PPT-Unit 5 – Light and Atoms

ASTR 101 Prof Dave Hanes The Pessimist writing in 1835 On the subject of stars all investigations which are not ultimately reducible to simple visual observations arenecessarily denied to us We shall never be able by any means to study their chemical . Atoms emit and absorb light First Test is Thurs Feb 1 st About 30 multiple choice questions Some require working with models such as phases of Venus zodiac Fig 212 Click on Study Guide 2005 Test on Syllabus Class of 30 th is not on test Hom hole. hole. Answer the following questions for both packing diagrams.. Find the smallest unit that, if repeated, would give you the entire structure. This is the unit cell. Draw a box on the diagram representing the unit cell.. Who first thought of the atom?. Democritus. Leucippus. Democritus and Leucippus. ~440 BC. They were the first philosophers that believed that atoms existed.. They thought that you could cut something in half , over and over, until you eventually get to a particle so small that it can no longer be cut In half.. ction to materials physics #4. Week 4: Application of electromagnetic interaction. 1. Chap. 1-3:. Table . of contents. Application of electromagnetic interaction. Review of the last week. Mutual relation among optical, electric and atomic properties. Flame Test . Flame Test. According to Bohr theory of the atom, electrons may occupy only specific energy levels. Electrons in atoms jump from their ground state to excited states by absorbing energy. Eventually these electrons fall back to their ground state, reemitting the absorbed energy in the form of light. Because each atom has a unique structure and arrangement of electrons, each atom emits a unique spectrum of light. This characteristic light is the basis for the chemical test known as a flame test. In this test, being placed within a flame excites the atoms. As they reemit the absorbed energy in the form of light, the color of the flame changes. For most metals, these changes are easily visible. However, even the presence of a tiny speck of another substance can interfere with the identification of the true color of a particular type of atom. . 1. 0. .1 . What is Light?. The sun emits large amounts of energy in all directions. Some of this solar energy reaches Earth and heats the Earth’s surface. . SOURCES:. a. Natural . . ex: sun, fireflies. ASTR 101. Prof. Dave Hanes. Think . About Clocks. They . are designed to . measure and mark the passage of . time, . by monitoring some regular, repeated mechanical action. . . There are Other Ways!. Darrick. Chang. ICFO – The Institute of Photonic . Sciences. Barcelona, Spain. School on Quantum Nano- and Opto-Mechanics. July 8, 2016. Motivation. Optomechanics: unprecedented levels of control over interactions between motion and light. Luminous:. an object that emits/produces its own light (. eg. . sun). Non-luminous:. an object that do not produce its own light and is visible due to reflected light (. eg. . a tree). Sources of light. Module. Alireza . Etesami. University of Memphis. 2017. Reference: http://www.ide.titech.ac.jp/~takahak/pub/ORAN/EAMlecture.pdf. Initial position and velocities. Potential energy. Lennard-Jones (LJ). Lecture Presentation. Classifying Solids Based on Bonds. Metallic solids. are held together by a “sea” of collectively shared electrons.. Ionic solids. are sets of cations and anions mutually attracted to one another.. Atoms are composed of protons, neutrons and electrons. These subatomic particles are charged….. Atoms make elements… Elements can’t be broken down into anything simpler. . Examples:. Carbon= C. Camera Camera window Half mirror Light irradiationOptical axis of the camera lensStructual diagram Image when mountedon the Light Unit Application ExamplesInspecting electronic parts on the PCB Imagin gases. sand, snow, or grain (granular materials). FLUIDS .  . STUFF THAT FLOWS. FLUIDS. 1. States of Matter. Comes in three states – solid, liquid, gas. So far we have only dealt with . solid.