|1.||Monday, Nov. 16 -- class list, syllabus, labs|
|Macroscopic and microscopic approaches to
Zeroth law of thermodynamics
Various thermometers - metal rod, liquid in open container, liquid in closed container, wire or thermister
Temperature scales - Fahrenheit, Celsius, Kelvin - and conversions between them
Triple point of water - 273.16 K at a vapor pressure of 4.58 torr
Thermal expansion of solids in one and two dimensions
Problem 13.18: Calculate the change of area of a rectangular plate when it is heated and its temperature increases by ΔT.
Bimetallic strips, Demos: steel/brass strip heated in a flame; ball and ring
|2.||Wednesday, Nov. 18|
|Thermal expansion of solids in three dimensions -
equation for the change of volume. Table 13-1 on p. 358. |
Video 1 - "Thermal Expansion: Liquids", Video 2 - "Phase Change Expansion: Ice Bomb"
Video 3 - "Thermal Expansion: Breaking Rod", Video 4 - "Linear Expansion: Determination of Alpha"
Ideal gases - Boyle's law, Gay-Lussac's law, Charles' law Periodic Table
Animation-1 and Animation-2 illustrate these laws
Ideal gas law (Equation of State of an Ideal Gas)
Universal gas constant: R = 8.314 J/mol-K = 0.08206 liter-atm/mol-K
Avogadro's number: NA = 6.022 x 1023 molecules/mol
Boltzmann's constant: k = R/NA = 1.38 x 10-23 J/K
Kinetic Theory of Gases, rms (root mean square) velocity, ave. KE per mole, ave. KE per molecule
|3.||Friday, Nov. 20|
|Speed distribution of molecules in a gas - physlet
- After it comes up and runs for awhile, click on "Average" and watch
the graph evolve.
Graph of distribution of velocities in a gas (Nv vs. v). Shows vrms, vave and vp (most probable).
Video 5 - "Kinetic Model: Temperature Effects on Gases", Video 6 - "Cryogenics: Organic Materials"
Review (Jacques) Charles law ...
Demo - cool things with liquid nitrogen: balloon, banana, plant leaves, ...
Video 7 - "Induced Phase Change: Solid N2"
Evaporation... Maxwell velocity distribution, demo - glass of water, explanation via the graph...
Relative humidity and vapor pressure
Video 8 - "Cryophorous: Cooling by Evaporation", Video 9 - "Induced Phase Change: Boiling by Cooling"
Video 10 - "Condensation: Formation of a Cloud"
Saturated vapor pressure (SVP), relative humidity (RH), partial pressure (PP), RH = 100*PP/SVP
Demo - humidity gauge
Fog, smog, vog (volcanic gas + fog) - CO2 and sulfur
Problems from Chapter 13. Table 13-3
|4.||Monday, Nov. 23 - Chapter 14 - Heat - Q4|
|Definitions: calorie, kilocalorie (= food
Conversions: 1 kcal = 4186 J, 1 Btu = 252 cal
Mechanical equivalent of heat = J = 4.186 J/cal = W/Q (Joule's law)
heat absorbed = Q = m c ΔT, where m = mass, c = specific heat, ΔT = temperature change, Table 14-1, p. 387
heat gained = heat lost (conservation of energy)
latent heat of fusion of water = LF = 79.7 cal/g (at 0oC)
latent heat of vaporization of water = LV = 539 cal/g (at 100oC)
If a substance changes phase: heat gained (or lost) = mass x latent heat, Q = m L
Problem: Drop ice cubes into some water. Calculate the final temperature.
heat of combustion = heat given off in burning
heat conduction - heat transfer occurs by molecular collisions with no net movement of the molecules
rate of heat flow = H = Q/Δt = k A ΔT / l where k = thermal conductivity, A = area, l = thickness, Table 14-4, p. 396
Demo - touch metal, then an insulator (like wood) at the same temperature - which feels colder?
Video 11 - "Thermal Conduction: Propagation in a Metal Rod", Video 12 - "Thermal Conductivity: A Two Rod Combination"
|5.||Wednesday, Nov. 25 - Q5|
| R-value = R
= l / k, rate of
heat flow = H = Q / Δt = A
ΔT / R,
Table 14-5, p. 397
Review - various forms of energy ... (10 listed in class)
Demo - happy ball, sad ball, energy conservation; push book along the table
Heat is another form of energy: Q = mcΔT, Q = mL
Three types of heat transfer: conduction, convection, radiation
Convection: when "hot" molecules are physically transported from one region to another. Convection may be natural - caused by variations of fluid density in a gravity field, or forced - caused by a fan.
