IB Physics Help Video Podcast

A video podcast for high-school students studying physics

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Video Episodes:

Quick Demo: Eddy cu...
5 Views
16:33:00 10/22/11

A spinning copper disc is slowed down when a magnet is brought near it. Note that copper is not a magnetic material. Eddy currents are induced in the disc due to ...

Quick Demo: Eddy current brake

Added 10/22/11
5 Views

Quick Demo: Eddy current brake

[LESS INFO] 5 VIEWS | ADDED 16:33:00 10/22/11
A spinning copper disc is slowed down when a magnet is brought near it. Note that copper is not a magnetic material. Eddy currents are induced in the disc due to the relative motion of the disc and the magnet. The magnetic fields associated with these currents have such a direction that they oppose the cause that created them in the first place (Lenz rule). As a result they oppose the relative motion between the disc and the magnet and hence the disc is slowed down.

Episode #9: Electro...
7 Views
22:30:58 05/14/11

This episode is an introduction to electromagnetic induction. The presentation is supported by many experimental demonstrations. The video covers the following t...

Episode #9: Electromagnetic Induction

Added 05/14/11
7 Views

Episode #9: Electromagnetic Induction

[LESS INFO] 7 VIEWS | ADDED 22:30:58 05/14/11
This episode is an introduction to electromagnetic induction. The presentation is supported by many experimental demonstrations. The video covers the following topics: 1. Oersted%rsquos discovery of the magnetic effect of an electric current (sometimes called the %ldquomotor effect%rdquo as it is the principle behind simple DC motors); 2. Faraday%rsquos discovery of electromagnetic induction; 3. Magnetic flux; 4. Flux linkage; 5. Faraday%rsquos law of electromagnetic induction; 6. Lenz%rsquos law (or Lenz%rsquos rule); 7. Eddy currents and their braking effect.

Quick Demo: Variati...
6 Views
12:56:00 04/11/11

The current drawn by a simple motor may vary in time depending on what the motor does at any given instant. 1. When a motor is connected to a battery, the curre...

Quick Demo: Variation of the electric current in a DC motor

Added 04/11/11
6 Views

Quick Demo: Variation of the electric current in a DC motor

[LESS INFO] 6 VIEWS | ADDED 12:56:00 04/11/11
The current drawn by a simple motor may vary in time depending on what the motor does at any given instant. 1. When a motor is connected to a battery, the current in the coil (or armature) increases dramatically but as soon as the coil starts rotating increasingly faster, the current drops and settles at a certain value. This is because of the so-called "back emf" induced in the coil as it rotates in a magnetic field (Faraday's law). The back emf has such polarity that it opposes the emf of the cell (Lenz's law). 2. When the motor spins and there is no load attached, the current stays constant. (The value of the current is I = (emf_cell - back_emf)/R where R is the total resistance of the circuit, including any internal resistance of the battery) 3. When the motor does work on an external load and it slows down, the back emf drops as its value depends on how fast the armature spins. As a result, the current through the motor increases up to a value that depends on how "hard" the motor works.

Episode #8: Simple ...
1 Views
18:35:56 03/10/11

Topics covered in this episode: (a) The period of a gravitational pendulum (b) Using a gravitational pendulum to determine the acceleration due to gravity, g, (c) ...

Episode #8: Simple Harmonic Motion (Part 2)

Added 03/10/11
1 Views

Episode #8: Simple Harmonic Motion (Part 2)

[LESS INFO] 1 VIEWS | ADDED 18:35:56 03/10/11
Topics covered in this episode: (a) The period of a gravitational pendulum (b) Using a gravitational pendulum to determine the acceleration due to gravity, g, (c) Measuring mass using harmonic oscillators, (d) Energy in SHM, (e) Connection between SHM and uniform circular motion.

Quick Demo: Voltage...
19 Views
17:39:25 01/02/11

This video shows a simple circuit consisting of a light bulb and a variable resistor (rheostat). The voltmeter measures the voltage across the terminals of the bat...

Quick Demo: Voltage across terminals of a battery

Added 01/02/11
19 Views

Quick Demo: Voltage across terminals of a battery

[LESS INFO] 19 VIEWS | ADDED 17:39:25 01/02/11
This video shows a simple circuit consisting of a light bulb and a variable resistor (rheostat). The voltmeter measures the voltage across the terminals of the battery: V = emf - Ir , where emf is the electromotive force of the battery, I is the electric current in the circuit and r is the internal resistance of the battery. When the switch is open, I = 0 and V = emf. When the switch is closed, a current flows through the circuit and V = emf - Ir . V can also be calculated as IR where R is the total resistance of the circuit. If R is increased, I decreases and V increases (as the product Ir gets smaller and V = emf - Ir ).

