1. IB Physics 12
Mr. Jean
November 6th, 2013

2. The plan: Video clip of the day More on circuits
Looking through components

3. Potential Difference =Voltage=EMF
In a battery, a series of chemical reactions occur in which electrons are transferred from one terminal to another. There is a potential difference (voltage) between these poles.
The maximum potential difference a power source can have is called the electromotive force or (EMF), e. The term isn't actually a force, simply the amount of energy per charge (J/C or V)

4. A Basic Circuit All electric circuits have three main parts
A source of energy
A closed path
A device which uses the energy
If ANY part of the circuit is open the device will not work!

5. Electricity can be symbolic of Fluids
Circuits are very similar to water flowing through a pipe
A pump basically works on TWO IMPORTANT PRINCIPLES concerning its flow
There is a PRESSURE DIFFERENCE where the flow begins and ends
A certain AMOUNT of flow passes each SECOND.
A circuit basically works on TWO IMPORTANT PRINCIPLES
There is a "POTENTIAL DIFFERENCE aka VOLTAGE" from where the charge begins to where it ends
The AMOUNT of CHARGE that flows PER SECOND is called  CURRENT.

6. Current
Current is defined as the rate at which charge flows through a surface.
The current is in the same direction as the flow of positive charge (for this course)

7. There are 2 types of Current
DC = Direct Current - current flows in one direction
Example: Battery
AC = Alternating Current- current reverses direction many times per second. This suggests that AC devices turn OFF and
ON. Example: Wall outlet (progress energy)

8. Problem Solving Activity:
Who killed the Hindenburg?

9. The Hindenburg:
The pride of Germany and a wonder of it’s time. The zeppelin was nearly 3 football fields long and was the largest flying machine that had even been build.
The Hindenburg was landing on May 6th, As the crews started to tie down the drop lines it was noticed ripples in the fabric about one third of the way forward from stern.
Within 32 seconds the ship exploded, burnt and hit the ground.

10. Video:

11. Problem Solving Activity:
Who killed the Hindenburg?

14. Hindenburg:
The Hindenburg disaster took place on Thursday, May 6, 1937, as the German passenger airship LZ 129 Hindenburg caught fire and was destroyed during its attempt to dock with its mooring mast at the Lakehurst Naval Air Station, which is located adjacent to the borough of Lakehurst, New Jersey. Of the 97 people on board (36 passengers, 61 crew), there were 35 fatalities as well as one death among the ground crew.

15. The Hindenburg:
When the Hindenburg was landing the potential energy of the air was higher than the potential energy on the ground.
Because it was raining the ropes used to guide and land the craft acted as a wire transferring the electricity.
The CLOSED CIRCUIT caused an electrical discharge which caused the hydrogen to explode.

16. Random useless information:
Early on, before Led Zeppelin made it big, they were told that their music would go over like a lead filled Zeppelin. They changed the spelling of led to make sure they were not considered the first zeppelin.

17. Circuits: Brightstorm Basic Circuits: (Yelling Guy)

18. Ohm’s Law: V = IR V = Potential difference in volts (v)
I = Electric current in amperes (A)
R = Resistance in ohms (Ω)
1A * 1Ω = 1V

19. Resistance
Resistance (R) – is defined as the restriction of electron flow. It is due to interactions that occur at the atomic scale. For example, as electron move through a conductor they are attracted to the protons on the nucleus of the conductor itself. This attraction doesn’t stop the electrons, just slow them down a bit and cause the system to waste energy.
The unit for resistance is the OHM, W

20. Unit of resistance:
One ohm is defined as the amount of electric resistance that will allow one ampere of current to move through the resistor when a potential difference of one volt is applied across the resistor.

21. Example:
What is the resistance if a battery with 9.0V of potential difference causes a current of 0.45A to pass through a resistor?

22. Example:
What is the resistance if a battery with 9.0V of potential difference causes a current of 0.45A to pass through a resistor?

23. Resistors & Circuits: Brightstorm – Yelling Guy Resistors in Circuits