Superconductors & Related Achievements Concepts of Nobel Prize in Physics through Concept Mapping Contents Chapter 1 : Introduction 1.1 What is Learning? 1.2 Concept Mapping 1.3 Concept Mapping in Present Context Chapter 2 : Concepts of Nobel Laureates through Concept Mapping 2.1 Matter at Low Temperature : Concepts of Nobel Prize in Physics for the year 1913 2.1.1. Introduction 2.1.2. Achievement of Low Temperatures by Kamerlingh Onnes 2.1.3. Effects of Low Temperature 2.1.4. Superconductivity 2.2 The Theory of Liquid Helium : Concepts of Nobel Prize in Physics for the year 1962 2.2.1. Introduction 2.2.2. New State of Liquid Helium 2.2.3. Properties of Superfluid according to Landau 2.2.4. Properties of Helium-3 2.3 Theory of Superconductivity : Concepts of Nobel Prize in Physics for the year 1972 2.3.1. Introduction 2.3.2. Principle of Superconductivity 2.3.3. Superconductivity due to Cooper Pairs 2.3.4. Applications of Superconductors 2.4 Tunnelling in Superconductors : Concepts of Nobel Prize in Physics for the year 1973 2.4.1. Introduction 2.4.2. Laws of Modern Physics 2.4.3. Initial Discovery of Tunnelling Effect 2.4.4. Superconductor on the basis of Tunnelling Effect 2.4.5. Josephson Effect 2.4.6. Applications of Tunnelling Effect 2.4.7. Applications of Josephson Effect 2.5 Helium II - The Superfluid : Concepts of Nobel Prize in Physics for the year 1978 2.5.1. Introduction 2.5.2. Helium II - The Superfluid 2.6 High Temperature Superconductivity - Concept of Nobel Prize in Physics for the year 1987 2.6.1. Introduction 2.6.2. Meissner Effect 2.6.3. High Temperature Superconductor 2.7 Superfluidity in Helium-3 : Concept of Nobel Prize in Physics for the year 1996 2.7.1. Introduction 2.7.2. Quantum Fluids 2.7.3. Isotopes of Helium 2.7.4. Properties of Helium-4 2.7.5. Properties of Helium-3 - Under Normal Conditions 2.7.6. Properties of Helium-3 - Under Special Conditions 7.7. Phase Transition in Helium-3 2.7.8. Superfluidity in Helium-3 2.7.9. Properties of Superfluidity in Helium-3 2.7.10. Application of Superfluidity in Helium-3 2.8 Development of Methods to Cool and Trap Atoms with Laser Light : Concepts of Nobel Prize in Physics for the year 1997 2.8.1. Introduction 2.8.2. Principle of Optical Molasses 2.8.3. Slowing down Atoms with Photons 2.8.4. Doppler Cooling and Optical Molasses 2.8.5. Magneto Optical Trap 2.8.6. Zeeman Slower 2.8.7. Optical Lattice 2.8.8. Formation of Dark State 2.8.9. Velocity Distribution at Recoil Temperature 2.8.10. Applications Round the Corner 2.9 Bose Einstein Condensation in Dilute Gases : Concepts of Nobel Prize in Physics for the year 2001 2.9.1. Introduction 2.9.2. Nobel Laureates of 2001 2.9.3. Types of Particles 2.9.4. New State of Matter - Bose Einstein Condensation 2.9.5. Super Atom 2.9.6. Magneto Optical Trap to exceed Doppler Limit 2.9.7. Evaporative Cooling of Alkali Atoms 2.9.8. Reality of Bose Einstein Condensation (BEC) 2.9.9. Prospects of Bose Einstein Condensation Chapter 3 : Conclusion 3.1 Effectiveness of Concept Mapping CHAPTER 1 INTRODUCTION 1.1 What is learning? Every branch of human activity has made rapid progress like discovery of Windows XP, Cloning in animal and human physiology and embracing technology in various fields like banking, communication, industries, education etc.The changes in many fields are reflected in education, where, the knowledge is not merely imparted, but makes the learner apply it in various situations. Knowledge in our minds is specifically defined as a hierarchical structure of concepts, in which inclusive concepts occupy a portion at the apex of the structure and subsume progressively less inclusive and more highly differential subconcepts and factual data. Acquisition of knowledge is the learning of organized information. According to Ausubel, the most important single factor influencing learning is what the learner already knows. Thus meaningful learning results when a person consciously and explicitely ties new knowledge to relevant concepts they already possess. Rote learning on the other hand results, when new knowledge is arbitrarily incorporated into the cognitive structure. That is the material is not linked with existing concepts in cognitive structure and form ‘discrete and isolated traces’. Knowledge in various fields is acquired to enrich ones life by making use of the technological advances. Science Education will generally impart knowledge in such a way that students will learn what they are taught and transfer what they have learnt to a more complex situation. Since superconductors and related achievements have wide range of applications in various fields, I thought a better understanding of above concepts would be more useful. Hence in this book, the concepts of superconductors and related achievements ( concepts of Nobel Laureates of Physics ) are explained through Concept Mapping, a strategy which enhances meaningful learning. 