Friday, June 6, 2008

Personal holiday

Juniors brainstormed on IB lab - what are the factors that affect the strength of an electromagnet.

They worked on this lab on Monday-Wednesday of next week.

Thursday, June 5, 2008

Seniors Last Day!!

Went over Magnetism test.

Handed back Physics Olympics Test Booklet.

Tuesday, June 3, 2008

Answered questions on magnetism in preparation for tomorrow's test.

Students took the Hewitt 60 question test.

Monday, June 2, 2008

Went over Electricity Test.

Magnetism test on Wednesday.
Went over worksheet on Magnetism.

For tomorrow, look at Hewitt problems on Magnetism Chp 23, 24. Also review quizzes and problems on Magnetism.

Hewitt test tomorrow on 60 questions.

Friday, May 30, 2008

Handed back graded Electrical Meters Lab and Circuit Exercise.

Electricity Test

Thursday, May 29, 2008

Students finished Circuit Exercise.

Students worked on Electricity Problem Set 2.

Described briefly what is on tomorrow's test on Electricity.

Wednesday, May 28, 2008

Students did Circuit Exercise lab and worksheet.

Also handed out Electricity Problem Set 2 for review for Electricity Test on Friday.

Tuesday, May 27, 2008

Handed back Electrical Measurements Lab.

Students finished Electrical Meters Lab.

Electricity Test on Friday
Magnetism Test Wednesday, next week.

Friday, May 23, 2008

Students finished Electrical Measurement lab if they had not done so.

Introduced Electrical Meters lab. Students worked on that lab. Most students constructed the voltmeter but did not get to the ammeter section. We will finish this lab on Tuesday.

Thursday, May 22, 2008

Physics Extravaganza wrap-up sheet.

Went around room asking about favorite demo.

Described how to use a multimeter. Explained resistor color codes. Students did the Electrical Measurements Lab.

Have students check with instructor before connecting power to circuits with ammeter.

Wednesday, May 21, 2008

Prepared for Physics Extravaganza.

Some students worked on their presentations. I packed equipment.
Other students painted signs.

Tuesday, May 20, 2008

Prepared for Physics Extravaganza.

Went over demos.
Hung flyers.

Monday, May 19, 2008

Last class day before IB exam.

Handed out summary.
Went over radioactive decay - types of decay (alpha, beta, gamma)
Described the rules for writing decay equations.

Briefly describes classes of particles (leptons (light), hadrons (heavy), gauge bosons (interactions)). In equations, lepton number is conserved as is baryon number.

Hadrons consist of mesons and baryons (particles like proton and neutron)
Leptons include the electron and neutrinos.
Gauge bosons include the photon.

To conserve lepton number, in the decay of a neutron into a proton and electron, you must also have an anti-neutrino.

Went over several decay equations showing that nucleon number, charge number, baryon number and lepton numbers must be the same on both sides of the equation.

Problems in radioactive decay:
Two ways of looking at decay: delta N/delta t = - lambda * N
lamba is the decay constant = decay rate/number of remaining particles

A = Ao * (1/2)^(t/T 1/2)
T 1/2 is the half life
A is the amount remaining
Ao = original amount

The relation between the two ways of looking at decay is: lambda = ln 2/halflife

Students did several problems on radioactive decay.

**************

Went over photon energies when an electron changes energy levels. Calculated energies of photons, wavelengths, and frequencies.

Showed table of quantum numbers:

n = principal quantum number n = 1,2,3,4...
l = orbital quantum number. For a given n, l = 0, 1, 2, n-1
ml = magnetic quantum number. For a given n and l, ml = l, l-1, ...0, -1, -2, -l
ms = spin quantum number. For the electron, ms = 1/2, -1/2

Also handed out summary packets for astrophysics option.

Friday, May 16, 2008

Went over photoelectric effect. Students worked some problems.

Thursday, May 15, 2008

Went over problems from supplemental problem sheet on magnetism.

Handed out Atomic Physics packets to IB students.

Wednesday, May 14, 2008

Went over RA 24.1

Discussed Faraday's and Lenz's Laws. Showed examples.

Demo of motor and generator.

Demo of magnet entering coil of wire.

Talked briefly about transformers.

We did problem 21 in class. Asked students to try the rest of the problems for homework.

Tuesday, May 13, 2008

Went over first four problems on magnetic problem worksheet.

Gave quizzes on magnetism.

Handed out RA 24.1 due tomorrow.

Monday, May 12, 2008

Went over RA 23.1.

Showed several examples of using the right hand rule:
a) JJ Thompson's discovery of the electron by measuring m/q
b) Hall effect showing that the charge carriers are electrons
c) mass spectrometer

Handed out RA 23.2, problems in magnetism, additional problems in magnetism

Asked students to do problems 1-4 in problems in magnetism sheet for tomorrow.

