Made with Xara

Using the microscope Equipment needed  A compound optical microscope with x10, x20 and x40 objectives and a x10 eyepiece.  An eyepiece micrometer.  A stage micrometer for calibrating the eyepiece. Optical views - optical section & surface view The optical section is seen when the focus is at the equator, and surface view refers to almost everything above the equator and varies with the point of focus. Examining micro slides Always begin by using the lowest power objective.  Centre the subject to be examined and then, if necessary, change to the next highest power.  Repeat until the desired power of magnification is achieved. At x400 and above details of the exine may be observed. Pollen grains will adopt a variety of attitudes on the micro slide, so look at them from as many angles as possible.  Compare one grain with another looking at as much detail as possible.  Continue looking and focusing at different powers until a conclusion is reached. Diagrams of cross sections of exine are usually prepared from observations employing a scanning electron microscope.  This degree of magnification cannot be achieved with a compound microscope. Measuring with the microscope The unit of measurement is a millionth of a metre, a micrometre, previously called a micron. Measurements as made using a graduated scale located in the eyepiece of the microscope just below its lower lens.  This is referred to as an eyepiece micrometer.  The size of the image will change with every objective used and it is necessary to calibrate the eyepiece scale for each.  To do this a second scale is required and this is called a stage micrometer. Instead of an object for study it has a scale, usually 1mm long divided into 100 parts. Each division is therefore 10 micrometer.  It is now possible to give a value in micrometers to each division on the eyepiece scale for each objective lens.