Ink jet quiz.
Went over quiz.
Went over problems from WebAssign.
Went over questions on problem worksheet.
Test on Friday on electrostatics.
Wednesday, April 30, 2008
Tuesday, April 29, 2008
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.
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
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.
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
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.
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
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.
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
Monday, April 21, 2008
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.
Calvin and Hobbes intro to Principle of Equivalence.
Principle of Equivalence worksheet.
Pound Rebka worksheet.
Test tomorrow.
Friday, April 18, 2008
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.
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
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.
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
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
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
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.
Went over homework problems.
Quiz on time dilation.
Hewitt video on Time Dilation.
No homework for this evening.
Monday, April 14, 2008
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).
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
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.
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
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!!
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
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.
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
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.
Started review using outline.
Assigned WebAssign: Chapter 18, Chapter 19, Problems in Waves.
Thursday, April 3, 2008
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.
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
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.
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
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.
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.
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