Friday, May 9, 2008

Answered one question on the electric circuit problem sheet 1.

Introduction to magnetism.

Showed that a magnet exerts a stronger force on the paper clips than the Earth.
Dick Tracy - He who controls magnetism controls the universe.

Sprinkled iron filings on paper over magnets (used simple bar magnet and horseshoe magnet under plastic crate). Showed patterns. Just as electric charges affect space, so do magnets. The filings align along magnetic field lines. Talked about North and South poles of magnetics. Opposite poles attract, like poles repel.

Showed maps of declination for US and world. Declination is the deviation between magnetic north and geographical north. Note, since the north pole of a compass points north and opposite poles attract, the magnetic north is actually a south magnetic pole. Also mentioned magnetic dip.

Showed with demo of wire and compasses that currents create a magnetic field. Showed Right Hand rule for current carrying wires. Point the thumb of the right hand in the direction of conventional current and the fingers curl in the direction of the magnetic field. Magnetic field lines are circles around the current carrying wire. The magnetic field = uo * I/(2 * pi * r).

k = 1/(4 * pi* eo)
Students calculated sqrt (1/(uo *eo) to get c.

Currents create magnetic fields. Changing magnetic fields in coils of wires create currents. Demonstrated with wires and galvanometer with horseshoe magnet and then more dramatically with the magnets in the coil of wire. Therefore changing magnetic fields create currents.

Showed using TV that magnets affect charges. Showed using oscilloscope that when you move the magnet left and right, the dot moves up and down. When you move the magnet up and down, the dot moves right and left. Must work in 3-D to do magnetism.

Showed second Right Hand Rule. Point the fingers of the right hand in the direction of velocity, curl the fingers to the direction of the magnetic field. The thumb points in the direction of force on a positive charge. If the charge is negative, flip the direction.

F = q V X B
Went over several examples finding direction of force. If v and B are co-linear, or the charge is at rest (v = 0), then F = 0.

Another way of writing the magnitude of the force is F = q v B sin (theta)

Showed examples of forces of one wire on another. First wire sets up a magnetic field at the location of the second wire. That magnetic field affects the moving charges. Wires with currents in the same direction attract, opposite direction and they repel.

Showed split ring commutator example for a motor.

Handed out RA 23.1 due Monday.

Thursday, May 8, 2008

Went over questions from Problem Sheet 1.

Gave out quizzes on electric circuits.

Handed out extra credit resistor problems - due on Monday for Extra Credit.

For tomorrow, finish doing problems on Problem Sheet 1.

Wednesday, May 7, 2008

Review of voltage, current, resistance, Ohm's Law, Power relationships.

Review of resistors in series and parallel - derived equations for finding equivalent resistance for series and parallel circuits.

Reviewed results of light bulbs from yesterday. 100 W bulb has lower resistance than 60 W light bulb but in series the 60 W light bulb will burn brighter.

Physiological Effects of Current lab/demo

Found dry and wet resistance of Tiffany and Travis.

Demonstrated and then discussed how to use voltmeters and ammeters and how to put them into circuits. Explained what would happen if you connected them incorrectly.

Assigned the remainder of problems from problem sheet 1 for homework.

Tuesday, May 6, 2008

Many students absent due to IB History test.

Went over RA 22.1

Introduced Ohm's Law: I = V/R
Showed how to find equivalent resistances for series (one after the other with a single path for current) and parallel (same potential difference across each element).

Showed demo of Christmas tree light hooked up in series and parallel. Investigated what happened to the brightness of the lights.

Derived P = I*V = I^2 *R = V^2/R

Talked about 60W and 100W light bulbs. Using them in parallel showed that the 100W light bulb has less resistance.

In series, the 60W light bulb would burn brighter since it has a higher resistance, would have a greater potential difference across it, and would dissipate more power.

Students worked problem 9 (combinations of resistors in series and parallel) in class. Assigned problems 1-8 (as well as 9 if they didn't finish) for homework.

Monday, May 5, 2008

Went over Electrostatics test

Collected RA 22.1

Handed out summary of electrostatics and electric current

Started Hewitt video on electric current

Friday, May 2, 2008

Test on electrostatics.

Handed out RA 22.1 due Monday.

Thursday, May 1, 2008

Quiz on finding electric field between charged parallel plates. Students redid it if they didn't get on the first try.

Used laptops to connect to WebAssign. Students worked either alone or in pairs to do the WebAssign problems from Giancoli chapter 16, 17.

Test tomorrow on Electrostatics: Force, Electric Field, Electric Potential

Wednesday, April 30, 2008

Ink jet quiz.
Went over quiz.

Went over problems from WebAssign.

Went over questions on problem worksheet.

Test on Friday on electrostatics.