Rate of heat flow = Q / Δt = h A ΔT
Wind chill temperature index - chart (National Weather Service)
Demo - Bunsen burner shadow... variation of air density
Video 13 - "Thermal Convection: Induced Fluid Flow", Video 14 - "Thermal Convection: Projection of Currents".
Radiation - heat is transferred from one molecule to another by electromagnetic waves.
Thermograms - Fig. 14-14, p. 402, human bodies
Video 15 - "Thermal Radiation: Transmission Using Parabolic Mirrors", Video 16 - "Thermal Radiation: Black Body Effects", Video 17 - "Thermal Radiation: Leslie's Cube".
Problem 14-44 on page 406.
|6.||Monday, Nov. 30 - Chapter 15. The Laws of Thermodynamics|
| The 1st Law: All
the heat (energy) added to a closed system (constant mass) can be
accounted for as mechanical work, an increase in internal energy, or
both. In equation form: ΔU = Q
Various processes: isothermal, isometric, isobaric, adiabatic
Internal energy of an ideal gas: U = 3/2 nRT
Work = area under the PV curve
For an adiabatic process, PV γ = constant
Video 18 - "Pressure and Temperature: Piston in a Cylinder".
Human metabolism - conversion of internal energy (food - chemical energy) by an organism into other forms of energy:
work, heat, waste products - metabolic rate (Table 15-5 on p. 415) varies like mass3/4
|7.||Wednesday, Dec. 2 - Q7|
| Heat engines - a device for obtaining mechanical
work out of the heat energy of fuel - 2-stroke engine
(lawn mower, ...) |
4 stroke gasoline engine (internal combustion) - Figure 15-13, p. 417
Two-cylinder four stroke motor
Flash Physics Animations: 2 stroke engine, 4 stroke engine
2nd Law of Thermodynamics
Kelvin statement: It is impossible to construct an engine that, working in a cycle, has no effect other than the
extraction of heat from a reservoir and the performance of an equal amount of work.
Clausius statement: It is impossible to construct an engine that, working in a cycle, has no effect other than the
transfer of heat from a colder to a hotter body.
Coefficient of performance
Problems from Chapter 14.
|8.||Friday, Dec. 4|
Law of Thermo, ΔU = Q -
W, Drawings for a Real Heat Engine and a
|9.||Wednesday, Dec. 9 - Chapter 16 - Electric Charge and Electric Field|
| Video 20
- "Electrostatics - Interaction of Charge", Video
21 - "Distribution of Charge on a Conductor", |
Video 22 - "Induction of Charge".
Design and operation of an electroscope.
Nine basic experimental results:
|10.||Friday, Dec. 11 - Q10|
| The Triboelectric
Series - shows how strongly various materials hang on to
their electrons when you rub them together. |
List of items from Wednesday plus a few others, in order from most positive to most negative:
Superposition Principle - For multiple charges, the vector force on each one is the sum of the vector forces
from all the others.
Charge and mass of the (1) electron, (2) neutron, and (3) proton
Analogy: force between masses - force between charges
Definition of an electric field, E = Fe q = k Q/r2
Technique for tracing electric field lines
Result: electric field lines always originate on positive charges and end on negative charges. Fig. 16-30, Fig. 16-31
Computer drawings - EM Field program - 3D sources - electric field vectors (E) and electric field lines
|11.||Monday, Dec. 14 - Went over Test 1|
Video 23 - "Corona Discharge
- Electronic Precipitator", Video
24 - "Electric Fields: Mapping of Force
|Wednesday, Dec. 16|
| Potential difference - gravitational and electrical |
Electric potential difference, ΔV
The "ground symbol", definition of voltage: potential difference with respect to ground.
Over short distances, points connected by a (metal) wire are at the same potential (ΔV = 0).
All points on the outside surface of a conductor are at the same potential.
An equipotential surface is one for which all points are at the same potential.
Around a point charge q, the equipotential surfaces are spherical shells. V = kq/r where r = radius of the shell.
Equipotential surfaces are everywhere perpendicular to the lines of force (i.e. the electric field lines).
Computer drawings - EM Field program - 3D sources - electric potential, V Fig. 17-6, Fig. 17-7
For a charge q moving through a potential difference V, the change of potential energy is ΔPE = qV.
Definition: 1 electron volt = (electron charge) (1 volt), That is, 1 eV = 1.60 x 10-19 C x 1V = 1.60 x 10-19 J.
