Now, young grasshopper, in order to become a master of the unit ELECTRICITY, there are a few things that you must know. In fact, these might be the top 10 things that you should know in case you may encounter obstacles or rather tests in your life. However, you must only use this knowledge for good.
1. the difference between conventional current and electron flow; conventional current moves from +ve to -ve and electron flow moves from -ve to +ve
2. equation for current: I = Q/t ; where I is current measured in amperes (A), Q is the charge in Coulombs (C), and t is the time in seconds
3. one electron is the equivalent to 1.6 x 10-19 C and one Coulomb is the equivalent to 6.25 x 1018 electrons
4. the difference between series circuits and parallel circuits (and possibly how it affects the world) *keep in mind that a circuit with both series and parallel circuits are called complex circuits
5. equation for potential difference: V = E/Q; where V is voltage/potential difference measured in volts (V), E is the energy or work in joules (J), and Q is the charge in Coulombs (C)
6. Ohm's Law and Kirchhoff's Law and their relationship --> with this you must be able to solve the CURRENT, VOLTAGE/POTENTIAL DIFFERENCE, and RESISTANCE in a circuit
7. how to add voltmeters and ammeters in a circuit; voltmeters are used in parallel circuits and ammeters are used in series circuits
8. equation for power: P = IV or P = V2/R or P = I2R; where P is power in watts (W) and R is resistance in ohms (Ω)
9. how to figure out the overall resistance when given a colour band resistor (recall: the gold or silver band should always be at the end to indicate the percent error and the last colour before the gold or silver band is the exponent of the power with a base of 10)
10. how to draw/make or read graphs and being able to calculate the slope! SLOPE = RISE/RUN (don't forget to have a detailed title and include labels for the axes with the units)
and that, my young grasshopper, is what you need to know for ELECTRICITY
Thursday, February 24, 2011
Concept Map
Although one may believe that a more visual method of studying would be helpful, I somewhat agree and disagree. I guess you could say it depends on the way you have studied in the past (whether or not you constantly used one method of studying and adapted to that method) or simply the type of learner you are. I think that this concept map is somewhat too confusing for me. Maybe using this concept map for a brainstorm or review of everything I've learned might be helpful, but for me, rewriting out what I've learned on a piece of paper or making cue card notes is best for me. However, I won't say that I completely think that this method is useless to me, but a new method that maybe I just need to get used to. Who knows, it might end up becoming my best studying method yet, but I guess I'll have to adapt to it first.
Saturday, February 12, 2011
Ohm and Kirchhoff
Ohm's Law
Georg Simon Ohm (1787-1854) found that the ratio Potential Difference (in volts)/ Current (in ampere) [V/I] was constant for a specific resistor. This means that even if more energy sources were added on to the circuit, the quotient of the potential difference divided by the current would be the same. This relationship is known as being directly proportional which is represented by the sign "α" (lowercase alpha).
V α I
What does directly proportional mean? It basically means that when one variable goes up, the other variable goes up as well, and when one variable goes down, the other variable goes down as well. In our case, the two variables are POTENTIAL DIFFERENCE (V) and CURRENT (I).
Furthermore, current is inversely proportional with resistance which means that when the current goes up, the resistance goes down, and when the current goes down, the resistance goes up. It is represented by the following:
I α 1/R
Ohm's law can be represented by the mathematical triangle:
(*note: when looking for the current, cover I and you are left with V/R, when you are looking for the resistance, cover R and you are left with V/I, and when you are looking for the potential difference, cover V and you are left with IR [multiply])
Kirchhoff's Law
Gustav Robert Kirchhoff (1824-1887) came up with the two laws about current and voltage.
Current: "The total amount of current into a junction point of a circuit equals the total current that flows out of that same junction."
Voltage: "The total of all electrical potential decreases in any complete circuit loop is equal to any potential increases in that circuit loop."
CURRENT (I)
SERIES
IT = I1 = I2 = I3 = … = In
PARALLEL
IT = I1 + I2 + I3 + … + In
VOLTAGE/POTENTIAL DIFFERENCE (V)
SERIES
VT = V1 + V2 + V3 + … + Vn
PARALLEL
VT = V1 = V2 = V3 = … = Vn
WITH OHM'S LAW AND KIRCHHOFF'S LAW IN MIND, Resistance can be solved mathetmatically using both laws.