Quick Demo: Applica...
20 Views
17:19:00 01/02/11

This video shows a couple of torches/flashlights that use electromagnetic induction to function. They do not need batteries. The second part of this video shows a ...

Quick Demo: Applications of electromagnetic induction

Added 01/02/11
20 Views

Quick Demo: Applications of electromagnetic induction

[LESS INFO] 20 VIEWS | ADDED 17:19:00 01/02/11
This video shows a couple of torches/flashlights that use electromagnetic induction to function. They do not need batteries. The second part of this video shows a simple handheld electric generator which is one of the most common applications of electromagnetic induction. The video also shows that the electric generator is nothing else than an electric motor used in reverse (i.e. instead of putting a current through a coil placed in a magnetic field in order to obtain motion, we turn the coil in a magnetic field in order to generate an induced current).

Quick Demo: Electro...
26 Views
19:03:00 12/30/10

When a magnet is moved in or out of a coil, a current is induced in the coil. The size of the induced current depends on how fast the magnet is moved. The directio...

Quick Demo: Electromagnetic induction

Added 12/30/10
26 Views

Quick Demo: Electromagnetic induction

[LESS INFO] 26 VIEWS | ADDED 19:03:00 12/30/10
When a magnet is moved in or out of a coil, a current is induced in the coil. The size of the induced current depends on how fast the magnet is moved. The direction of the induced current depends on the polarity of the magnet and on the direction in which the magnet moves (i.e. towards the coil or away from the coil). The size of the induced emf (voltage) across the two ends of the coil can be determined from Faraday%rsquos law. The %ldquopolarity%rdquo of the induced emf can be determined from Lenz%rsquos law.

Quick Demo: Motor e...
34 Views
18:46:00 12/30/10

A current-carrying conductor placed in a magnetic field experiences a force. The direction of this force depends on the direction of the magnetic field and the dir...

Quick Demo: Motor effect

Added 12/30/10
34 Views

Quick Demo: Motor effect

[LESS INFO] 34 VIEWS | ADDED 18:46:00 12/30/10
A current-carrying conductor placed in a magnetic field experiences a force. The direction of this force depends on the direction of the magnetic field and the direction of the electric current. If the conductor is perpendicular to the magnetic field lines, the size of the force can be calculated using the formula F = B x I x L where B is the magnetic field strength, I is the electric current and L is the length of the conductor in the magnetic field. This effect is sometimes called the %ldquomotor effect%rdquo as it is the basic principle behind an electric motor.

Quick Demo: Magneti...
26 Views
17:24:00 12/30/10

When a current passes through a conductor or a coil, a magnetic field is created in the surrounding space. Its presence can be revealed by using a compass needle. ...

Quick Demo: Magnetic effect of an electric current

Added 12/30/10
26 Views

Quick Demo: Magnetic effect of an electric current

[LESS INFO] 26 VIEWS | ADDED 17:24:00 12/30/10
When a current passes through a conductor or a coil, a magnetic field is created in the surrounding space. Its presence can be revealed by using a compass needle. Changing the direction of the current changes the polarity of magnetic field produced.

Episode #7: Simple ...
10 Views
16:30:00 11/07/10

This video is an introduction to simple harmonic motion (SHM). SHM is a type of periodic motion for which the force that drives it is proportional to the displa...

Episode #7: Simple Harmonic Motion (Part 1)

Added 11/07/10
10 Views

Episode #7: Simple Harmonic Motion (Part 1)

[LESS INFO] 10 VIEWS | ADDED 16:30:00 11/07/10
This video is an introduction to simple harmonic motion (SHM). SHM is a type of periodic motion for which the force that drives it is proportional to the displacement from the equilibrium position. What is the equation that describes this type of motion? The answer and more in this episode. This first part covers the basics of SHM. The second part (a separate video, Episode #8) covers, amongst other things, some practical applications of SHM. The video is also available on my Vimeo , Blip.tv and Youtube channels.

Episode #6: Graphs ...
104 Views
21:11:00 09/17/10

What is the purpose of plotting various graphs for moving bodies? How are quantities like displacement, velocity and acceleration calculated from graphs of motion?...