1.2 Concept Mapping The Concept Map is a device for representing the conceptual structures of a subject discipline in a two dimensional form. It is a technique for representing knowledge in graphs. Knowledge graphs are networks of concepts. Networks consist of nodes and links. Nodes represent concepts and links represent the relations between concepts. Concept Maps organize knowledge into a hierarchical structure in which subordinate concepts are subsumed under superordinate concepts. Rote learning would be just a series of propositions that are memorized, but not related to each other. With mapping, new concepts and propositions are connected into a whole existing relevant framework. Therefore, a Concept Map may be defined as a schematic device for representing a set of meanings embedded in a framework of propositions which enhances meaningful learning. 1.3 Concept Mapping in Present Context In this book, the concepts of superconductors and related achievements for which Nobel Prizes have been awarded are expressed through Concept Maps. Simple explanations precede the Concept Maps and I am sure the reader will enjoy going through the book and get enriched in knowledge. CHAPTER 2 Concepts of Nobel Laureates through Concept Mapping 2.1 Matter at Low Temperature : Concepts of Nobel Prize in Physics for 1913 2.1.1 Introduction The Dutch physicist Heike Kamerlingh Onnes was awarded the Nobel Prize in physics for 1913 for his investigations on the properties of matter at low temperatures which led to the production of liquid helium. Initially he was interested in Vanderwaal's theory of gases, according to which all gases behave in the same way when the units of pressure, temperature and volume are adapted to account for weak forces of attraction between molecules. By studying the gases at low temperatures, Kamerlingh Onnes believed that important information could be obtained to verify the conformity of substances. The following Concept Maps would illustrate how he investigated the properties of substances at low temperatures, and paved way for the discovery of superconductor. 2.1.2. Achievement of Low Temperatures by Kamerlingh Onnes The name of the scientist, Kamerlingh Onnes who has achieved low temperatures, occupies the apex of the Concept Map 1. The first branch deals with his field of specialization, cryogenics, to study the properties of substances at low temperatures.The second branch indicates that hydrogen was liquefied in 1906 and the third branch denotes that helium was liquefied in 1901 at 4 K. The last branch deals with low temperatures achieved by him at 1.38 K and 1.04 K respectively using liquid helium. Hence the most general concept, the name of the scientist, is followed by progressively more specific and less inclusive concepts arranged in hierarchical manner. 2.1.3. Effects of Low Temperature The most general concept, the name of the scientist ( Kamerlingh Onnes ) is at the apex of the Concept Map 2. The first branch deals with his achievement, low temperature for studying properties of substances. The next branch indicates that random motion of molecules will be minimum at low temperature. The third branch indicates the investigations of various fields like absorption spectra of elements, phosphorescence of various compounds, viscosity of liquefied gases and magnetic properties of substances. 2.1.4. Superconductivity In the third Concept Map, the first segment deals with the discovery of superconductivity, where electrical resistance of certain metals vanishes at low temperature. The second segment mentions the theory, which explains superconductivity. The third segment mentions the Nobel Prize won by the scientist for his investigation on properties of matter at low temperature. The last segment mentions the applications of superconductivity to various fields. 2.2 The Theory of Liquid Helium : Concepts of Nobel Prize in Physics for the Year 1962 2.2.1 Introduction Lev Davidovich Landau was awarded the Nobel Prize in Physics for 1962 for his investigtion on condensed matter i.e. matter in the solid and liquid state. In 1937 he joined the Institute for Physical Problems in Moscow run by famous physicist Kapitsa. Together they performed interesting experiments on liquid helium.They found that natural helium when cooled to 2 degrees above 0 K exhibited strange properties. The Concept Maps presented in this section illustrate the New State of Matter, its Properties, and Isotope of Helium (Helium-3) and its Properties at very Low Temperatures. His theories of liquid helium are an achievement of great and profound importance. 2.2.2 New State of Liquid Helium The scientist Kapitsa liquefied and cooled natural helium to about 4 degrees above 0 K. He found that when it was further cooled to about 2 degrees, it was transformed into a new state known as superfluid, having strange properties as it can flow through fine capillaries and slits not done by other liquids.