Microscope Math Biology 11. Don’t forget to always use units with numbers! ‘times larger’ or...
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Transcript of Microscope Math Biology 11. Don’t forget to always use units with numbers! ‘times larger’ or...
Microscope MathMicroscope MathMicroscope MathMicroscope Math
Biology 11Biology 11
Don’t forget to always use units with numbers!
‘times larger’ or ‘x’mm µm
Total MagnificationReview
Formula:Total Magnification =
(eyepiece)(objective)
Low: (10)(4) = 40xMedium (10)(10) = 100xHigh (10)(40) = 400x
Field of View
• Diameter (widest distance across) of the circle of light when looking through the microscope
• Expressed in µm (micrometers)
Micrometers (µm)
• 1 µm = 0.001 mm• 1 mm = 1000 µm
• To convert: Move decimal 3 places!
• Example: 7752 µm= 7.752mm
Measuring the Field Diameter (Low
Power)
1. Place ruler across center of field of view
2. Line up the middle of a mm mark against one side of field of view
3. Count the number of full mm spaces.- Estimate amount of next
mm if not complete
4. Record results on board
Field DiameterWe will use the following field diameter sizes.
Record the µm measurements on your sheet.
Total Magnificati
on
Measurement (mm)
Field Diameter
(µm)
Low (40x) 4.2 4200
Medium (100x)
1.68 1680
High (400x) 0.42 420
Estimating Specimen Size
• If you know how wide your field of view is you can estimate the size of specimens being viewed
• Expressed in µm (micrometers)
Estimating Specimen Size
Formula:
Estimated length = Field Diameter (µm)
Fit number
What is a “fit number”?
• NUMBER of times an object FITS across the field of view
• No units are used!
Example
• How many times can this ball fit across the field of view?
Fit number is 3
If we viewed the ball with low power …
Formula:Estimated length = Field of View
(µm)Fit number
= 4200 µm 3
= 1400 µm
Because it was viewed
on low power
Any Questions?
• Let’s practice!
Diagram Magnification
• How many times larger your diagram (or scientific drawing) is than the actual specimen
• Expressed as “times larger” or “X”
Diagram Magnification
Formula:Diagram magnification =
Diagram size (µm) Estimated Size
What is the “diagram size”?
• How large your diagram (or scientific drawing)
• Expressed in µm
• How to find?– Measure your diagram in mm– Multiply by 1000
Example
1. Diagram the “specimen” below.
2. Determine the fit number.
3. Calculate the estimated size.
Example (cont.)
4. Determine the diagram size in micrometers.
5. Calculate the diagram magnification.
Any Questions?
• Let’s practice!