Chapter 2.pptx - How We See the Invisible World Chapter 2...

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How We See the InvisibleWorldChapter 2
Ch. 2 Learning Objectives1.Microscope History and Development(van Leeuwenhoek vs. Hooke vs. Galileo)2.Explain difference between transmission, reflection,refraction3.Explain how lenses are used in microscopy to manipulatevisible and ultraviolet (UV) light4.Explain difference between magnification & resolution5.Know the factors that affect resolution6.Know different types and differences betweenmicroscopes & electron microscopes7.Describe basic procedures of staining techniques
Invisible, but not truly…We can manipulate light for magnification to see microbes indifferent ways
Mostly we view microbes through the visible lightspectrumThis light behaves as electromagnetic waves and hassame properties:Wavelength – length between peaksAmplitude – height of peaksFrequency – rate of peaks in timeLonger wavelengths = lower frequency2.1 The Properties of Light
Light waves interact differently with objects or other light waves:1.Reflection - wave bounces off material2.Absorbance – wave is captured3.Transmission – wave travels through2.1 The Properties of Light
4. Interference – interacts w/ another wave5. Diffraction – wave is larger than object and scatters6. Refraction – change direction and/or speed2.1 The Properties of Light
Refraction is very important in microscopyMicroscopes use materials with different refractiveindices to achieve magnificationRefractive index – how much a material slows thespeed of light?????????? ?????=??????? ???h? ??????????????? ???h?h?h???? ????????Example: Refractive Index of glass== 1.52.1 The Properties of Light
Lens use refraction to direct light to an image pointConvex lens are used to magnify; refraction occurs on acurved boundary to meet a focal point(microscope)Concave lens refracts light away from a focal point (readingglasses)2.1 The Properties of Light

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Term
Fall
Professor
Elizabeth Carrington
Tags
Light Microscopes, Instruments of Microscopy