light microscope vs. electron microscope

of 25 /25
LIGHT VS. ELECTRON MICROSCOPE PRESENTED BY: GROUP 1: REMIEL ALQUILETA JAMICA AMBION CELLINE ANCHETA HUB 42

Author: jamica-ambion

Post on 15-Jan-2017

106 views

Category:

Science


7 download

Embed Size (px)

TRANSCRIPT

BACKGROUND

Light vs. Electron microscopePresented by:Group 1:Remiel AlquiletaJamica AmbionCelline AnchetaHUB 42

Historythe 1590's, two Dutch spectacle makers, Zacharias Jansen and his father Hans started experimenting with these lenses

HistoryAnton van Leeuwenhoek a Dutch draper and scientist, and one of the pioneers of microscopy who in the late 17th century became the first man to make and use a real microscope.

HistoryHooke's Micrographia, is Robert Hookes most famous work and is notable for the stunning illustrations, drawn by himself.

HistoryModern compound microscopesWith the advancement of technology and improved optics, the microscope as we know it today came into being.

Uses of Microscope

CytologyPharmacoloyMicrobiologyHistology

RESOLVING POWERAbility of a microscope to differentiate between two close together objects.Higher resolution means that objects are closer together and can be seen as separate points.

Light MicroscopeThe termlightrefers to the method by which light transmits the image to your eye.Microscopeis the combination of two words; "micro" meaning small and "scope" meaning view.Optical microscopes are the oldest design of microscopeUsing alight microscope, onecanview cell walls, vacuoles, cytoplasm, chloroplasts, nucleus and cell membrane.Light microscopesuse lenses andlight to magnify cell parts.

Types of Light MicroscopeAsimple microscopeis a microscope that uses a lens or set of lenses to enlarge an object through angular magnification alone, giving the viewer an erect enlargedvirtual image. Simple light microscopes of the past could magnify an object to 266X

Types of light microscopeDissecting microscope- magnification: 10-40x- not use for cellular level- specimens can be living or non-living.

Sample image from dissecting microscope

Types of Light microscopeAcompound microscopeis a microscope which uses a lens close to the object being viewed to collect light (called theobjectivelens) which focuses areal imageof the object inside the microscopeModern compound light microscopes, under optimal conditions, can magnify an object from 1000X to 2000X

Sample images from light microscope

AdvantagesLimitationEasy to useCheapTrue color but sometimes require stainingCould use live specimensLow resolution due to shorter wavelength of light (0.2nm)Low magnification (max. 1250x)Specimen used is thin

Electron MicroscopeAnelectron microscopeis a microscope that uses a beam of acceleratedelectronsas a source of illuminationA transmission electron microscope can achieve better than 50pm resolution andmagnificationsof up to about 10,000,000xYou need to use particles that are smaller than photons to start with: in other words, you need to useelectronsIn an electron microscope, a stream of electrons takes the place of a beam of light and allows us to see things smaller even than light itself.

Scanning Electron microscopeA Scanning electron microscopes are designed to make images of the surfacesof tiny objects.Advantages:- High resolution (1nm)- Provide detailed images of surface structures.- High magnification (200,000x)- 3D images

SEMLimitations:- expensive- requires extensive training- sample must be dead (vacuum, stained)- black and white/false colour image

Transmission Electron MicroscopeTransmission electron microscopes are the most powerful electron microscopes: we can use them to see things just 1nanometerin size, so they effectively magnify by a million times or more.Atransmission electron microscopefires a beam of electronsthrougha specimen to produce a magnified image of an object.

AdvantagesDisadvantagesHigher resolution (1nm)Provides detailed images of interior structuresHigher magnification (500,000x)

ExpensiveExtensive training requiredSamples must be dead (vacuum, stained)Black and white/ False colour images

Summary

RefencesComparing microscopes: https://www.youtube.com/watch?v=b4WOsYktdn4Microscopes - SC.912.L.14.4 https://www.youtube.com/watch?v=6vZZeWqbmU8http://www.cas.miamioh.edu/mbiws/microscopes/compoundscope.html#howit workshttp://www.history-of-the-microscope.org/history-of-the-microscope-who-invented-the-microscope.php

Laboratory Reagent and Preparations CalculationCalculate the grams of each substance required to prepare the following solutions:a. 50 mL of 0.4 M sucroseb. 100 mL of 0.5 M H2SO4

Solutions!