Tuesday, April 29, 2008

Set up ink jet problem on board and allowed students time to work on it. (Also asked for number of excess electrons.)

Went over ink jet problem.

Summarized electric field and potential graphs for oppositely charged parallel plates, charged conducting shell, uniformly charged insulator.

Calculated work by integration of F . dr
E = F/q

V = work/q

Used same math techniques to calculate gravitational PE. Setting GPE at infinity to be zero, calculated the escape velocity from Earth.

Used same equation to calculate size of black hole with mass of Earth.

WebAssign due tonight 10:30PM
Test on Friday on Electrostatics.

Tomorrow we will start with a quiz on the ink jet problem and then go over any questions on the supplemental problem sheet and from WebAssign.

Monday, April 28, 2008

Went over RA 21.3 - electric potential

6 quiz problems on Coulomb's law, electric force, electric field, electric potential.

Assigned WebAssign due Tues 10:30 PM

Tomorrow we will finish up electrostatics and do an ink jet problem.

Friday, April 25, 2008

Went over RA 21.1, 21.2

Discussed charge distribution and electric field for conductors. Drew plots of force vs distance for spherical mass, charged conducting spherical shell, charged solid conducting sphere.

Went over "rules" for drawing electric field lines.

Showed computer program for electric field lines.

Collected RA 21.3

Handed out Coulomb's law problems.

Thursday, April 24, 2008

Went over Relativity test results.

Started electrostatics with introductory lecture. Showed demos using electroscopes.

Charge an ebonite rod by rubbing it with fur (charge by friction). This rubs electrons off the fur and onto the rod.
Bringing the charged rod near the electroscope causes the leaves to spread (like charges repel).

Charge the electroscope by contact.

Now bringing the charged rod close to the electroscope causes the leafs to spread further apart.

Bring the fur (positive charge) near the electroscope causes the leafs to fall back.

Drew pictures showing charges.

Demonstrated and showed with pictures charging by induction.

Demoed the pith balls.
Demoed polarization of charge by attracting a stream of water using both negatively and positively charged strips.

Handed out electrostatics mini-labs. Students tried various activities including the Van De Graff.

Collected RA 21.1, RA 21.2.
Handed out RA 21.3 for homework.

Tuesday, April 22, 2008

Relativity test.

Homework: Reading Assignment 21.1, 21.2 due on Thursday.

Monday April 21, 2008

Reviewed ideas of General Relativity from Friday - in particular the kindergarten approach to time ticking slower near source of gravity.

Calvin and Hobbes intro to Principle of Equivalence.

Principle of Equivalence worksheet.

Pound Rebka worksheet.

Test tomorrow.

Friday, April 18, 2008

Went over problems 14 in problem sheet.

Went over Giancoli problems in relativity. Students did well on them.

Showed graphs of mass vs speed and speed vs time for a constant force (both Newtonian and Relativistic).

Introduced General Relativity.
Sprang from the mind of Einstein in 1916 paper.
General, because it handles acceleration, whereas the special theory of relativity only dealt with the special case of reference frames moving with respect to each other at constant velocity.

Life on Flat World skit.
We live on a sphere so it is possible to head off in opposite directions and meet.
Happens also in space. Satellite above Earth sends off two probes in opposite directions. They meet because they both orbit the Earth. Newton attributes this to gravity. Einstein said space itself is curved.

Mass tells space how to curve, space tells objects how to move. If you have a rubber sheet with nothing on it, it is flat. If you place objects on the sheet, it will sag. Objects moving on the sheet are affected by the sags and tend to be deflected towards the depressions.

Kindergarten view of General Relativity:
1. Light has energy
2. Energy and mass are connected (E = mc^2)
3. Mass is affected by gravity.
4. Light is affected by gravity.
5. Show thick light beam. If no mass, the beam is straight. If there is mass, the beam is bent. A runner around the track on an inside lane has an advantage because the path is shorter. The inner part of the light beam travels a shorter distance. But...since the speed of light is the same for all observers, the clock for the inner beam ticks more slowly (less ticks). Clocks run slow near sources of gravity!!

Note the difference between clocks in special relativity and those in general relativity. In special relativity, as you go by, I see your clock ticking slow. You are at rest in your rest frame and see me going by. You see my clock as ticking slow. We each see each others clock as ticking slow.

In general relativity, I am in the attic and you in the cellar. I see your clock ticking slow, you see my clock ticking fast. We each see our own clocks ticking correctly but see the differences in the other person's clock.

A black hole is a strong source of gravity. As you approach the black hole, I see your clock running slow, you see my clock running fast. You look back and see the entire future of the universe.

For homework, please look at Hewitt Relativity.

Thursday, April 17, 2008

Went over homework problems 8-13.

Reassigned problem 14 for homework. Handed out Giancoli problem packet.

