification stereo microscopes - these microscopes allow you to switch back and forth between only one or two magnifications. They are typically less expensive than stereo zoom microscopes.
  2. Zoom magnification stereo microscopes - these microscopes provide a zoom range, for example from 10x-30x magnification. You would be able to see all magnifications within this zoom range. Using the example above, you would be able to view 10x, 11x, 12x, all the way up to 30x magnification.
A dissecting or stereo microscope also provides more working room under the microscope. The microscope is similar to a giant magnifying glass and you are able to put larger objects such as a big bug or rock under the microscope and still be able to focus the image.

The MW1-HB3 cordless student light microscope.
A light microscope or compound microscope is used for viewing biological specimens. The light is located beneath the stage, and the flat specimen placed on the stage (usually between a glass microscope slide with a cover slip) will need to allow light to pass through it in order to view a clear image. Because the light shines through the sample, it must be sliced very thinly, and be quite small. The microscope does not provide room for anything much larger than a microscope slide to fit on the stage beneath the objective lens.

Light microscopes are sometimes referred to as compound microscopes because they have more than one lens. A magnifying lens is a type of simple microscope. Compound microscopes have two lenses (an eyepiece and an objective lens) that are arranged so the light has to pass through both lenses before it reaches your eye.

A light microscope will typically provide 40x, 100x and 400x magnification. Some will provide 1000x magnification. These magnifications are a combination of the microscope eyepiece (10x) and objective lenses (4x, 10x, 40x and 100x).

Light Microscope Options:
  1. Corded light microscopes must be plugged into the wall in order to turn the light on.
  2. Cordless light microscopes run on either rechargeable or disposable batteries. These are best for use out in the field, in a barn, or if children will be walking between a table and the outlet and risk tripping on the cord and knocking the microscope off the table.
  3. Mirrored light microscopes are more rare since the invention of battery operated microscopes. They are often trickier to use, as the mirror must be positioned properly in order to allow light to shine up through the stage.

Images Captured with Stereo Microscopes vs. Compound Light Microscopes

The images below give you an idea of the types of things you might see with either a stereo dissecting microscope or a compound light microscope.

Diatom captured with a compound light microscope.
Leaf captured with a stereo dissecting microscope.
Sugar captured at 40x magnification with a stereo dissecting microscope.
Human blood cells captured at 400x magnification.

If you have any questions about selecting a student microscope, please don't hesitate to give us a call at 800-942-0528, or send an email, Microscope World is happy to help.

Wednesday, July 11, 2012

Microscope Reticles

Microscope World has recently added a variety of microscope reticles to its already wide selection. A microscope eyepiece reticle (also known as a reticule) is placed in the microscope in order to perform measurements or count particles.

The most commonly used microscope reticle is the ruler reticle. Available in a variety of lengths, both mm and inches, the ruler is simple to use and allows the end user to measure the distance between two items in a microscopic sample.

Grain sizing reticles are used for measuring twine, austenite, carbide, brass, and copper. Additionally, grain sizing reticles that meet ASTM E112 grain counting standards, Methods ASTM E-45 A, D and E method, and ASTM C method are specific reticles used to meet government required measuring standards.

Comparator reticles come in a variety of sizes and are sometimes referred to as protractor measuring reticles. Some comparator reticles have different size circles on them as well, helpful in measuring circular particles.

Whipple reticles are grids with a smaller grid inside the large one. The whipple measuring reticle is intended to enable the measurement of smaller specimen features such as pigment dispersions, colloidal particles, dust, and bacteria.

Cross line reticles are available with a simple cross, or more cross lines creating a pie. These cross line reticles are excellent for dividing a specimen into quadrants or measuring angles.

Point array reticles and point dot array reticles are helpful in counting and recognizing patterns.

In addition to the reticles shown above, there are a number of other specialized reticles available including Birnell Scale, Howard Mold counting, Walton & Beckett among many others. You can view all the microscope reticles and stage micrometers offered here.

Monday, July 9, 2012

Long-Spined Sea Urchin: Diadema Antillarum

A customer of Microscope World (Mr. Martin Moe) has been working on a project to secure viable culture methods for producing the Long-spined Sea Urchin, Diadema antillarum. He was kind enough to share many of his photos with us.

The Diadema Antillarum sea urchin is especially known for its long black spines. It is the most abundant and important herbivore on the coral reefs of the western Atlantic and Caribbean basin. When the population of these urchins is at a healthy level, they play a key part in preventing algae overgrowth on the reef, as they are grazers.