Corona discharge - discharge of a conductor into the air producing a visible glow or spark. Demo - high voltage source
Problems from Chapter 16.
|Friday, Dec. 18 - Q13|
Capacitors - Any two conductors separated from one another by an insulator is a capacitor.
|14.||Monday, Jan. 11|
Demo - high voltage (1000 V) applied to 5
capacitors in parallel (26 mF) - BOOM! - release of 13 J
Video 29 - "Energy Stored in a Capacitor"
Explanation of a cathode ray tube (CRT) - oscilloscope - Fig. 17-20 on p. 486, TV - Fig. 17-21.
Chapter 18 - Electric Currents
Explanation of a zinc-carbon battery
Definition of emf (electromotive force) - a source of emf is any device that will transform nonelectrical energy into electrical energy. e.g. battery, electric generator, solar cell
Video 30 - "Operation of a Battery"
Definition - electric current = I = ΔQ / Δt , unit for current: ampere (A). 1 A = 1 C/s
Analogy: fluid flow - electric circuit
Definition - the direction of conventional current flow is opposite to the direction the electrons flow
Drift velocity - it is extremely slow - typically about 1 m per 5.5 hours!
|Wednesday, Jan. 13|
(Georg) Ohm's Law -
resistance = voltage / current
|Friday, Jan. 15 - Q16|
- electrocuting a hot dog. So what is in hot dogs to make them
behave like semiconductors?
Superconductors - materials for which the resistivity ρ becomes zero as you lower the temperature through the phase transition temperature, Tc. Graph of R vs. T. Use a 4-point connection to avoid measuring contact resistance - demo
1. In 1911 in mercury by Kamerlingh-Onnes (Tc = 4.15 K)
2. In 1986 in La2CuO4 by Karl Muller and George Bednorz (who received the Nobel prize) (Tc = 35 K)
3. In 1987 in YBa2Cu3O7 (this is also called the "1-2-3 superconductor") by two groups (Tc = 92 K).
Demo - magnetic levitation with a 1-2-3 disk, a styrofoam boat, liquid nitrogen (T = 77 K) and a small magnet.
Video 32 - "Superconductivity: Zero Resistance and the Meissner Effect"
Theory of superconductivity - Hyperphysics - Georgia State University - C. R. Nave
Superconductors Web site - includes the history
1. At Fermilab magnetic windings (wires) are cooled with liquid helium (4.2 K) so the wires are below Tc resulting in
a tremendous savings in electricity (practically no "Joule heating"). The magnetic field of each 7-meter tubular
magnet is 4.5 tesla.
2. "maglev" (magnetic leviation) trains in Japan, Germany and China (Shanghai).
3. Superconducting magnet in Science 114 - part of the 400-MHz NMR (nuclear magnetic resonance) equipment. The
outer part is cooled by liquid nitrogen (77 K). The inner part is cooled by liquid helium (4.2 K). The magnetic field is
very strong (9.7 tesla) and is well regulated. This field is created by means of a solenoid (coil of wire). The wire
consists of very fine strands of superconducting niobium-titanium clad in copper. This is a Type II superconductor
with a critical temperature Tc = 10 K. NMR slides taken Jan. 20, 2004. NMR cutaways - JEOL
Unassigned problem - 18-9 on page 516.
|Wednesday, Jan. 20|
Chapter 19. DC Circuits
Kirchhoff's First (junction) Rule: The algebraic sum of the currents at any junction in a circuit is zero.
Kirchhoff's Second (loop) Rule: The algebraic sum of the changes in potential around any closed path in a circuit is zero.
Potential difference in a circuit - resistors, batteries
Demo: 6V battery, (variable) resistance box, two DMM's, wires - measure E and I, calculate R
Demo: add a second resistance box. Results: spreadsheet with graph
Example of using Kirchhoff's rules - two batteries, 7 resistors
Internal battery resistance (ranges from 0.05 ohms for new batteries to 100 ohms for old ones)
Resistors in series: Rs = R1 + R2 + R3
Resistors in parallel: 1/Rp = 1/R1 + 1/R2 + 1/R3
Demo: three resistors (33 ohm, 56 ohm and 100 ohm) placed in series and then parallel - measure R
|Friday, Jan. 22|
Video 33 - "Series and Parallel Circuits"
"Use of a Working Hypothesis" - series and parallel
Combining emfs in series and in parallel
Example of using Kirchhoff's rules - 3 equations in 3 unknowns
|19.||Monday, Jan. 25|
Chapter 20 - Magnetism
A magnetic field is caused by moving charges - Lorentz force equation - Fm = q v x B
Diagram showing magnetic field lines for several kinds of magnets - bar, neodynium, horseshoe
Demo - zinc coated iron fillings on overhead, magnetic field lines - applet
Video 34 - "Mapping Magnetic Field Lines"
(magnetic declination) = (direction of true north) - (direction of magnetic north) | map (Figure 3)
Dip needle - here in the Quad Cities we are currently at about 55 degrees and the (magnetic declination) = 2oE.
