The document provides instructions for calculating magnification and size measurements from electron microscope images using scale bars. It describes measuring the scale bar length, converting units, calculating magnification by dividing the measured scale bar length by its labeled length. It also explains measuring a specimen, dividing by the scale bar length to find how many bars long it is, and multiplying that by the scale bar size label to determine the specimen's actual size.

1. Scanning electron microscope image of a snout beetle
http://remf.dartmouth.edu/images/insectPart2SEM/source/20.html Image: public domain. Feb. 2012

2. Calculating Linear Magnification
of an Electron-Micrograph using it's scale bar
There are three steps:
Measure the length of the scale bar - in mm.
Convert your measurement into µm.
32mm
Calculate the magnification.
(Magnification = measured length /the number written.
As long as you have the SAME UNITS)
32 x 1000 = 32000µm
Magnifiation = the number of times bigger the scale bar actually is, compared to the
measurement written on it?
32000µm / 100 µm = 320x magnification

3. Scanning electron microscope image of a snout beetle
http://remf.dartmouth.edu/images/insectPart2SEM/source/20.html Image: public domain. Feb. 2012

4. Calculating Specimen Size
using a scale bar
There are four steps:
Measure the length of the Specimen in mm.
(show working)
Measure the length of the scale bar in mm.
Calculate how many scale bar lengths make the specimen.
(Divide length of specimen by length of scale bar)
Calculate the size. Multiply the scale bar label by the last answer.
(UNITS are the same as the scale bar)
2.6 x 100 µm = 260µm

5. Scanning electron microscope image of a snout beetle
http://remf.dartmouth.edu/images/insectPart2SEM/source/20.html Image: public domain. Feb. 2012
Magnifiation = x 320

6. Calculating Specimen Size
using magnification
There are three steps:
Measure the length of the Image of the Specimen in mm.
(show working)
Convert the length of the Specimen image to µm.
(x 1000)
Calculate the actual size.
Divide the length of the specimen image by the magnification
(UNITS are µm)

7. Electron microscope image of pollen grains from oriental lily.
http://remf.dartmouth.edu/images/botanicalPollenSEM/source/3.html Image: public domain. Feb. 2012

8. Calculating Linear Magnification
of an Electron-Micrograph using it's scale bar
There are three steps:
Measure the length of the scale bar - in mm.
Convert your measurement into µm.
Calculate the magnification.
(Magnification = measured length /the number written.
As long as you have the SAME UNITS)
Magnifiation = the number of times bigger the scale bar actually is, compared to the
measurement written on it?
magnification

9. Electron microscope image of pollen grains from oriental lily.
http://remf.dartmouth.edu/images/botanicalPollenSEM/source/3.html Image: public domain. Feb. 2012

10. Calculating Specimen Size
using a scale bar
There are four steps:
Measure the length of the Specimen in mm.
(show working)
Measure the length of the scale bar in mm.
Calculate how many scale bar lengths make the specimen.
(Divide length of specimen by length of scale bar)
Calculate the size. Multiply the scale bar label by the last answer.
(UNITS are the same as the scale bar)

11. Electron microscope image of pollen grains from oriental lily.
http://remf.dartmouth.edu/images/botanicalPollenSEM/source/3.html Image: public domain. Feb. 2012
Magnification = x 2500

12. Calculating Specimen Size
using magnification
There are three steps:
Measure the length of the Image of the Specimen in mm.
(show working)
Convert the length of the Specimen image to µm.
(x 1000)
Calculate the actual size.
Divide the length of the specimen image by the magnification
(UNITS are µm)

13. Human leukocyte - showing golgi apparatus
http://remf.dartmouth.edu/images/humanBloodCellsTEM/source/3.html Image: public domain. Feb. 2012

14. Calculating Linear Magnification
of an Electron-Micrograph using it's scale bar
There are three steps:
Measure the length of the scale bar - in mm.
Convert your measurement into nm this time.
Calculate the magnification.
(Magnification = measured length /the number written.
As long as you have the SAME UNITS)
Magnifiation = the number of times bigger the scale bar actually is, compared to the
measurement written on it?
magnification

15. Calculating Specimen Size
using a scale bar
There are four steps:
Measure the length of the Specimen in mm.
(show working)
Measure the length of the scale bar in mm.
Calculate how many scale bar lengths make the specimen.
(Divide length of specimen by length of scale bar)
Calculate the size. Multiply the scale bar label by the last answer.
(UNITS are the same as the scale bar)