All images were captured using the Meiji MT4300 biological laboratory microscope.

"Teardrop" shape of juveniles that metamorphosis early: day 30-33.

Larvae with large rudiments: day 31.

An experimental settlement strip with settlers: day 41.

A cement settlement plate, no settlers or juveniles visible.

A new juvenile on the move: day 41.

 A day-old juvenile at the corner edge of a Petri dish: day 41.

New juvenile: day 41.

Juveniles on the side of an egg crate settlement plate: day 58.

Single juvenile on a rock in a small settlement tray: day 58.

Juveniles on a flat settlement plate: day 58.

Juvenile in a Petri dish with crustose coralline algae cover: day 58.

A big thank you to Mr. Martin Moe for sharing images from his hard work on this project with Microscope World. Hope you enjoyed the images as much as we did!

Thursday, July 5, 2012

Forensic Microscope Kids Science Project

Forensic science is the process of solving questions of interest in the legal system sometimes in relation to a crime. Forensic microscopes are often used in this process by law officials. These microscopes allow comparison of specimens.

Kids can do some of their own forensics at home with just a few basic tools!

One item that is often recovered from a crime scene is hair. Hair is examined in order to determine ethnicity or whether the hair may have been dyed recently. Using a compound high power microscope such as the kids microscope shown below, gather hair from several family members, your pets (Yes! Find the cat or dog brush and grab a strand from it), and even your best friend.

MW1-HB1 kids microscope - options for corded or cordless.

Place each strand of hair between a cover slip and a glass microscope slide. How do your family member's hairs differ from each other? What about the cat or dog? Do you notice that one color of hair is thicker than another? Usually brown hair is somewhat thicker than blond hair. Start out at the lowest magnification and work your way up to a higher magnification. Can you see any scales on the strand of hair at the higher magnification? Does the hair look healthy or damaged?

For your next forensic microscope science project, you will need a pencil, some tape and multiple friends or family members in order to take their finger prints. Rub a lot of lead from the pencil on a blank piece of paper then put your finger in the pencil lead. Next, press your finger onto a clean piece of tape. Pull the tape off slowly and then place the finger-printed tape onto a clean white piece of paper. Put this paper under a student stereo microscope, such as the one shown below.

Take a look at the finger prints you collected starting with the lower magnification, then move up to a higher magnification. Can you notice differences in the prints? How unique is each finger print?

Fingerprint image courtesy of US Dept of Commerce.

For your final forensic science project - gather some fibers from carpet and clothing. Place them under the stereo microscope using the top light. Would you be able to determine where these fibers originated? Does one of your friends have a different kind of carpet in their house? Do the fibers appear very different?

Carpet fibers captured at 40x magnification.

Carpet fiber captured at 10x magnification using the MW5-LD2 digital stereo microscope.

Tuesday, July 3, 2012

Copper Under the Microscope

Copper has the chemical element symbol Cu and atomic number 29. Copper is a highly thermal and electrically conducive metal. Pure copper is soft and quite malleable, usually with a reddish orange color. The major uses of copper are for electrical wires (60%), roofing and/or plumbing (20%), and industrial machinery (15%). Copper is primarily used as a metal, but when a higher hardness is required it is combined with other elements to make an alloy (about 5% of use) such as bronze or brass.

Copper photo courtesy of Jonathan Zander.

Because of copper's waterproof nature, it has been used as a roofing material for hundreds of years. The green color of these buildings, as shown in the image below, is due to a long-term chemical reaction. Copper is first oxidized to copper (II) oxide, then to cuprous and cupric sulfide and finally copper (II) carbonate, which is highly corrosion-resistant. Lightning rods use copper as a way to divert electric current through the ground rather than destroying the main structure.

Photo courtesy of Micah Clemens.
Minneapolis City Hall has a copper roof coated with patina.

Copper is an essential trace element in plants and animals. The human body contains copper at a level of about 1.4 to 2.1mg per kg of body mass. Copper is absorbed in the intestines, then transported to the liver bound to Albumin. After processing in the liver, copper is distributed to other tissues in the body. Because of its role in facilitating iron uptake, copper deficiency can produce anemia-like symptoms in humans.

Copper pipe captured at 10x magnification under a stereo zoom microscope using the MW5.1 CCD microscope camera and software.

25x magnification under a stereo microscope.

 45x magnification.

You will notice that the higher the magnification on the copper images captured above, the smaller the focused field of view. This is because the copper piece that was placed under the microscope was a curved piece of pipe, which provided less of a flat surface for focusing on. As magnification increases, the field of view decreases.