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Course Review

Course Review. Read your Project Reports What did you do, how did you do any calculations, what units were involved and what were the conclusions Review the Studio and Lecture Quizzes Make sure you know how the answer was obtained. If it was conceptual be sure you understand the concept

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Course Review

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  1. Course Review • Read your Project Reports • What did you do, how did you do any calculations, what units were involved and what were the conclusions • Review the Studio and Lecture Quizzes • Make sure you know how the answer was obtained. If it was conceptual be sure you understand the concept • Reread the article references • See the syllabus for the instruction given in the studio. This is important

  2. New Technology • Who developed major technology • Roughly when • What is the application of this technology

  3. WEEK 1 – Conservation of Energy • Project on Solar Cells • Different forms of energy • Joules and watts • Hypothesis, efficiency, averages, graphs • Lecture • Cost of electricity • Energy conservation • Entropy

  4. Every time forces triggered by the stored energy make things move, we say that those forces do work. Energy is therefore the capacity for doing work in its broadest sense. Motion, heat, electricity, magnetism, light, can be made to do work, thus, they all embody different forms of energy

  5. What is kWh ? An appliance rated at 1 kilowatt (1 kilowatt = 1,000 watts) consumes one kilo-joule of energy (same as 1,000 joules) in every second.

  6. By the same token, the energy used by a one-kilowatt appliance in one hour (called 1 kilowatt-hour), that is, 1 kilo-joule / second x 3,600 seconds, is 3,600 kilo-joules Thus: 1 kilowatt-hour = 1 kilo-joule/second x 3,600 seconds = 3,600 kilo-joules

  7. Law of conservation of energy The conversions of energy are never fully effective because some of the energy becomes low grade (unusable) heat However Initial energy = useful energy resulted + energy wasted The total energy is conserved!

  8. The Law of Entropy *The natural processes lead to increase in disorder *Natural processes are irreversible.

  9. WEEK 2 – Direct comparison with a standard • Project on Measurement, area, volume mass and density • How to convert between units • suffixes to denote very large or very small numbers • significant figures • No lecture

  10. TIME, MASS and LENGTH • Time • Fundamental unit is the second (USA and SI) • Now measured by frequency of light • Mass • Fundamental unit is the kg (SI) or pound(USA) • Still a chunk of metal • Length • Fundamental unit is m (SI) or yard (USA) • Now measured by distance light travels

  11. WEEK 3 – MEASUREMENT WHEN NO DIRECT COMPARISON IS POSSIBLE • Project- Measurements when you can’t do a direct comparison with a standard • Using ratios to measure height or length • Measuring many items when one is too small • Scientific notation • Demonstration on finding the size of a molecule • Lecture – calibration standards

  12. Indirect Measurement Rule height = Object height Ruler distance Object distance

  13. SCIENTIFIC NOTATION • LARGE NUMBERS • and small numbers 0.000000960 can be written as 2 significant figures 390,000,000,000,000,000,000,000 can be written as 3.9 x 1023 3 significant figures 9.60 x 10 -7

  14. WEEK 4 – HEAT TRANSFER • Project – cooling a cup of liquid • Effect of cup material and starting temperature • Temperature scales, ways of losing heat • Lecture • Materials of the ages, gold, bronze, iron • Wood, glass, metals • Ceramics, plastics, composites, superconductors

  15. All Things Known to a PHY107 Student • Gold • Bronze • Iron and Steel • Ceramics • Plastics • Composites • Aerogels • Superconductors

  16. WEEK 5 – CHOOSING MATERIALS • Project – properties of elastic cords • Effect of load, length and thickness • Lecture 4 • Internal structure • crystals • Stress, strain, elastic constant • Deformation

  17. STRESS = force applied per unit area • STRAIN = change in length • original length • ELASTIC MODULUS = STRESS/STRAIN The stiffer the material, the less the length will change under same stress

  18. Graph of stress versus strain

  19. WEEK 6 – REFLECTION and REFRACTION • Project –properties of light • Names and locations of angles • Refractive index and Snell’s law • Total internal reflection • Speed of light changes with material • Lecture 5 • Properties of light, reflection, refraction, scattering • Human vision and correcting defects

  20. VISIBLE LIGHT • Small part of the electromagnetic spectrum • Travels in straight line in same medium • Can be reflected, refracted, scattered and absorbed • Nothing can move faster than light in a vacuum • Possesses energy

  21. We may think that radio waves are completely different physical objects or events than gamma-rays. They are produced in very different ways, and we detect them in different ways. But are they really different things? The answer is 'no'. Radio waves, visible light, X-rays, and all the other parts of the electromagnetic spectrum are fundamentally the same thing. They are all electromagnetic radiation.