Hope to wrap up Special Theory of Relativity and start General Theory tomorrow.

Test on Tuesday.

Wednesday, April 16, 2008

Handed back time dilation quiz. Asked students who did not get it correct to redo it on back and hand in.

Introduced Length Contraction with Thought Experiments. Came up with equation for length contraction. Showed by proof by contradiction that the length is contracted only in the direction parallel to the direction of motion, NOT in a direction perpendicular to the motion.

Redid the quiz first using time dilation and then using length contraction to calculate what the astronaut's "odometer" would read. The results were consistent as they must be.

Introduced idea of increase in mass with speed along with the mass equation.
Used examples of bouncer with roll of quarters, Andy and Bill trying to punch each other, and Bonnie and her sister.

Like other waves, light has energy, but unlike other waves, light also has momentum (comet tails always point away from the Sun). If light has energy, it also has mass. It has mass because it has energy.

The total energy of an object is, from Einstein's equation, E = mc^2 = mo c^2 + KE
where mo is the rest mass. You cannot use KE = 1/2 m v^2 when dealing with relativistic speeds.

Assigned problems 8-13 for homework.

Test next Tues/Wed

Tuesday, April 15, 2008

Reviewed simultaneity. If Bonnie sends signals to light lamps at either end of her spacecraft, she will be illuminated by each at the same time. You too will see her illuminated by both at the same time but you will see the rear light light first and then the front light.

Went over homework problems.

Quiz on time dilation.

Hewitt video on Time Dilation.

No homework for this evening.

Monday, April 14, 2008

Went over Waves Test.

Talked about Hugh Hunter Scholarship.

Around the room review of topics covered last time in relativity.

Went over homework problems.

Continued relativity - finished simultaneity.

Derived time dilation equation from light clocks. Showed graphical example.
Handed out Han Solo problem.

Assigned problems 4,5,6,7 (7 is hard).

Thursday, April 10, 2008

Didn't have time to grade tests so didn't hand them back today.

Intro to Relativity.
Gave intro
Went through first 6 thought experiments.
Discussed relativistic correction to the relative velocity equation.
Students did worksheet on simultaneity. Went over worksheet.

Handed out problem sheet. Assigned problems 1-3 for homework - due Monday.

Wednesday, April 9, 2008

Students took wave test.

Tuesday, April 8, 2008

Constanza redid the wavelength lab after school in which we measure the wavelength of laser light using a ruler. Students who previously did it got values that did not make sense, much too small a wavelength. When Constanza did it, she used a very small angle for the light hitting the ruler (> 4 degrees). The pattern showed clear maxima on the whiteboard but a lot of garbage in between. I think that with using a greater angle and having the maxima closer, it might be harder to distinguish the garbage from real maxima. Thinking that the garbage patterns were really maxima would give too many maxima for the same distance giving a wavelength that was too small. Constanza got a value of 700 nm which is pretty good.

Reviewed for the Waves test with a student led competition.

Students divided themselves into three teams and tried to answer questions posed by Jason, Brandon, and Travis.

Questions included refraction and critical angle, wave properties, a Doppler Effect problem with echoes (how many reflections to get above a certain frequency from a car moving towards a wall), which diffracts more: an audible sound wave or a radio wave.

Everyone did a great job!!

Monday, April 7, 2008

Showed Women in Art video clip - pretty cool.

Answered questions from WebAssign.

Travis led class in going over the refraction worksheet.

Went around room listing things that might be on Wednesday's test.

Jason and Travis will lead the review tomorrow.

Friday, April 4, 2008

Went over homework on superposition, critical angle (refraction), and Doppler Effect.

Started review using outline.

Assigned WebAssign: Chapter 18, Chapter 19, Problems in Waves.

Thursday, April 3, 2008

Collected diffraction labs. Checked measuring wavelength with a ruler data.

Went over homework problems on waves.

Students worked problems on standing waves and resonance and refraction.

For homework, assigned problems page 3: 1,2, page 5: 10, Page 8: 2,5, Page 9: 8

Waves test on Tuesday.

Wednesday, April 2, 2008

Reviewed diffraction lab.

Students derived 2-slit diffraction formula.

Beats: demo with QBASIC, demo with combs

Doppler Effect for Sound: Handed out and went over notes. Derived equations for moving receiver and moving source.

Handed out wave problem packet. Assigned problems from packet - due tomorrow.

Tuesday, April 1, 2008

Quick review of Reflection and Refraction.

Refraction demo of people walking.

Diffraction: Longer wavelengths diffract more. You can hear around a corner but not see around a corner.

Young's two slit diffraction.

Students did lab measuring wavelength using double slit and also using ruler.

Monday, March 31, 2008

Collected Saving Jack Labs.

Only 10 of 18 students present.

Students solved wave and standing wave problems.

