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Course Review Read your Project Reports Review the Studio and Lecture Quizzes What did you do, how did you do any calculations, what units were involved and what were the conclusions 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 New Technology Who developed major technology Roughly when What is the application of this technology 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 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 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. 1 kilowatt = 1 kilo-joule / 1 second 1 kW = 1 kJ / s 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 1kWh = 1kW x 1h = 3,600 kJ 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! The Law of Entropy *The natural processes lead to increase in disorder *Natural processes are irreversible. 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 TIME, MASS and LENGTH Time Mass Fundamental unit is the second (USA and SI) Now measured by frequency of light 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 WEEK 3 – MEASUREMENT WHEN NO DIRECT COMPARISON IS POSSIBLE Measurements when you can’t do a direct comparison with a standard Project 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 Indirect Measurement Rule height Ruler distance = Object height Object distance SCIENTIFIC NOTATION LARGE NUMBERS 2 significant figures 390,000,000,000,000,000,000,000 can be written as and small numbers 3.9 x 1023 3 significant figures 0.000000960 can be written as 9.60 x 10 -7 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 All Things Known to a PHY107 Student Gold Bronze Iron and Steel Ceramics Plastics Composites Aerogels Superconductors WEEK 5 – CHOOSING MATERIALS Project Effect of load, length and thickness Lecture – properties of elastic cords 4 Internal structure crystals Stress, strain, elastic constant Deformation •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 Graph of stress versus strain 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 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 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. WEEK 7 – USING LIGHT Project – images and objects with lenses Magnification, distances and sizes Image properties Plane mirrors Focused image with a lens Image Formed by the Eye 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 Color Addition Light Sources Color Subtraction Paints and Filters 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 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 Lecture on electrostatic charge 8 Setting up circuits How a battery works Cathode(-) Anode(+) Electrolyte Positive ions Insulating layer forms on anode 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(+) How to Measure Current and Voltage Connectingwires Ammeter Copper electrode Zinc electrode A Resistor Voltmeter 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 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 First Transistor (1947, John Bardeen, William Shockley, Walter Brattain at Bell Labs) 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 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 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 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. In the beginning- Charles Duryea – 1895 Ransom Olds – 1901 Henry Ford – 1903 1908 the Model T • $360 vs $5000 • 15 million by 1927 The Secrets of Flight Birds Kites and Gliders Balloons and dirigibles Propeller Driven Planes, Wright bros. Jet Driven Planes Helicopters How a Balloon Works WEEK 13 – ROCKETS and FLOTATION Project Archimedes principal Reduction in weight when submerged Lecture – Flotation 12 Rockets and rocket propulsion Balloons and dirigibles Buoyancy-Archimede’s principle A submerged object is pushed up with a force equal to the weight of the water displaced Newton’s Third Law of Motion Newton’s Third Law of Motion: For every action there is an equal and opposite reaction Rocket Mechanisms