MAGNIFICATIONS & SCALES SI UNITS: 1 meter (m)= 1m 1 millimeter (mm) = 10-3m 1 micrometer (µm) = 10-6m 1 nanometer (nm) = 10-9m 1. (a) Determine the magnification of the string of Thiomargarita cells in Figure 11, if the scale bar represents 0.2 mm . (b) Determine the width of the string of cells. a) 0.2mm = actual size (X) 20mm 50 mm 0.2mm X 50mm 20mm Magnification = image size actual size 50mm 0.5mm size of object= 0.5mm = 100x OR a) Magnification = image size (scale) actual size (scale) b) 0.2mm = actual size (X) 20mm 25 mm 20mm 0.2mm 0.2mm X 25mm 20mm = 100x width of object= 0.25mm OR b) Magnification = image size actual size 100 = 25mm = 25/100 = X 0.25mm 2. In Figure 12 the actual length of the mitochondrion is 8µm. (a) Determine the magnification of this electron micrograph. (b) Calculate how long a 5 µm scale bar would be on this electron micrograph. (c) Determine the width of the mitochondrion. a) Magnification = image size = actual size b) 8000 = X__ 5µm 63mm 8µm 63000µm 8µm = 7875x ~ 8000x 8000 x 5 = 40,000µm = 40mm c) Depending on your measurement location the image width is b/w 20mm & 23mm. We will use 20mm. magnification (8000) = 20,000 µm = 20,000 / 80000 = 2.5µm X 3. The magnification of the human cheek cells from a compound microscope (Figure 13) is 2000X. (a) Calculate how long a 20 µm scale bar would be on the image. (b) Determine the average length of the cheek cells a) Magnification (2000) = ___X___ 20µm b) Length ~ 20mm 2000 = = 40,000µm = 40mm 20,000µm X 20,000/2000 = 10µm 4.(a) Using the width of the hen’s egg as a guide, estimate the actual length of the ostrich egg (Figure 14). (b) Estimate the magnification of the image. Actual hen egg width = 43mm Image hen egg width = 15mm Image ostrich egg = 45mm long a) Ostrich egg length = 43mm x 45mm = 43 x 3 = 129mm 15mm b) Magnification = image = 15mm = actual 43mm 0.33X