Episode #6: Graphs of Motion

Added 09/17/10
104 Views

Episode #6: Graphs of Motion

[LESS INFO] 104 VIEWS | ADDED 21:11:00 09/17/10
What is the purpose of plotting various graphs for moving bodies? How are quantities like displacement, velocity and acceleration calculated from graphs of motion? This podcast covers the three main types of graphs: displacement-time, velocity-time and acceleration-time graphs. This video is also available on Youtube , Vimeo and Blip.tv

A 10-minute overvie...
4 Views
12:49:00 08/12/09

What is IB Physics? Are you a student who is just about to start the course? This presentation is a 10-minute overview of the IB Physics course.

A 10-minute overview of the IB Physics course

Added 08/12/09
4 Views

A 10-minute overview of the IB Physics course

[LESS INFO] 4 VIEWS | ADDED 12:49:00 08/12/09
What is IB Physics? Are you a student who is just about to start the course? This presentation is a 10-minute overview of the IB Physics course.

Episode #5: Uniform...
54 Views
04:46:00 06/29/09

The topic of this episode is Uniform Motion. What is an equation of motion? How does the equation of motion look like in the specific case of uniform motion? How d...

Episode #5: Uniform Motion

Added 06/29/09
54 Views

Episode #5: Uniform Motion

[LESS INFO] 54 VIEWS | ADDED 04:46:00 06/29/09
The topic of this episode is Uniform Motion. What is an equation of motion? How does the equation of motion look like in the specific case of uniform motion? How do we use equations of motion in solving problems? The answers, with examples, in this episode. You can also watch this episode on my blip.tv page and my youtube channel.

Discussion forum at...
3 Views
12:15:00 06/14/09

A discussion forum is now available at ibphysicshelp-community.net . Here you can find up-to-date information about the coming episodes, ask/answer specific physi...

Discussion forum at ibphysicshelp-community.net

Added 06/14/09
3 Views

Discussion forum at ibphysicshelp-community.net

[LESS INFO] 3 VIEWS | ADDED 12:15:00 06/14/09
A discussion forum is now available at ibphysicshelp-community.net . Here you can find up-to-date information about the coming episodes, ask/answer specific physics-related questions and find various resources (websites, books, etc.) that other students found useful in their study of physics. UPDATE: Due to lack of time for maintenance and relatively low forum activity I decided to close the discussion forum. For up-to-date information about this podcast and other useful IB physics resources follow my Twitter feed .

Episode #4: Types o...
145 Views
19:47:00 11/23/08

Uniform motion, uniformly accelerated motion, uniform circular motion, simple harmonic motion - what is the difference between all these types of motion? This epis...

Episode #4: Types of Motion

Added 11/23/08
145 Views

Episode #4: Types of Motion

[LESS INFO] 145 VIEWS | ADDED 19:47:00 11/23/08
Uniform motion, uniformly accelerated motion, uniform circular motion, simple harmonic motion - what is the difference between all these types of motion? This episode covers the most common types of motion one may come across while studying physics in high school. This episode is also available on my youtube channel and on my page at blip.tv .

Episode #3: Describ...
9 Views
06:28:00 07/10/08

If you want to describe the motion of a moving body, you have at hand three important physical quantities: speed, velocity and acceleration. How is each one of the...

Episode #3: Describing Motion - Speed, Velocity and Acceleration

Added 07/10/08
9 Views

Episode #3: Describing Motion - Speed, Velocity and Acceleration

[LESS INFO] 9 VIEWS | ADDED 06:28:00 07/10/08
If you want to describe the motion of a moving body, you have at hand three important physical quantities: speed, velocity and acceleration. How is each one of them defined? What's the difference between average and instantaneous velocity? The answers and more in this third episode. This episode is also available at blip.tv and on my Youtube channel.

« Previous 1 2 Next »

Quick Demo: Eddy current brake

Show: IB Physics Help Video Podcast

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Quick Demo: Eddy current brake
10/22/11

A spinning copper disc is slowed down when a magnet is brought near it. Note that copper is not a magnetic material. Eddy currents are induced in the disc due to the relative motion of the disc and the magnet. The magnetic fields associated with these currents have such a direction that they oppose the cause that created them in the first place (Lenz rule). As a result they oppose the relative motion between the disc and the magnet and hence the disc is slowed down.