  22. WEEK 7 – USING LIGHT • Project – images and objects with lenses • Magnification, distances and sizes • Image properties • Plane mirrors

  23. Focused image with a lens

  24. Image Formed by the Eye

  25. WEEK 8 – COLOR and WAVELENGTH • Project – colors, light sources and filters • Analysis of light, wavelengths, energy • Color addition and color subtraction • Use of spectrometer • Properties of laser light • Passing light through a prism • Lecture 7 • Color by addition, subtraction and mixing • Atoms as sources of light • Wave and particle description of light • Electrical circuits, series and parallel, batteries

  26. Color Addition LightSources Color Subtraction Paints and Filters

  27. Light from atoms • Light is made up of little • “packets of energy” called photons • When you have many photons they • behave as if they were a wave • The photons are emitted by atoms

  28. WEEK 9 – ELECTRICAL BATTERIES and CIRCUITS • Project – making and using batteries • Effect of different battery components • Parallel and series connections • Measuring voltage and current • Demonstrations on electrostatic charge • Lecture 8 • Setting up circuits

  29. How a battery works Cathode(-) Anode(+) Electrolyte Positive ions Insulating layer forms on anode

  30. CURRENT FLOW • Current is the flow of electrons • By convention we say positive current flows from the anode (+) to the cathode(-) • At the microscopic level electrons (negatively charged) move from the cathode(-) to the anode(+)

  31. How to Measure Current and Voltage

  32. WEEK 10 – ELECTRICITY and MAGNETISM • Project – electromagnet • Effect of voltage, # of turns • Demonstration of motors, generators and the relation between electricity and magnetism • Lecture 9 on different forms of electromagnetic radiation • Radio, radar, heat (IR), visible, UV, X-rays • applications

  33. WEEK 11 – ELECTRICAL CIRCUITS • Project • Ohms law • Resistance, voltage and current • Lecture 10 • Development and use of computers, ENIAC • Audion, transistor and integrated circuits • Binary communications

  34. FirstTransistor (1947, John Bardeen, William Shockley, Walter Brattain at Bell Labs)

  35. Binary Uses in Computer • Digital characters – ASCII code Stored as a byte (8 binary digits) Example: A = 01000001 • Arithmetic with digital Example: 01 + 10 = 11 which means 1 + 2 = 3 in decimal • Computer code Instruction, what to do, where to do it, which piece of data to use

  36. WEEK 12 – MOTION and TRANSPORT • Project • Constant speed and acceleration • Potential energy and kinetic energy • Gravity • Lecture 11 • History of automobiles and planes • Car engine cycle • Mechanics of flight and propulsion

  37. DEFINITIONS FOR USE WITH MOTION SPEED is how rapidly an object moves or changes its position. It is calculated by dividing how far an object moves by the time taken to move. Speed = (distance moved) / (time taken moving) Example. If a runner covers 400m in 50 s, the average speed is 400m / 50 s = 8 m/s ACCELERATION is how rapidly an object changes its SPEED (or VELOCITY) It is calculated by dividing the change in speed by the time taken to make that change. Acceleration = (change in speed) / (time taken to make that change) Example. A car accelerates from rest (speed=0 m/ s) to 28m/s in 7 s acceleration = (28 – 0) m/s / 7 s = 4 m/s per second = 4 m/s2 FORCE is what causes something to accelerate. If some object changes its speed it has accelerated and must have had a FORCE acting on it. The larger the mass of an object the smaller its acceleration for the same FORCE. NEWTONS Law states that force is the product of mass and acceleration. Force = mass x acceleration Example. A mass of 2 Kg changes its speed from 5 m/s to 25 m/s in 2 s. Acceleration = (25-5)m/s / 2s = 20m/s / 2s = 10 m/s per s or 10 m/s2 Force = 2 kg x 10 m/s2 = 20 Newtons

  38. GRAVITY is the FORCE by which an object is attracted to the center of the Earth It is calculated by multiplying the mass by the gravitational constant(10 m/s2). Force (Newtons) = mass (in Kg) x 10 [More precisely the Gravitational constant is 9.81 m/s2 , rather than 10 m/ s2] POTENTIAL ENERGY(PE) is energy possessed because of height. PE can also occur by storing energy in springs, electric fields and magnetic fields. PE(in Joules) = mass(in Kg) x gravitational constant x change in height(in m) Example. Gain in PE by lifting 5 Kg up 2 meters is 5 x 10 x 2 Joules = 100 Joules KINETIC ENERGY (KE) is energy possessed because of the movement of an object. KE(Joules) = ½ x mass(in Kg) x (speed)2 when speed is in m/s Example. A mass of 5 Kg with a speed of 4 m/s has a KE = ½ x 5 x 4 x 4 = 40 Joules MECHANICAL ENERGY is energy associated with motion and position. It is calculated by adding together the kinetic energy and the potential energy.

  39. In the beginning-- • Charles Duryea – 1895 • Ransom Olds – 1901 • Henry Ford – 1903 • 1908 the Model T • $360 vs $5000 • 15 million by 1927

  40. The Secrets of Flight • Birds • Kites and Gliders • Balloons and dirigibles • Propeller Driven Planes, Wright bros. • Jet Driven Planes • Helicopters

  41. How a Balloon Works

  42. WEEK 13 – ROCKETS and FLOTATION • Project – Flotation • Archimedes principal • Reduction in weight when submerged • Lecture 12 • Rockets and rocket propulsion • Balloons and dirigibles

  43. Buoyancy-Archimede’s principle A submerged object is pushed up with a force equal to the weight of the water displaced

  44. Newton’s Third Law of Motion Newton’s Third Law of Motion: For every action there is an equal and opposite reaction

  45. RocketMechanisms

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