RHR 1&2

The right hand rule helps demonstrate the relationship between conductor current and the direction of force. The first right hand rule for convertional current flow is used to determine the direction of current flow in a conductor. The conductor where you right hand's thumb is pointing at, is the direction of convertional. (positive current flow).

In the second right hand rule, the propose is to determine the direction of the magnetic field. The thumb point at the North -Pole.  

Notes - Magnetism p.582~589

● Magnetic Field is the repartion of a magnetic force in a region of a magnet.

●We use test compass to measure the magnetic forces within an area or object, instead of the test charge we used in electrostatics.

●Magnet attracts ferrous objects such as, pieces of iron, steel, nickel and cobalt.

●The magnet repel one another if both magnetic poles are north and north, or south and south ; The magnet attract one another if magnectic poles are difference(dissimilar). <North and South>

●The Domin Theory tells us that all large magnet are constitute by many smaller and rotatable magnet. Those small and rotatable magents are called dipoles. Dipoles can interact with other dipoles to close by.

● Magnetic Domin is created if dipoles are lined up.

●Oersted’s Principle is an important discovery made by Hans Christian Oersted. Oersted’s Principle tells that a circular magnetic field around the conductor is produced when charge moving through a conductor.

●There are two right- hand rules that help us to predict how magnetic force act. Right- hand rules are like physical formula because they allow us to take certain known factors and predict one unknown factor.

●The first right hand rule for convertional current flow is used to determine the direction of current flow in a conductor. The conductor where you right hand's thumb is pointing at, is the direction of convertional. (positive current flow).


●The second Right hand rule is to determine the direction of current flow within a coiled. The thumb point at the direction of the magnetic field within thr coil.

Notes from p.553~563

◎Electrical resistance is a material's opposition to the flow of electric current and it's measured in Ohms (Ω)

◎ Circuit with a boarder pathway and narrow pathway is different by the current flow, there're more current pass though a circuit with a boarder pathway than a circuit with a narrow pathway

◎The resistance of a conductor depends on things such as, its length, cross-sectional area, the material it is made of , and its temperature.

◎Series circuit is the circuit which the loads are connected one after another in a single path.

◎If two or more components are connected in parallel they have the same potential difference across their ends, that's parallel circuit and they are side by side.

←◎Georg Simon Ohm is the person  who discovered that V/I ratio was constant for a particular resistor. (Known as the Ohm's law)

◎ Kirchhoff's Current Flow us the total amount of current into a  junction point of a circuit equals the total current that flows out of that same junction.
 
             I(1) + I(2) + I(3) = I(T) = I(4) + I(5)

◎    Kirchhoff's Voltage Law is the total of all electrical potential decreases in any complete loop is equal to any potential increases in that circuit loop.                                             
                                                             Gustav Robert Kirchhoff →↑

◎There is no net gain or loss of electric charge or energy in any circuit with the laws of conservation of electric charge and the conservation of energy, these laws are corresponding to the Kichhoff's laws too.

※ R = Resistance   V = Volts (The potential Difference)  I = Amperes (Current flow)

The equation of calculating electrical resistance is                        

R = V/I                                                            

               

The equation of calculating voltage (volt) is
                                                                                                    V = IR


The equation of calculating Current flow (Amperes) is
                             I = V/R

The Prelab Table

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Energy ball activity - Question 1 to 12

※Can you make the energy ball work? What do you think makes the ball flash & hum?  
    YES,  we made the ball flash and hum by being part of the curcuit. We are the conductor(wires) and the ball is the resistance(light).

※Why do you have to touch both metal contacts to make the ball work?
 
    We become the conductor, the elctrons flow thougth in our body  and that's called "current flow". We have to touch both sides to make the circuit completed.

※Will the ball light up if you connect the contacts with any material?
  
    No, the ball won't light up with any material except conductor.
※Which materials will make the energy ball work?
 
    I thick that metals could make the ball works because metals are conductor, the electrons could flow thougth it.

※This ball does not work on certain individual. What could cause this to happen?
 
   I think the current flow only work with people who have moisture skin. People who with dry skin can't make the electrons pass thougth their body.
※Can you make the energy ball work with all 5-6 individuals in your group? Will it work with the entire class?

    Yes, it works with any number of people, the size of the circuit will be bigger if more people become part of the circuit.

※What kind of a circuit can you form with one energy ball?

    We can form the simple circuit with on energy ball. The electrons transfer thougth our body.

Energy ball : light
Group members : conductor

※Given two balls, can you create a circuit where both balls light up?
     Yes, it's possible to create a circuit with both balls light up, the name of the circuit is series circuit.
  

※What do you think will happen is one person lets go of the other person's hand and why?

   The current flow will stop and the ball won't light up. It just like the switch of  a simple circuit, one person lets go means that the circuit is not completed, so the electrons can't flow thougth the conductor.

※Does it matter who lets go?

   No, the current flow stops if anyone lets go in a simple circuit. It only matters who lets go in paralel circuit.

※Can you create a circuit where only one ball lights (both balls must be included in the circuit)？

   We can create a parallel circuit to make only one ball lights. As you can see in the picture below, the electricity can still suppy to the other light bulb if one is off.

※What is the minimum number of people required to complete this?
   I think one person is already possible to complete this.

Difference between series circuit and parallel circuit

 Series circuit is the circuit which the loads are connected one after another in a single path. If two or more components are connected in parallel they have the same potential difference across their ends, that's parallel circuit. The difference between series circuit and parallel circuit is that a parallel circuit has more than one path in the circuit, and a series circuit only has one way around it.

For additional information, you can watch the vedio below.

※Physics Tall Structure Challenge

                                                                           §The Physics of tall structures

"Higher the structure, lighter the top" The base of a tall structure should be wide and heavy, so it can support the weight on the top. The centre of gravity also has to be low. If the centre of gravity is to high, the structure might fall at any time.









§What makes a tall structure stable?

 The base of a tall structure is the most important part for the structure's stability. For example, while we are playing JENGA, what will happen if most of the blocks at the bottom are removed and what will happen if more and more blocks are put on the top?

                                      "It will fall"

So, a tall structure must have a wide and heavy base to secure the whole structure.

§What is the centre of gravity?
The centre of gravity (CP) is the average location of the weight of an object, it's equal to the center of mass.

notes on chapter 16 - p.544~552

-Circuit is an electrical device that provides a path for electrical current to flow

-Any power supply gas current flow which moves from the positive terminal(RED) to the negative trminal(BLACK)

-The power supply supplies a centain amount of electrical pontential energy

-Electric current involes electrons repelling one anthor and passing through a conductor

-The symbol "I", represents the rate of charge flow

-The energy delivered to the load depends on the potential and the current

-If the path is more difucult, there will be more opposition to flow

-Electrical resistance is a material's opposition to the flow of electric current and it's measured in Ohms

-There are more useful when the static state electrons are made to transfer energy

- The currennt flows in a single direction from the power supply through the donductor to a load is called DC(Direct Current)