History of Microscopy - Lecture 11 PDF

the history of microscopy - lecture 11 Created @December 9, 2024 8:30 PM Class its whats the inside that counts Definitions and Early Concepts Microscope: An instrument for viewing objects t...

the history of microscopy - lecture 11 Created @December 9, 2024 8:30 PM Class its whats the inside that counts Definitions and Early Concepts Microscope: An instrument for viewing objects too small to be seen with the naked eye. Key Component: Glass lens, which bends light to magnify an image. Etymology: Lens: Derived from Latin "lentil," referencing the lentil-like shape of early lenses. Microscope: From Greek micro (small) and skopein (to look or see). Early History of Lenses Archimedes (212 BC): Alleged to have used burning lenses to focus sunlight and set enemy ships on fire. Historical accounts are doubtful due to practical limitations. Roman Contributions: Early experiments with glass lenses. Pliny the Elder: Documented lenses as tools for focusing sunlight to start fires and cauterize wounds. Recognition of magnifying effects by placing lenses over text. Roman Emperor Nero: the history of microscopy - lecture 11 1  Used an emerald to filter bright light during gladiator matches. Early example of wavelength filtering and "sunglasses." 800 AD: Abbott Fernes: Invented the "reading stone," a basic magnifying glass for enlarging text. Evolution of Microscopes 1. The First Compound Microscope (1595): Invented by Hans and Zacharias Janssen in Holland. Features: Two or more lenses (eyepiece and objective). Extendable tube for magnification adjustment. Capable of magnifying 10x to 30x. 2. Galileo Galilei (1609): Known for telescopes but also developed a compound microscope, the "Occhiolino" (little eye). Advocated for the heliocentric view, leading to controversy with the church. 3. Anthony van Leeuwenhoek (1632–1723): Used single-lens microscopes to magnify up to 270x. Achievements: First observations of bacteria, yeast, red blood cells, and spermatozoa. Sent discoveries to the Royal Society of London, but initially dismissed due to lack of formal training. 4. Robert Hooke (1625–1703): Built advanced compound microscopes with a light source. Published "Micrographia," detailing microscopic observations. the history of microscopy - lecture 11 2  Coined the term "cells" when observing cork slices. Contributions to Scientific Theories 1. Cell Doctrine (1839): Proposed by Schwann and Schleiden. Key Points: Cells are the basic structural and functional units of life. Cells exist as independent entities and building blocks. Schwann controversially omitted Schleiden's contributions in publication. 2. Modern Cell Theory (1858): Rudolf Virchow: Expanded the doctrine, stating all cells arise from pre- existing cells. Accused of plagiarizing Robert Remak's work. Industrial and Modern Advances 1800s: Microscopes became refined with precise engineering and improved lenses. Germany's Leadership: Companies like Zeiss and Schott dominated the industry. Key figures: Carl Zeiss, Ernst Abbe, and Otto Schott. Charles Spencer (Mid-1800s): Produced finely engineered microscopes with adjustable and flexible components. Fun Anecdotes and Notes Childhood microscopes: the history of microscopy - lecture 11 3  Many early designs mimic the simple functionality of Janssen's tube. The lecturer fondly recalls owning eight microscopes. Galileo's "Relics": After his death, followers preserved his fingers and teeth, now displayed in a Florence museum. A challenge to students: Aim for a legacy that lasts centuries. Key Points to Remember 1. Types of Microscopes: Simple Microscope: One lens. Compound Microscope: Two or more lenses. 2. Historical Figures: Janssen: Invented the compound microscope. Van Leeuwenhoek: Father of microbiology; first observations of microorganisms. Hooke: Coined "cells" and introduced light sources in microscopy. 3. Modern Relevance: Current light microscopes still operate on principles established by pioneers like Hooke and Galileo. 4. Scientific Progress: Builds on prior discoveries, often through collaboration and, occasionally, rivalry. the history of microscopy - lecture 11 4