Waves, the Atom and Optics

1. Waves, the Atom and Optics Carlos Silva October 14th 2009

2. WAVES

3. Vibrations • Definition Mechanical oscillation around an equilibrium point • Mass-spring system oscillation • Beam • Drum • Types of vibration Free • When we apply a force and then let the system vibrate with its natural frequency Forced • When we apply an alternated force (earthquake) • Systems vibrate due to the “Momentum Conservation” law

4. Period, Frequency and Amplitude • Period (s) Interval of time measured in seconds that takes to repeat the vibration (T) • Frequency (Hz=s-1) Number of events/repetitions per second (f) • Wave length (m) Distance between repeating units • Amplitude Maximum variation during vibration (displacement, angle) • Vibrations are usually sinusoidal This happens when the applied force is linear This only happens for “small” amplitudes This is called harmonic motion

5. Natural Frequency and Resonance Natural frequency Property of every system Multiple modes of vibration (harmonics) Multiples of the natural frequency Resonance Tendency to oscillate at maximum amplitude at natural frequency A force applied at the same frequency is providing energy to the system at a rate that is higher than the damping Damping Mechanism of energy dissipation of vibration Vibration modes Damping Takoma bridge: www.youtube.com/watch?v=3mclp9QmCGs

6. Waves • Definition Type of disturbance that propagates through time and space Wave is a thing that transports energy and its not matter (doesn't obey Newton's laws) They differ from matter in three ways: • Superposition – two waves can be at the same place at the same time • They transport energy, not the medium (the medium vibrates!) • Wave velocity depends on the medium of propagation (does not depend on the force – put energy into a wave “only” affects its amplitude) • Types of wave Sound Light Water

7. Reflection, Transmission, Refraction and Absorption • Reflection Change of a wave direction at an interface between two different media so that the wave returns into the media where it was originated • Transmission Wave changes the propagation mean • Refraction Change of a wave velocity (and direction) when it changes media • Absorption Change of the wave amplitude by the dissipation of its energy

8. Waves: Energy, wavelength, frequency

9. Light as matter, matter as wave Wave-particle duality concept that all matter and energy exhibits both wave-like and particle-like properties • Corpuscles are light matter • Nuclear particles that behaves like wave

10. The ATOM

11. Atoms Definition Smallest unit of an element that retains its chemical properties Greek átomos that stands for indivisible Nucleus Protons (+) Neutrons Electrons cloud Electrons(-) Special orbits They gain or loose energy while jumping from orbits Number of protons= number of electrons Bohr hydrogen (H) model Oxygen (O) atom

12. Molecule Molecule Stable and electrical neutral combination of atoms Water 90% of the matter in Earth is H2O Carbon Abundant Affinity to link to smaller atoms Hydrocarbon Compound of Hydrogen and Carbon Energy sources Carbon Dioxide (CO2 ) water (H2O) propane(C3H8) Carbon Dioxide(CO2)

13. Isotopes • Isotopes are different types of atoms of the same chemical element, each having a different number of neutrons • Deuterium • Hydron atom + 1 neutron • Tritium • Hydron atom + 2 neutron

14. Ions • Atom or molecule where the total number of electrons is not equal to the total number of protons • Anion • More electrons than protons • Cation • Less electrons than protons

15. Quantum physics Heisenberg Principle locating a particle in a small region of space makes the momentum of the particle uncertain; and conversely, that measuring the momentum of a particle precisely makes the position uncertain. Quantum mechanics Explain motion of nuclear particles (Classical mechanics fail) Matter as wave Quantum hydrogen model

16. Periodic table

17. Nuclear Plants Use nuclear energy to produce electricity using stem cycle Like thermal plants using coal, oil, gas 4 generations of reactors III – Advanced Boiling Water Reactor (GE) IV - Very High Temperature Reactor Calder Hall UK (1954) Waste Flacks Yucca Mountain Nevada, US Generation IV

18. Fission Definition splitting of the nucleus of an atom into parts forming neutrons and photons (gamma ray) Radiation Atoms Loss of energy Alpha, beta or gamma radiation Uranium reaction

19. Fusion Definition multiple- like charged atomic nuclei join together to form a heavier nucleus Proton-proton chain reaction Converts hydrogen into helium Takes 109 years to occur at start’s core temperature Nuclear Power with fusion In 1997, JET produced 10MW for 0.5s ITER in 2018 will produce 500MW for 1000s Nuclear Energy (SI) Electro-Volt: 1 eV = 1.602 176 53(14)×10−19 J JET tokamac Deuterium-tritium reaction

20. Hydrogen Fuel Natural state (H2) 75% of matter (mass) or 90% of mater in terms of number of atoms Energy carrier Production Water Electrolysis: separate molecules through electricity (30%-40% efficiency) Storage Compressed or liquid Fuel Fuel Cells Adapted gasoline motor Water electrolysis Filling station (Germany) Hydrogen cell Toyota FCHV

21. OPTICS

22. The nature of light • Light characteristics: Electromagnetic radiation Light travels from one point to another It travels in vacuum (unlike sound, which is an air pressure) Light transports energy When we absorb light, it is transformed in heat • Visible Light Radiation whose wavelength is 380-750x10-9m Light refraction (prisma) Light refraction (water)

23. Reflection, refraction Reflection Incidence angle=reflection angle Refraction Changes speed and angle of light Diffraction Light propagation over small open obstacles and openings Mirror Reflection Refraction Lens

24. Thermal solar panels Flat plate Evacuated tube Heating through reflection Solar power plant Almeria, Spain Installation diagram

25. Photovoltaic panels PN junction Photovoltaic panel (PV) Equivalent circuit