Summarized properties of waves: reflection, refraction (Snell's Law, index of refraction, critical angle)

Started diffraction - Young's Two Slit example. The closer the slits, the farther apart the maxima.

Friday, March 21, 2008

Lab Day for Waves

Demonstrated Belly-Dancing Tuning Forks.

Set up Dave Cross Wave Machine. Students were asked to determine how the wave speed depends on the number of nodes and the tension in the string.

Set up resonance tube with water. Students were asked to calculate the resonant depths and then verify by experiment.

Snell's Law Lab. Students were asked to measure the index of refraction of water and calculate the speed of light in water.

Reviewed results for the last 20 minutes of class.

Thursday, March 20, 2008

Gave students 30 minutes to finish up their "Save Jack" Labs.

Handed back RA 18.1, RA 18.2
Went over work sheets

Showed examples of superposition. Propagate waves than just algebraically add up the waveforms.

Electromagnetic spectrum: Radio waves, microwaves, infrared, Visible (R-O-Y-G-B-I-V), Ultraviolet, X-rays, gamma rays. Used v = wavelength * freq to calculate the wavelengths of AM and FM radio waves. Wavelength of microwave from microwave oven.
Used Wien's Law to calculate wavelength emitted by our bodies (infrared). Red wavelengths ~700 nm. Violet ~ 400 nm.

Demo that TV emits radio waves that we can pick up on radio set to static AM.
Discussed how microwaves cook food - resonant frequency with water molecules.
Showed how remotes, which emit IR, can be detected using a photocell and speaker, or by cell phone camera.

Standing waves: String fixed at both ends. v = sqrt(tension/(mass/length)).
Drew patterns of fundamental (first harmonic), and second and third harmonics for string, open pipe, and pipe open at one end and closed at the other. Derived general formulas for frequency for the various harmonics.

Used water filled pipe to find resonances.

Handed out worksheets on superposition and standing waves.

Wednesday, March 19, 2008

Students worked on the "Saving Jack" Lab all period.

Tuesday, March 18, 2008

Lab Day
Students did the:
Speed of Sound in Air Lab
Tones, Vowels, and Telephones Lab (didn't finish)
Speed of Sound in Aluminum Lab

Asked for write-ups that were terse and pithy covering the main idea and results.

Tomorrow we do the "Save Jack" lab

Monday, March 17, 2008

Went over Thermodynamics test.

Intro lecture on waves. A wave is a wiggle in space and time.

A wave is a way of transferring energy without the movement of matter from one place to another.

Waves can be classified as transverse or longitudinal, or mechanical or electromagnetic. Went over properties of each.

Derived wave speed formula.

Students did the Slinky Lab

Homework: Plan for Save Jack Lab on Wed.

Wednesday, March 12, 2008

Went over RA 17.2.

Lectured on the Second Law of Thermodynamics.

Explained the various statements of the Second Law.

Defined entropy. Showed how to calculate the change in entropy.

Gave students a practice test on Thermodynamics which they worked on in groups.

Handed out RA 18.1 and RA 18.2 for homework over the long weekend.

Tuesday, March 11, 2008

Went over RA 17.2
Showed how to draw schematics of thermodynamic systems.

Went over First Law of Thermo sign convention worksheet.

Did problem of heat engine with ideal gas as a class.

Handed out "Save Jack" problem for IB Lab (Planning (A), Planning (B), Data Collection, Data Analysis, Conclusions. Watched part of Titanic to get "feel" and background for the problem. Plan on doing lab next week.

Monday, March 10, 2008

Went over Heat test.

Went over RA 17.1 with emphasis on the sign convention for the first law of thermodynamics.

HW: RA 17.2, First Law sign convention worksheet.

Friday, March 7, 2008

Test on Heat and Temperature

Handed out RA 17.1 due Monday
There is a WebAssign assignment but I think I forgot to mention it.

Thursday, Mar 6, 2008

Review for Test.

Asked questions around the room.

Went over Thermal Concepts problems.

Test tomorrow.

Wednesday, March 5, 2008

Handed out Kinetic Theory Worksheets.

Travis ran the class going over the worksheet. Great Job Travis!

Tomorrow we will go over any questions from Thermal Problems worksheet and the summary review sheet.

Friday: Test on Heat

Tuesday, March 4, 2008

Answered questions and talked briefly about the Newton's Cooling Lab. Students will answer the analysis questions, being sure to say in their answers what they are answering, by Friday.

Handed back Heat Capacity Labs

Students spent the period working on the Thermal Problems Worksheet.

Test on Friday

Monday, March 3, 2008

Students set up for Newton's Cooling Lab.

While running, I reviewed the Heat Capacity Lab with emphasis on controlling variables, especially heat loss.

