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