MAGNIFICATIONS SCALES SI UNITS 1 meter m 1

MAGNIFICATIONS & SCALES SI UNITS: 1 meter (m)= 1 m 1 millimeter (mm) = 10 -3 m 1 micrometer (µm) = 10 -6 m 1 nanometer (nm) = 10 -9 m

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. 2 mm = actual size (X) 0. 2 mm X 50 mm size of object= 0. 5 mm 20 mm 50 mm 20 mm Magnification = image size 50 mm = 100 x actual size 0. 5 mm OR a) Magnification = image size (scale) 20 mm = 100 x actual size (scale) 0. 2 mm b) 0. 2 mm = actual size (X) 0. 2 mm X 25 mm width of object= 0. 25 mm 20 mm 25 mm 20 mm OR b) Magnification = image size 100 = 25 mm = 25/100 = 0. 25 mm actual size X

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 = 63 mm 63000µm = 7875 x ~ 8000 x actual size 8µm b) 8000 = X__ 8000 x 5 = 40, 000µm = 40 mm 5µm c) Depending on your measurement location the image width is b/w 20 mm & 23 mm. We will use 20 mm. 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 2000 X. (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___ = 40, 000µm = 40 mm 20µm b) Length ~ 20 mm 2000 = 20, 000µm 20, 000/2000 = 10µm X

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 = 43 mm Image hen egg width = 15 mm Image ostrich egg = 45 mm long a) Ostrich egg length = 43 mm x 45 mm = 43 x 3 = 129 mm 15 mm b) Magnification = image = 15 mm = 0. 33 X actual 43 mm