INTRODUCTION TO LABORATORY EQUIPMENT AND MACHINES
These are machines and equipment that are used in the laboratory for carrying out clinical assay on biological samples. These machines increase the speed of carrying out these assays and also improve the accuracy of the results obtained.
PRINCIPLE OF OPERATION: The most commonly used microscope for general purposes is the standard compound microscope. It magnifies the size of the object by a complex system of lens arrangement.
It has a series of two lenses; (i) the objective lens close to the object to be observed and (ii) the ocular lens or eyepiece, through which the image is viewed by eye. Light from a light source (mirror or electric lamp) passes through a thin transparent object. The objective lens produces a magnified ‘real image’ first image) of the object. This image is again magnified by the ocular lens (eyepiece) to obtain a magnified ‘virtual image’ (final image), which can be seen by eye through the eyepiece. As light passes directly from the source to the eye through the two lenses, the field of vision is brightly illuminated. That is why; it is a bright-field microscope.
TYPES OF MICROSCOPES
Light Microscope - the models found in most schools, use compound lenses to magnify objects. The lenses bend or refract light to make the object beneath them appear closer. Common magnifications: 40x, 100x, 400x.
Stereoscope - this microscope allows for binocular (two eyes) viewing of larger specimens.
Scanning Electron Microscope - allow scientists to view a universe too small to be seen with a light microscope. SEMs do not use light waves; they use electrons (negatively charged electrical particles) to magnify objects up to two million times.
Transmission Electron Microscope - also uses electrons, but instead of scanning the surface (as with SEM's) electrons are passed through very thin specimens.
PARTS OF A COMPOUND MICROSCOPE
Eyepiece: The lens the viewer looks through to see the...