When students write up the Power from the Sun Lab, I want to see at least 5 main points in reviewing the procedure and 5 main points in modifying or improving the procedure. This lab will be written up to satisfy the data collection, data processing, and conclusions sections of an IB lab.

Students analyzed Newton's Cooling curves using the automatic curve fit function. Students looked at the coefficients for the fit curve. If they were not reasonable, students entered in the Room Temperature and rechecked the coefficients. Students got reasonable results with this correction.

Students wrote up questions 1-9 in the lab analysis section. If they did not finish, finish for homework.

Friday, Feb 29, 2008

Quest for the Nobel Prize competition

HW: work on problem set, do WebAssign problems

Next week: Newton's Law of Cooling Lab, Titanic Lab
Test on Friday

Thursday, Feb 28, 2008

Went over RA 15.1, RA 16.1

IB students went off in pairs to do the Power of the Sun lab in the courtyard using the 200 W light bulb. The focus of this lab is on handling the uncertainty calculations.

The rest of the students worked on the Thermal Concepts problem sheet.

By popular watched the first 15 minutes of the Bill Nye video on Heat.

Assigned WebAssign Chapter 15 due Sunday evening.

Wednesday, Feb 27, 2008

Collected Heat Capacity Labs

Reviewed topics from yesterday - conduction, convection, radiation

Showed how to estimate the average temperature of the Earth assuming 30% reflection. Calculated 257 K.

Showed Hewitt video on Change of State

Discussed heating curve of water with phase changes.

Handed out RA 16.1 - due tomorrow

Assigned WebAssign Chapter 15 - Heat Transfer - due Sunday night

Tuesday, Feb 26, 2008

Collected RA 15.1. Graded it while students finished watching the Hewitt video on Heat Transfer.

Demonstrated the wax brightness lab and showed how to do calculations. Described the lab to calculate the power output of the Sun which we will do the next bright sunny day.

Reviewed with class conduction, convection, and radiation. Gave examples of convection and how it affects onshore and offshore winds.

Introduced Wien's Law and the Stefan-Boltzmann Law. Showed how to use Wien's Law to get the wavelength of maximum emission. Used the Stefan-Boltzmann Law to show how the Intensity vs Wavelength curve various with temperature. At higher temperatures the wavelength of maximum emission shifts towards shorter wavelengths but an object at higher temperature emits more radiation at all wavelengths.

Discussed colors of stars and showed the Intensity (W/m^3) vs wavelength curves for various temperature stars.

Calculated the wavelength of maximum emission for a human. Showed how to calculate the power radiated by a human assuming emissivity = 1.

Talked briefly about the concept of a black body which is an object that absorbs at all wavelengths and emits at all wavelengths. Stars can be approximated as black bodies.

Heat Capacity Lab due tomorrow.

Monday, Feb 25, 2008

Handed back Oleic Acid Labs - discussed uncertainty calculations

Lectured on Heat Transfer
Conduction: molecular collisions and collisions between loose electrons in objects that are in direct contact.

Introduced idea of temperature reservoir
Deduced equation for heat flow
Showed that temperature profile in a uniform conductor is a straight line
Solved a problem to find junction temperature at the junction of two materials
Generalized to say that if the temperature difference is great (for the same thickness), the thermal conductivity is small.

Demo with star of different metals. On which does the wax melt first.

Convection
Demo with hot and cold water volcanoes.

Started Hewitt video on Heat Transfer.

Handed out RA 15.1 - due Tuesday

Friday, Feb 22, 2008

Students did Heat Capacity Lab.

Lab write-up is due Wednesday of next week.

Thursday, Feb 21, 2008

Showed Jearl Walker video on Leidenfrost effect.

Went over RA 14.2, RA 14.3.

Handed out lab sheet and assessment sheet for Heat Capacity Lab which students will do tomorrow (Friday).

Showed Hewitt video on Temperature, Heat and Expansion up to freezing pond.

Students have WebAssign problems chapter 14 to work on - due tomorrow.

Wednesday, Feb 20, 2008

Collected Oleic Acid Lab Reports, RA 14.3

Introductory lecture on Heat and Temperature

Temperature: Measure of how "hot" or "cold" an object is. On a microscopic scale, it is proportional to the random kinetic energy of the particles.
This idea is powerful. In a room full of air, all the molecules, on average, have the same KE. Since an oxygen molecule has more mass than a nitrogen molecule but they have, on average, the same KE, you can compare the average speeds of the molecules. The nitrogen molecule is moving faster by a factor of the square root of the ratio of their atomic masses.

Internal Energy: This is the total random energy of all the particles in a substance. It includes the random KE (jiggling, rotation, vibration) as well as associated PE due to vibration and intermolecular forces.

Heat: Energy that is transferred from one object to another due to a difference in temperature. Note that the Atlantic Ocean has way more internal energy than a cup of hot coffee but if you mix the two, energy will be transferred from the coffee to the ocean.