RESISTANCE (R)
Georg Simon Ohm (1787-1854) found that the ratio Potential Difference (in volts)/ Current (in ampere) [V/I] was constant for a specific resistor. This means that even if more energy sources were added on to the circuit, the quotient of the potential difference divided by the current would be the same. This relationship is known as being directly proportional which is represented by the sign "α" (lowercase alpha).
V α I
What does directly proportional mean? It basically means that when one variable goes up, the other variable goes up as well, and when one variable goes down, the other variable goes down as well. In our case, the two variables are POTENTIAL DIFFERENCE (V) and CURRENT (I).
Furthermore, current is inversely proportional with resistance which means that when the current goes up, the resistance goes down, and when the current goes down, the resistance goes up. It is represented by the following:
I α 1/R
Ohm's law can be represented by the mathematical triangle:
(*note: when looking for the current, cover I and you are left with V/R, when you are looking for the resistance, cover R and you are left with V/I, and when you are looking for the potential difference, cover V and you are left with IR [multiply])
Kirchhoff's Law
Gustav Robert Kirchhoff (1824-1887) came up with the two laws about current and voltage.
Current: "The total amount of current into a junction point of a circuit equals the total current that flows out of that same junction."
Voltage: "The total of all electrical potential decreases in any complete circuit loop is equal to any potential increases in that circuit loop."
CURRENT (I)
SERIES
IT = I1 = I2 = I3 = … = In
PARALLEL
IT = I1 + I2 + I3 + … + In
VOLTAGE/POTENTIAL DIFFERENCE (V)
SERIES
VT = V1 + V2 + V3 + … + Vn
PARALLEL
VT = V1 = V2 = V3 = … = Vn
WITH OHM'S LAW AND KIRCHHOFF'S LAW IN MIND, Resistance can be solved mathetmatically using both laws.
RESISTANCE (R)
SERIES
VT = V1 + V2 + V3 + … + Vn
(using Ohm’s Law we know V= IR)
ITRT = I1R1 + I2R2 + I3R3 + … + InRn
(which can be written as)
ITRT = ITR1 + ITR2 + ITR3 + … + ITRn
ITRT = IT(R1 + R2 + R3 + … + Rn)
(IT can be crossed out, which is represented by the red)
ITRT = IT(R1 + R2 + R3 + … + Rn)
RT = (R1 + R2 + R3 + … + Rn
PARALLEL
IT = I1 + I2 + I3 + … + In
(using Ohm’s Law we know I= V/R)
VT /RT = V1/R1 + V2/R2 + V3/R3 + … + Vn/Rn
(which can be written as)
VT /RT = VT/R1 + VT/R2 + VT/R3 + … + VT/Rn
(Multiply by 1/VT in order to isolate R)
(1/VT) (VT/RT) = (1/VT) (VT/R1 + VT/R2 + VT/R3 + … + VT/Rn)
1/RT = 1/R1 + 1/R2 + 1/R3 + … + 1/Rn
VT = V1 + V2 + V3 + … + Vn
(using Ohm’s Law we know V= IR)
ITRT = I1R1 + I2R2 + I3R3 + … + InRn
(which can be written as)
ITRT = ITR1 + ITR2 + ITR3 + … + ITRn
ITRT = IT(R1 + R2 + R3 + … + Rn)
(IT can be crossed out, which is represented by the red)
ITRT = IT(R1 + R2 + R3 + … + Rn)
RT = (R1 + R2 + R3 + … + Rn
PARALLEL
IT = I1 + I2 + I3 + … + In
(using Ohm’s Law we know I= V/R)
VT /RT = V1/R1 + V2/R2 + V3/R3 + … + Vn/Rn
(which can be written as)
VT /RT = VT/R1 + VT/R2 + VT/R3 + … + VT/Rn
(Multiply by 1/VT in order to isolate R)
(1/VT) (VT/RT) = (1/VT) (VT/R1 + VT/R2 + VT/R3 + … + VT/Rn)
1/RT = 1/R1 + 1/R2 + 1/R3 + … + 1/Rn
Wednesday, February 9, 2011
Favourite Roller Coaster Design
Although I've been to a couple of amusement parks in my lifetime, the only one that I've been to recently and clearly remember is Canada's Wonderland. In terms of thrill, I'd have to go with Behemoth as my favourite roller coaster there, but I must give an honourable mention to Psyclone for it's ability to make me smile and laugh so widely that my saliva manages to escape my mouth. Yes, it is slightly, if not entirely, disgusting but I can't help it. However, in terms of design, I'd have to go with Wild Beast or Flight Deck.
