magnification and microscopes

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Microscopes!

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Mutual dependence: Science & Technology

Technology…the pragmatist Does it work? Is it useful? Is it sustainable?

Science…the idealist What is it? How does it work? What does it tell us?

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Mutual dependence: Science & Technology

Microscopes Electron microscopes

Higher resolution Dead samples Expensive

Optical (light) microscopes Lower resolution Live samples Less expensive

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Micrographs

Scanning electron micrograph (SEM) of various Pollen. Public domain image reference: Dartmouth Electron Microscope Facility, Dartmouth College

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Size matters micron = micrometer = 1/1,000,000 meter diameter of human hair = ~20 microns

Miss N, Show them the interactive!!

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Microscopic units of measurement

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1 metre (m) = ________ millimetres (mm)

1 mm = ________ microns (µm)

1 µm = ________ nanometres (nm)

1 mm = ________ nm

1 m = ________ µm

1 m =________ nm

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1 m = 1,000 mm = 103mm

1 mm = 1,000 µm= 103µm

1 µm = 1,000 nm= 103nm

1 mm = 1,000,000 nm = 106nm

1 m = 1,000,000 µm = 106µm

1 m = 1,000,000,000nm =109 nm

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10-3 m = ______ m = _____mm

10-6 m = ______ m = _____mm

10-9 m = ______ m = _____mm

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10-3 m = 0.001m = 1 mm

10-6 m = 0.000001 = 1 µm

10-9 m = 0.000000001= 1nm

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Electron microscope range:

_____ to _____

Light microscope range:

_____ to _____

Unaided human eye range:

_____ to _____Unaided?

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Electron microscope range:

1 nm to 100 µm

Light microscope range:

1 µm to 1 mm

Unaided human eye range:

1 mm upwards

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Name that micrograph

Light microscope or Electron microscope?

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Regents Biology19 Light microscope

Unstained

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Regents Biology20 Light microscope

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Regents Biology22 Light microscope

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Tick

Regents Biology23 Electron microscope

Tick

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Regents Biology24 Electron microscope

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Regents Biology25 Light microscope

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Regents Biology26 Electron microscope

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Aphid

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Aphid

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Regents Biology28 Light microscope

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Regents Biology29 Light microscope

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Regents Biology30 Electron microscope

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Regents Biology31 Electron microscope

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Regents Biology32 Electron microscope

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Regents Biology33 Electron microscope

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Regents Biology35 Light microscope

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Regents Biology36 Light microscope

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Regents Biology37 Light microscope

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THE END!

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Magnification

Magnification = ocular lens x objective lens

A microscope has an eyepiece lens with a power of 20X.  The objective lens being used has a power of 10X. What is the total magnification?

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Using Scale Bars

Using a scale bar:The image at right is of a virus-like particle. The bar represents 50nm. It is observed under x200. Calculate the actual size of the image.

50nm

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Image is 50nm in diameter

Using a scale bar:

50nm

Using Scale Bars

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A specimen is 1cm in diameter under a power of x600. What is the actual size of the specimen?

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Magnification: I AM

Watch yo units!!

Image size

Actual size Magnification

Measure with ruler

Need to figure this out

Given to us

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1. Measure the size of the image. …..1cm (10mm)

2. Find the actual size of the sampleI/AM I=10mm M=600A=?

A=10mm/600 = 0.0167mm =16.67 µm

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Your Turn!