Temperature scales: Discussed Fahrenheit, Rankin, Celsius, Kelvin - what the temperatures are for each at absolute zero, freezing point of water, boiling point of water, and how you can sus out how to convert from one scale to another.
Showed a picture of the range of temperatures.
Discussed how absolute zero can be determined using a constant volume thermometer and extrapolating to zero pressure.

Heat Capacity, Specific Heat Capacity: This is a type of thermal inertia - a measure of how much the substance resists a change in temperature for a given amount of heat energy. The greater the heat capacity, the greater the thermal inertia and the smaller the change in temperature for a given amount of heat energy. Water has a large specific heat capacity = 4180 J/kg-K. Demo of heat capacity.

Lead had a much smaller specific heat capacity than aluminum since, for the same mass, there are many more atoms of aluminum. If you supply a quantity of heat energy, it has to be spread among the many atoms of aluminum, so each atom gets less energy and thus a smaller increase in temperature.

Showed how degrees of freedom affect specific heat capacity and showed a graph of when (at what temperatures) the rotational and vibration modes kick in for hydrogen gas. Because a diatomic gas has more degrees of freedom than a monoatomic gas, it has a greater heat capacity.

Discussed Heat Capacity Lab that students will do on Friday.

Linear expansion: Most substances increase in size when heated since the particles are jiggling more and take up more space. If you have a rod of length L, for a change in temperature delta T it will increase in length by delta L. If you have two identical rods, each will increase in length the same amount. If you put them together to make a rod twice a big, the expansion is twice as much. Showed how to derive the equation for linear expansion: delta L = alpha * L * delta T where alpha is the coefficient of linear expansion that depends on the material.

Demonstrated expansion using bimetallic strip (brass and steel) and ball and ring.

Derived area and volume expansion equations.

If you heat a hole, it also expands.

Demoed ivory soap and CD in microwave.

Homework: work on WebAssign problems.

Tuesday, Feb 19, 2008

Went over SHM test.

Went over RA 14.1.
Temperature scales: Fahrenheit, Celsius, Kelvin
Kelvin: don't say "degrees" Kelvin. Kelvin scale MUST be used if the temperature is and absolute temperature and not a temperature difference, as in the ideal gas law, PV = nRT
Internal Energy: Total energy of all the particles
Heat: Energy that flows from one object to another based on temperature difference
Temperature: Measure of how "hot" or "cold". Measure of the average random kinetic energy.
Difference between internal energy and temperature

Degrees of freedom: monoatomic, diatomic with rotational modes, metallic crystal with KE and PE
Heat Capacity: On average, energy is shared equally between all degrees of freedom and between all particles.

Collected RA 14.2
Handed out RA 14.3 - due Wednesday
Assigned WebAssign Chapter 14 due Fri
Oleic Acid due Wednesday

Friday, Feb 15, 2008

Collect RA 14.1
Redo on some problems on SHM test

Oleic Acid Lab, due Wed next week

Homework: RA 14.2

Thursday, Feb 14, 2008 - Valentine's Day

Test on Chapters 10, 11 and SHM

Handed out RA 14.1 due tomorrow

Wednesday, Feb 13, 2008

Handed back AAPT test booklets.

Reviewed reading assignment sheet on scaling.

Answered questions and solved problems on SHM.

Worked out SHM problem for tunnel through Earth.

Derived equation for gravitational potential energy. Showed how it can be used to determine escape velocity.

Test tomorrow on Ch 10, 11, SHM

Tuesday, Feb 12, 2008

Day to work on problems and problem solving techniques.

Monday, Feb 11, 2008

Collected RA on density and Hooke's Law

Went over some of the WebAssign problems on SHM. Will give an extension for the assignment.

Showed how to measure small distances using a micrometer.

Students did BB Pancake Lab. Due Tuesday for extra credit, due Wed as last day.

Handed back Reading Assignment on density and Hooke's Law.
Handed back Excel spreadsheet lab sheets.

Friday, Feb 8, 2008

Went to library computer lab. Students downloaded Excel spreadsheet from WebAssign (go to Communications). Note that there is an error in the spreadsheet - it is two pages long and I left my name on the second sheet. Students should enter their own names.

Students completed the spreadsheet lab on uncertainties that corresponded to the worksheet on uncertainties. Students printed out their results.

When done, students worked on a second spreadsheet for uncertainties for the Rocket Lab.

Students who had not taken IB Physics 1 started with the Introduction to Excel spreadsheet lab corresponding to the graphing of round objects lab.

Homework for Monday is to complete and hand in RA 11.2 (density and Hooke's Law) and to do the WebAssign problems on SHM.

