Stereo microscopes (sometimes called "dissecting" microscopes) use two eyepieces to see objects in 3-D. Each eyepiece has its own objective lens. These microscopes act as giant magnifying lenses and allow you to see fine detail on the surface of your specimen. The light source is usually emited from above the specimen. Many will also have a bottom light for viewing translusent objects or slides. Because of the low power of these microscopes (from 10X to 60X) they work best with objects visible to the naked eye. Stereo microscopes have only a course focus, and the distance between the objective and the specimen is quite large. These microscopes are best for general exploration of large to small, but still visible objects. They are great for young children, because they do not need to prepare a slide to put the specimen on. Almost any thing they find indoors or out, can make a specimen to explore. They can take a close up look at just how it is made. Stereo scopes are often used in industry and manufacturing for assembling of small parts and inspections.
Fun (and useful) for all ages.
Compound microscopes can also use multiple objective lenses, but all lenses are connected to a single eyepiece- each lens sees exactly the same image, only at different magnifications. Compound microscopes contain multiple lens types and sizes, greatly multiplying the range of magnification (40X to 1000X). Each objective is mounted on a turret for easy switching. The light source is usually emited from below the specimen, allowing the viewer to see through the sample. Thus, specimens must be very small, sliced very thinly, and sometimes stained to illuminate detail. Most compound microscopes contain both course and fine focus controls, and the distance between objective and specimen is very small. These microscopes are best for examining great detail of tiny objects, invisible to the naked eye. They are the recommended type of scope for highschool biology.
Determining magnification for any microscope is easy; multiply the magnification of the objective with the magnification of the eyepiece. For example, stereo microscope 400-10-2 has a 2X objective magnification and a 10X eyepiece magnification, resulting in a maximum 20X magnfication. Compound microscope #131 has 3 objective lenses of 4X, 10X, and 40X magnification and an eyepiece of 10X magnification, resulting in magnifications of 40x, 100x and 400X. Most compound microscopes have three or four objective lenses mounted on a turret so they can be switched easily.
Oil immersion microscopes are not necessary for magnifications up to 400X, but they are essential to view specimens at 1000X. At this high power of magnfication, the refraction of the light as it leaves the glass slide causes the image to become unclear. Oil has the same properties of light as glass does. Replacing the air between the slide and the objective lens with immersion oil prevents the distorted image. Oil immersion microscopes are necessary for high quality work with very high magnification. They usually have both an Abbe condenser and and Iris diaphragm to focus the light on the slide properly. Most often used at college level courses, and in the medical field.
Incandescent light is your normal bulb light. The incandescent lights in these microscopes are created with tungsten bulbs. Microscopes illuminated with incandescent light bulbs are the least expensive. The color produced by an incandescent light bulb is usually yellowish. This type of bulb requires more energy than other types and produces more heat.
Halogen light is a bright white light that also generates much heat. While much brighter and with less color than incandescent.
Fluorescent light bulbs produce more light than incandescent ones. The color is whiter, and they require much less energy than incandescent bulbs. They do not produce much heat.
LED-illuminated microscopes use very little energy, so they can even be cordless! LEDs produce a bright white light without heat, the perfect conditions for viewing live specimens. LED illumination lasts longer than any other type - no burned out lightbulbs! LED microscopes may be labeled CLED (Corded LED) or LED (Cordless LED).
Harness the power of digital technology! Each digital microscope comes with a high-definition camera and software for viewing your slides on computer, projector, or monitor. Digital pictures of slides can be stored easily on your computer, or students can watch live action footage of the invisible world. No more taking turns at the microscope!
Abbe condenser—a complicated illumination system that focuses the light in a specific part of the slide to improve the clarity of the image. In order to focus the light, it must be able to move up and down and increase and decrease the opening the light comes through.
Achromatic—the lens is designed so that it doesn’t break the light into different colors. This allows the colors of the specimen to be more accurately seen when magnified.
Binocular/Monocular—number of eyepieces on a microscope. A binocular microscope has two eyepieces; a monocular microscope has one. The two eyepieces of a binocular microscope may show the same image or not, depending on whether the eyepieces are connected to separate objective lenses or not.
Calibrated—the focus knob is marked with measurements stating how far the stage moves with each turn of the knob.
Coarse Focus—this is used to move the objective lenses higher and lower to get a better focus on the specimen (also see Fine Focus). All microscopes should have this.
