PRE-PUBLICA TION EDITION - Nelson Education

The following steps can be used to calculate thefield of view of a high-power lens.• Calculate the ratio of the magnification of thehigh-power objective lens to the magnificationof the low-power objective lens.ratio =• Use the ratio to determine the field of diameter(diameter of the field of view) under high-powermagnification.field of view diameter (high power) =field ____________________________of view diameter (low power)​ratioFor example, if the diameter of the low-powerfield of view is 2.5 mm, thenfield of view diameter (high power) = _______ 2.5 mm​10= 0.25 mmEstimating Size1. Measure the field of view, in millimetres, asshown above.2. Remove the ruler and replace it with the objectunder investigation.3. Estimate the number of times the object could fitacross the field of view.4. Calculate the width of the object:width of object =magnification of high-power lensmagnification of low-power lensFor example, if the low-power lens is 4×magnification and the high-power lens is 40×magnification, thenratio = 40 3 = 104 3Remember to include units.width of field of view________________________number of objects across field ​Putting Away the MicroscopeAfter you have completed an activity using amicroscope, follow these steps:1. Rotate the nosepiece to the low-power objectivelens.2. Raise the lenses (or lower the stage) as far aspossible.3. Remove the slide and the cover slip(if applicable).4. Clean the slide and the cover slip and returnthem to their appropriate location.5. Return the microscope, using two hands, to thestorage area.2.E. Using Other ScientificEquipmentFor some labs in this textbook, a specific list ofrequired materials and equipment is provided. Inothers, you have to decide what equipment andmaterials are necessary. Always keep safety in mindas you make your selections. Be sure to includeappropriate safety equipment, such as eye protection,gloves, or lab aprons, in your planning. For moreinformation on safety, refer to the Safe Science sectionof the Skills Handbook (page 600).608 Skills Handbook NEL