Thursday, Feb 7, 2008

Collected Spring Constant Labs

Went over RA Chapter 10
Example of atom to football field.
Example of Milky Way galaxy to football field - calculated number of stars in galaxy.

Reviewed electromagnetic spectrum
Radio, Microwaves, Infrared, Visible (ROY G BIV), Ultraviolet, X-Rays, Gamma Rays
Used speed = wavelength * frequency to calculate wavelengths of AM and FM radio waves

Used E = mc^2 to calculate mass to energy

Collected RA Chap 11 Scaling, graded, and handed it back
Showed Hewitt video on scaling

Wednesday, Feb 6, 2008

Work Day
Allowed students time to finish Spring Constant Lab due Thursday
Students could also work on Pumpkin Lab part 1
Assigned WebAssign Chapter 11 SHM due Sunday 10 pm
Handed out RA11.2 due Thurs

Tuesday, Feb 5, 2008

Lecture on Dealing with Uncertainty in Physics
Lectured on uncertainties:
1. If you have multiple measurements:
Find the average by: (M1 + M2 + ... + Mn)/n
Find the uncertainty by: (abs(M1-avg) + abs(M2-avg) + ... + abs(Mn-avg))/n

2. If you have one measurement of each quantity:
2a. Max Min method
Example of area of a rectangle
Max area = (L + uncL)*(W + uncW)
Min area = (L - uncL)*(W - uncW)
Avg area = (Max area + Min area)/ 2
Unc Area = (Max area - Min area)/ 2

2b. Method of Relative Uncertainty
This method cannot be used if the terms are added or subtracted but otherwise is powerful and easy to use
Used example of area of a rectangle
Area = L * W
Unc Area = A * (uncL/L + uncW/W)

If you have a complicated expression like: Z = (A^1/2) * (B^3)/(C^5)
you can use this method taking the absolute values of the exponents as coefficients in the relative uncertainty equation: uncZ = Z*((1/2)*uncA/A + 3*uncB/B + 5*uncC/C)

Handed out practice sheet on uncertainties with summary of class notes - will post answers in answer folder.

Students did Spring Constant Lab - uncertainties not needed
Write-up: Name, Partners, Date, Lab Title
Data Table
Picture with calculations
Results: Discuss summary questions
Answer questions making sure to explain in answer what it is you are answering

Spring Constant Lab due on Thursday

Talked about Pumpkin Labs
Part 1: Emphasize Data Collection and Data Manipulation
Part 2: Emphasis on IB Planning (b) (Method), and Conclusions

Monday, Feb 4, 2008

Students took AAPT Physics Olympics test.
(75 minutes, from 11:20 - 12:35)

Friday, Feb 1, 2008

Went over problems from SHM worksheet.

Did some of the problems from AAPT practice test including problems in SHM, friction and coefficient of friction, conservation of energy, work.

Showed Parallel Axis Theorem for calculating Moment of Inertia (Rotational Inertia).

AAPT Physics Olympics Test will be given 3rd period on Monday, Feb 4.

I am giving points for completion (or good effort in completing) WebAssign assignments WA Hewitt Review ch. 2-4, and WA Hewitt Review ch 5-8. Current due date is Sunday, Feb 3, 2008.

Thursday, Jan 31, 2008

Intro Lecture on SHM.
My lecture notes are available as a word file in WebAssign under Announcements.

Handed out problems sheet on SHM - try problems for Friday.

On Friday I will go over and answer questions of any of the problem sets:
Review of IB Physics 1, AAPT Practice Test, SHM Problem Sheet

AAPT test is on Monday.

Wed Jan 30, 2008

Collect Parent Contact form, Course Syllabus form
Check textbooks for covers

At Library Computer lab:
Students logged into WebAssign and did Intro to WebAssign 2007
Logged into course blogsite
Started WebAssign assignments Hewitt chap 2-4, Hewitt chap 5-8 as review

Go over questions from "Review Problems from IB Physics 1" worksheet
Went over questions 1-7 on AAPT Physics Olympics Practice Test
Mentioned i, j, k notation for vectors
Reviewed difference between distance and displacment
Did problem in average velocity = change in displacement/time interval

HW: Continue working on review problems, attempt AAPT Physics Olympics Practice Test

Tuesday, Jan 29, 2008

Introduction
Student Profile
Hand out Course Syllabus
Course Syllabus completion sheet due Wed
Parent Contact sheet - due Wed
Get textbooks - cover by Wed
Review IB Physics by going over Final Exam using ABCDE cards
Hand out Problem sheet for review of IB Physics 1 - students should try problems
Hand out AAPT Physics Olympics practice exam

Tomorrow I plan to have students go to the Library Computer Lab to Log onto WebAssign, complete the introductory exercise, and try logging onto this blog site.

Welcome

This will hopefully be a daily recap of what we do in class.