Coaxial focusing—the coarse and fine focus knobs are mounted inside each other (see picture to left).
Condenser lens—a lens located below the stage to focus the light onto the specimen. Only needed in high power microscopes.
Contrast plate—an opaque plate placed on the stage of a low power microscope. One side is white; the other is black to contrast with the specimens being viewed.
Diaphragm—something placed above the light source of a microscope to adjust the intensity of the light. Diaphragms are of two types: Disc and Iris.
DIN—stands for “Deutsche Industrial Normen.” It refers to the length of the objective lens. The DIN is a standard length: 160mm.
Diopter adjustment—a focusing mechanism for just one of two eyepieces to compensate for the differences between the two eyes.
Disc Diaphragm—a disc diaphragm is a disc with holes of varying sizes. As the disc is turned, the amount of light passing through the specimen is adjusted (see picture to left).
Filter—a device that permits some wavelengths of light to pass through without allowing others, often blocking some colors while allowing some to continue.
Fine Focus—this is used to fine-tune the focus after the coarse focus has already been used. Only higher level microscopes will have this (eg. #131, #132, #125, #126, #160). This focus is necessary for the Apologia Biology courses. Sometimes the fine and coarse focus knobs are separate; sometimes the fine focus knob is located inside the coarse focus knob.
Fluorescent illumination—fluorescent bulbs are brighter, cooler, and longer-lasting than the standard incandescent light bulbs.
Incandescent illumination—the standard (and least expensive) light source for the microscope. The light produced by this type of bulb is hotter, more yellow, and requires more energy than its more expensive replacements.
Incidental illumination—light source above the specimen
Inclination—the #106 microscope has a joint which allows the eyepiece and stage to be moved at an angle to the base.
Iris diaphragm—an adjustable diaphragm. It can be adjusted gradually to increase or decrease the light source (see picture to right).
LED illumination—stands for “light-emitting diode.” This type of illumination is cool and very low energy compared with the standard incandescent lighting system or the fluorescent lighting system, allowing for use of live specimens and cordless power sources.
Magnification—the amount the specimen is magnified by the lenses of the microscope, such as 10X (magnified 10 times). If the eyepiece and objective lenses have separate magnifications, the powers are multiplied together to determine the actual magnification (10X eyepiece and 40X objective=400X magnification).
Nose piece—the part of the microscope to which the objective lenses are attached. It rotates so that different objective lenses can be used. Also called Objective Turret, or Turret.
Objective turret—the part of the microscope to which the objective lenses are attached. It rotates so that different objective lenses can be used. Also called Nosepiece or Turret.
Objective—the lens of the microscope. See picture to left.
Oil immersion—when light moves through air, it is slightly distorted, distorting the image seen through the microscope when using very high powers of magnification. With an oil immersion lens, this distortion can be decreased. Oil immersion lenses are designed to be used with a drop of immersion oil filling the space between the slide and the lens. Oil cannot be used with lenses not designed to be used without it. Oil immersion microscopes require an Abbe condenser and an Iris diaphragm
Parcentered—the microscope stays centered when you switch from one objective to another.
Parfocal—the microscope stays in focus when you switch from one objective to another.
Rack and pinion—a pair of gears to convert circular motion into linear motion. The circular motion is applied to a circular gear (the pinion) which is transferred to the linear gear (the rack). See picture to left.
Rack stop—this prevents the user from cranking the objective lenses too low and cracking the slide
Rheostat light—a light that has a dimmer to adjust the amount of light produced.
Slip Clutch—used to prevent damage caused by turning the focusing knob too far in either direction.
Stage Clips—metal pieces that attach the slide to the stage (the part of the microscope where the slides sit).
Stage Plate—a frosted circular glass plate that fits in over the light source of a low power microscope.
Substage illuminator—a light source located below the stage (or where the slides are located).
Tension adjustment—prevents the coarse focus knob from turning on its own due to the weight of the stage.
Transmitted illumination—light source below the specimen
Turret—the part of the microscope to which the objective lenses are attached. It rotates so that different objective lenses can be used. Also called Objective Turret, or Nosepiece.
Widefield eyepiece—eyepiece lenses that have a larger area of the lens that allows for clear viewing. This makes the viewing “hole” seem larger and allows the user to move more while still being able to view the specimen.