magnification and size
DESCRIPTION
Magnification and Size. Measuring biological specimens using millimetres as units. To accurately measure the size of cellular structures we need a suitable scale:. Ideally, we need a scale we can see directly alongside the cells we are observing:. Start by putting a ruler under the microscope:. - PowerPoint PPT PresentationTRANSCRIPT
Magnification and SizeMagnification and Size
Measuring biological specimens using millimetres as units
Measuring biological specimens using millimetres as units
To accurately measure the size of cellular structures we need a suitable scale:
To accurately measure the size of cellular structures we need a suitable scale:
Ideally, we need a scale we can see directly alongside the cells we are
observing:
Ideally, we need a scale we can see directly alongside the cells we are
observing:
Start by putting a ruler under the microscope:
Start by putting a ruler under the microscope:
Appearance of ruler at medium magnification
Appearance of ruler at medium magnification
Appearance of tissue at medium magnification
Appearance of tissue at medium magnification
Estimating cell size at medium magnification
Estimating cell size at medium magnification
1 mm
1 mm
12
5
1mm / 12 cells = 0.083 mm
1mm / 5cells=
0.2 mm
Other unitsOther units
Mean width of cells = 0.083 x 1000 = 83µm
Mean length of cells = 0.2 x 1000 = 200µm
Diameter of field of
view/mm
No. of cells
lengthways
No. of cells
widthways
Mean length (mm)
Mean width (mm)
1.00 5 12 0.2 0.083
1mm = 1000µm
Calculating actual size:Calculating actual size:
Calculating magnification & actual size:Calculating magnification & actual size:
Calculating actual size:Calculating actual size:
Calculating magnification:Calculating magnification:
Calculating magnification & actual size:Calculating magnification & actual size:
Calculating actual size:Calculating actual size:
Cell MagnificationCell Magnification
This diagram shows the general structure of an animal cell from an electron microscope.
Calculate the magnification factor.
Calculate the length of G - a mitochondrion.
Calculate the diameter of the nucleus.
Calculate the width of the cell at its widest part.
____ 0.005 mm
Plant cell magnificationPlant cell magnification
____ 0.040 mm
Diagram shows the generalised structure of a plant cell as seen with an electron microscope.
Calculate the magnification factor.
Calculate the width of the cell.
Calculate the length of the vacuole.
Magnification of an Illustration = Size of Illustration / Actual Size
For example, a magnification of 1x means the illustration is the same size as the object, 100x means the illustration is 100 times bigger than the object, etc. It is important that you first calculate or measure the actual size of an object, and from that calculate the magnification of the illustration .
Always draw the magic triangle and fill in the information you have.
Always check your units.
Magnification of an Illustration = Size of Illustration / Actual Size
For example, a magnification of 1x means the illustration is the same size as the object, 100x means the illustration is 100 times bigger than the object, etc. It is important that you first calculate or measure the actual size of an object, and from that calculate the magnification of the illustration .
Always draw the magic triangle and fill in the information you have.
Always check your units.
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