Practical: Investigation into Size and Scale of Microscopic Tissues 
Practical 1 - Investigation into size and scale of microscopic tissues
This practical focuses on microscope technique and using graticules and stage micrometers to determine size and scale in biological cells and tissues.
Intended learning outcomes
By the end of this practical you should be able to:
• Use a microscope fitted with an eyepiece graticule and stage micrometer
• Calibrate the eyepiece graticule using the stage micrometer
• Use the calibrated graticule to determine the actual size of microscopic specimens
• estimate the accuracy of a measurement
• Use the graticule to determine scales
• Understand the importance of repeating or validating set of results.
Safety Information
There are no particular hazards in this practical, however you must follow your laboratory rules.
Background information
• The measurement of specimen size with a microscope, is made by using an eyepiece graticule. This is a glass or plastic disc with 8 divisions etched onto its surface, which is inserted into the eyepiece lens.
• The size of the eyepiece graticule remains constant, despite the fact that the image viewed will change its size depending upon whether high- or low-power objective lenses are used. For example a cell viewed with the x40 objective will appear much larger than when viewed with the x10 objective. However because the graticule is in the eyepiece it will not change its size. Therefore the value of each of the divisions in the eyepiece graticule varies with the magnification of the objective lens.
• A stage micrometer is a very accurately etched glass or plastic ruler that is placed on the microscope stage so that the eyepiece graticule scale is superimposed on the stage micrometer scale. The scale is usually 1mm divided into 100 separate divisions so that each division equals 10 micrometres (10μm).
• It is necessary to calibrate the eyepiece graticule with the stage
This practical focuses on microscope technique and using graticules and stage micrometers to determine size and scale in biological cells and tissues.
Intended learning outcomes
By the end of this practical you should be able to:
• Use a microscope fitted with an eyepiece graticule and stage micrometer
• Calibrate the eyepiece graticule using the stage micrometer
• Use the calibrated graticule to determine the actual size of microscopic specimens
• estimate the accuracy of a measurement
• Use the graticule to determine scales
• Understand the importance of repeating or validating set of results.
Safety Information
There are no particular hazards in this practical, however you must follow your laboratory rules.
Background information
• The measurement of specimen size with a microscope, is made by using an eyepiece graticule. This is a glass or plastic disc with 8 divisions etched onto its surface, which is inserted into the eyepiece lens.
• The size of the eyepiece graticule remains constant, despite the fact that the image viewed will change its size depending upon whether high- or low-power objective lenses are used. For example a cell viewed with the x40 objective will appear much larger than when viewed with the x10 objective. However because the graticule is in the eyepiece it will not change its size. Therefore the value of each of the divisions in the eyepiece graticule varies with the magnification of the objective lens.
• A stage micrometer is a very accurately etched glass or plastic ruler that is placed on the microscope stage so that the eyepiece graticule scale is superimposed on the stage micrometer scale. The scale is usually 1mm divided into 100 separate divisions so that each division equals 10 micrometres (10μm).
• It is necessary to calibrate the eyepiece graticule with the stage