No, there's nothing cool about Wild Beast besides the fact that it is made out of wood. It's just attractive to the eye in my opinion, but when you ride Wild Beast, I must say... it's not a pleasant feeling. It is extremely bumpy and you will feel nauseous (at least I do) and your head will hurt from the shakiness.
Flight Deck is another design I like simply because it has many curves and bumps and a loop or two (oh, and your feet get to hang during the ride). My descriptions are sort of weak and pathetic because I'm not exactly a roller coaster fanatic and I can't seem to think of descriptive adjectives, but I do enjoy riding them.
Here are some pictures of the roller coasters mentioned:
Behemoth
Psyclone
Wild Beast
Flight Deck
No, there's nothing cool about Wild Beast besides the fact that it is made out of wood. It's just attractive to the eye in my opinion, but when you ride Wild Beast, I must say... it's not a pleasant feeling. It is extremely bumpy and you will feel nauseous (at least I do) and your head will hurt from the shakiness.
Flight Deck is another design I like simply because it has many curves and bumps and a loop or two (oh, and your feet get to hang during the ride). My descriptions are sort of weak and pathetic because I'm not exactly a roller coaster fanatic and I can't seem to think of descriptive adjectives, but I do enjoy riding them.
Here are some pictures of the roller coasters mentioned:
Behemoth
Psyclone
Wild Beast
Flight Deck
Tuesday, February 8, 2011
From Battery to Circuit (Energy Transformation)
Currents have a continuous flow of charged particles moving through loads/resistors, conductors, and energy sources, but how in the world do the charged particles manage to continuously "jump" from the negative to the positive electrodes ("a conductor used to make electrical contact with some part of a circuit")?
The reason for this occurence is because there is an energy source, for example a battery, where chemical energy is produced. The battery continuously gives off these charged particles in order for the circuit to function but when battery "dies," it simply means that the reactants have been used up, therefore there is no more chemical energy to provide the charged particles into the circuit.
important terms: direct current (DC) and alternating current (AC)
question/comment/food for thought: I'm sort of confused with "conventional current" and "electron flow," and the textbook does not make it better because it keeps mixing the two terms together saying that current = electron flow. Not only that but conventional current is the movement from +ve to -ve... but what's moving if it's not the electrons!?!?!?!
The reason for this occurence is because there is an energy source, for example a battery, where chemical energy is produced. The battery continuously gives off these charged particles in order for the circuit to function but when battery "dies," it simply means that the reactants have been used up, therefore there is no more chemical energy to provide the charged particles into the circuit.
important terms: direct current (DC) and alternating current (AC)
question/comment/food for thought: I'm sort of confused with "conventional current" and "electron flow," and the textbook does not make it better because it keeps mixing the two terms together saying that current = electron flow. Not only that but conventional current is the movement from +ve to -ve... but what's moving if it's not the electrons!?!?!?!
Saturday, February 5, 2011
The Energy Ball
Looks can be deceiving as a simple, white ball that appears to be almost no different from a ping pong ball was, to my surprise, certainly more complicating than an air-filled, plastic ball. This ball is known as an energy ball and it demonstrates how a circuit works. This energy ball contains the batteries, as well as a flashing red light and a sound generator which produces a slightly irritating, one tone pitch. In order for this energy ball to function, it requires conductive matter or objects to close the circuit. Unexpectedly, just by touching one of the metal strips on the ball with one hand and the other metal strip with the opposite hand, it closed the circuit. Who would've thought that we would be able to conduct electricity and close the circuit? It was also possible to complete the circuit with other peers and even the whole class, as long as the circuit was closed by holding hands, or in our case, touching each other with our pinkies. Our group experimented with several other objects, using more than one energy ball, and different combinations of "circuit wiring." It was a fun and informational experience and a good opportunity to interact with other peers.
important terms: series and parallel circuits
question/comment/food for thought: In order for electrons to pass through the farther load (from the cell/battery/energy source) in a parallel circuit, it would take more time, right? I wonder... if the farther load was significanly distant (i.e.100 metres), would it be possible to see the difference of the further load lighting up slower than the closer one? Or would the speed still be undetectable to our eyes?
important terms: series and parallel circuits
question/comment/food for thought: In order for electrons to pass through the farther load (from the cell/battery/energy source) in a parallel circuit, it would take more time, right? I wonder... if the farther load was significanly distant (i.e.100 metres), would it be possible to see the difference of the further load lighting up slower than the closer one? Or would the speed still be undetectable to our eyes?
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