Cross product of two vectors A and B: C = A x B, three ways to find the direction of C ...
Magnitude of Fm = q v B sin θ
Video 35 - "Forces on an Electron Beam"
|Wednesday, Jan. 27|
Demo: Three glass tubes have a high
voltage applied creating a plasma (bluish glow due to ionization of air
molecules), deflect the beam with a magnetic field, round tube shows some
fluorescence (green) when electrons hit the glass
|Friday, Jan. 29|
Examples: the Tevatron at Fermilab
and the Large
Hadron Collider at CERN
v not parallel to B: spiral path. Occurs in nature around BEarth - produces the aurora borealis
photos of Nov. 5, 2001 | SpaceWeather.com | Aurorawebcam.com
Hall effect, Hall voltage = V = vd B l Demo: digital Tesla meter, magnet...
Torque on a current loop (suspended vertically) in a magnetic field, τ = N I A B sin θ
How does a DC electric motor work?
Demo: function generator - speaker - square wave - low frequency
How does a loudspeaker work? Fig. 20-38
|22.||Monday, Feb. 1 Q22|
Chapter 21. Electromagnetic Induction and
Faraday's Law - AC Circuits
|Wednesday, Feb. 3|
induced current in a circuit
Applications: recording and playback heads in tape recorders, VCRs, floppy disks, hard disks
Electric generator (dynamo), motor - electrical to mechanical, generator - mechanical to electrical
Fig. 21-15 and Fig. 21-17. An ac generator.
Generator theory: ξ = N B A ω sin (ω t), ω = the angular frequency (in rad/s), ω = 2 π f, f = frequency in Hz.
Demo: generator #1 - incandescent bulb (digital multimeter to measure ac volts), flicker bulb
Demo: generator #2 - (a) nothing - turns easily, (b) flashlight bulb, (c) a wire near a compass, (d) wrap the wire around the compass, what if there were several turns? (e) thermoelectric heat pump - Peltier (pelt-ee-yay) effect - turn crank one way (hot) and then the other (cold). This is how the Coleman thermoelectric heat pump works.
Ring launcher - various rings - demo
|Friday, Feb. 5|
Solenoid doorbell (p. 567) Fig. 20-27
Demo: run a DC generator backwards - its a DC motor!
Alternator - demo - show an actual automobile alternator
Transformers - Java applet - show examples - Fig. 21-25.
Video 38 - "Voltage Transformer"
Eddy currents are circular currents induced in the plane of a metal plate when passing through a changing magnetic field.
Demo: aluminum plate on a wooden pendulum swinging through a strong magnetic field
Video 39 - "Eddy Currents: Force Acting on a Moving Conductor"
Inductance, L Demo: various inductors (coils),
measure with a digital LRC meter
From experiment, induced emf = ξ = - L ΔI / Δt
Combine with Faraday's law to get L = NBA / I
For a solenoid: B = μ0n I so L = μ0N2A / l
Energy (in joules) stored in a coil (inductor), i.e. in a magnetic field: U = ½ L I 2
LR circuit (battery, switch, inductor and resistor in series)
Equation for I ..., time constant = τ = L / R
|25.||Monday, Feb. 8|
- all in parallel: function generator, resistor (100
speaker (8 Ω),
DMM (ac volts), oscilloscope
Results: DMM (digital multimeter) reads Vrms = 0.707 volts
The oscilloscope displays the sine wave with amplitude = V0 = 1.00 volts
(average power delivered) = Pave = Irms2 R = Vrms Irms
Chapter 21. Sections 12-14.
(inductive reactance) = XL = 2π f L Fig. 21-36
(capacitive reactance) = XC = 1/(2π f C) Fig. 21-37
RLC series circuit
|Wednesday, Feb. 10|
Chapter 22. Electromagnetic Waves
In 1865 James Clerk Maxwell published a
four equations that basically unified electricity and magnetism.
There will be one or two questions on Test 3 about what you learn from this video.
|Friday, Feb. 12|
Video: "Tesla - Master of Lightning" -
watch the remainder.
Go to the Web page "Tesla - Inside the Lab" to obtain a description of Tesla's most important inventions:
1. AC Motor
2. Tesla Coil
4. Remote Control
5. Improved Lighting
Explanation of the Tesla coil - demo
Tesla unit (1960)
|Last update: Feb. 9, 2010|