Steven's Physics: September 2010

Saturday, September 25, 2010

Right-hand Rule #1 and #2

First Right-hand rule (for conventional current flow) - Grasp the conductor with the thumb of the right hand pointing in the direction of conventional current flow. The curled fingers point in the direction of the magnetic field around the conductor.

Second Right-hand rule (for conventional current flow) - Grasp the coiled conductor with the right hand such that curved fingers point in the direction of conventional current flow. The thumb points in the direction of the magnetic field within the coil. Outside thte coil the thumb represents the North end of the electromagnet produced by the coil.

Pg 582 - 589

Magnetic field is the distribution of a magnetic force in the region of a magnet.

There are two different magnetic characteristics, which are labeled as North and South that are responsible for magnetic forces.

If you were to put North and North together they would repel one another, same goes for South and South. But if you were to put together North and South together they would attract with a force.

Ferromagnetic metals are certain metals that are not magnet (iron, nickel, and cobalt) which have an atomic structure that seems to make them strongly magnetic.

Domain theory - All large magnets are made up of many smaller rotatable magnets, called dipoles which can interact with other dipoles close by.

Oersted's Principle - Charge moving through a conductor produces a circular magnetic field around the conductor.

Electromagnet - a coil of wire around a soft iron core, which uses electric current to produce a magnetic field.

Right-hand rules - mapping the magnetic field with your right hand.

First Right-hand rule (for conventional current flow) - Grasp the conductor with the thumb of the right hand pointing in the direction of conventional current flow. The curled fingers point in the direction of the magnetic field around the conductor.

Second Right-hand rule (for conventional current flow) - Grasp the coiled conductor with the right hand such that curved fingers point in the direction of conventional current flow. The thumb points in the direction of the magnetic field within the coil. Outside thte coil the thumb represents the North end of the electromagnet produced by the coil.

Saturday, September 18, 2010

10 Points From Pg. 553-563

There are 2 things that affect the amount of current flow in a circuit which is...
1. The potential difference of the power supply
2. The nature of the pathway through the loads that are using electric potential energy

Resistance - a measure of the opposition to current flow

R = V/I

R - Resistance V - Volts (V) I - Current (A)

A thinner wire has a larger resistance rather than a thicker one, which one of the factors that differs between the amount of resistance. Another property could be the conductor for example Copper is a very conductible material.

Gauge number - The gauge number of a wire indicates its cross-sectional area.

Series circuit - a circuit in which laods are connected one after another in a single path.

Parallel circuit - a circuit in which loads are connected side by side

Kirchhoff's current law is the total amount of current into a junction point of a circuit equals the total current flows out of that same junction/

Kirchhoff's voltage law is the total amount of all electrical potential decreases in any complete circuit loopis equal to any potential increases in that circuit loop.

Monday, September 13, 2010

Prelab Chart

I did this on Word. I thought it would be simple but the problem was that I couldn't copy and paste it onto the blog so... I was totally lost. Luckily I asked a good friend of mine ;) Who helped me immensely by showing me the steps on how to counter this problem xD Thank you very much Friend (Y)

Sunday, September 12, 2010

Expensive Ping Pong Energy Ball & Parallel/Series Circuits! ;D

On Sept 10th, our class did an experiment involving a ping pong ball. From what Mr. Chung said, it was a very expensive ping pong ball... Which doesn't bounce. In my mind I'm thinking, "That seems stupid, if it doesn't bounce then what's the point?!" Then he put us into groups and gave us an envelope filled with smiley faces with questions on them. D:

I couldn't find any pictures of the balls we used so I used regular ping pongs.

Also. I forgot to take a picture of the experiment. Heh. <;D

#1. Can you make the energy ball work? What do you think makes the ball flash and hum?

Our group was able to make the energy ball work and function because they touched both sides of the metal that was protruding from the energy ball. The energy ball was able to flash and hum because our bodies completed the circuit.

#2. Why do you have to touch both metal contacts to make the ball work?

If you do not touch both ends of the metal contacts then the circuit will be incomplete and thus not making the energy ball glow or hum.

#3. Will the ball light up if you connect the contacts with any material?

We were unable to find anything metallic that can bend to touch both ends of the metal contacts and we kept on accidentally touching the metal contacts so we weren't sure if the energy ball glowed due to the metal or our touch. What we did find was that water can be used to make the ball light up by having both ends of a water stream touching the metal contacts.

#4. Which materials will make the energy ball work?

In theory metal should be able to make the energy ball work, but we weren't able to test our hypothesis because we didn't have anything that can touch both ends of the metal contacts at the same time. Water is also capable of making the energy ball glow.

#5. This ball does not work on certain individuals. What could cause this to happen?

Certain individuals may not be as hydrated as others since water can be used to transfer energy. Another hypothesis can be that someone may be wearing a rubber suit? It won't be able to conduct electricity and will not be able to complete the circuit.

#6. Can you make the energy ball work with all 5-6 individuals in your group? Will it work with the entire class?

Yes, the ball was able to work with all members involved in the circuit. The energy ball should work with the entire class as the energy is being transferred through each individual. If the the circuit is incomplete then the energy ball will function.

#7. What kind of a circuit can you form with one energy ball?

A simple circuit can be formed with one energy ball.

#8. Given two balls, can you create a circuit where both balls light-up?

Yes it is possible to have both balls light up.

#9. What do you think will happen if one person lets go of the other persons hand and why?

If someone were to let go then the circuit will be incomplete which would then make the energy balls nonfunctional. The reason why is because the connection was disrupted when someone loses contact with someone in the circuit.

#10. Does it matter who let's go?

If our group was rearranged differently then it would matter (e.g. Switch) but if the circuit is like a circle then no matter who let's go, the circuit will be incomplete.

#11. Can you create a circuit where only one ball lights?

The probable answer was yes but I'm not sure because when we had a group of 4 one ball was able to light up but with the addition of Alex Liu... None of them worked. From that experiment I assumed the energy dissipates with each person but when doing the entire class circuit it wasn't so.

#12. What is the minimum number of people required to create a circuit where only one ball lights?

The minimum, number of people required to create a circuit where only one ball lights is 3 people. 2 people keep in contact with the energy ball while the third keeps in contact with them. If one of the 2 people disconnects from the energy ball then that would cause one ball to function while the other does not.

The Difference Between a Parallel and Series Circuit

Series Circuit

Parallel Circuit

Series Circuit - where there is only one path from the source through all of the loads and back to the source. This means that all of the current in the circuit must flow through all of the loads. From http://lansing.apogee.net/foe/fcsps.asp

Parallel Circuit - a circuit in which there are at least two independent paths in the circuit to get back to the source. In a parallel circuit, the current will flow through the closed paths and not through the open paths.

From http://lansing.apogee.net/foe/fcspp.asp

Thursday, September 9, 2010

Newspaper Structure Activity

Here is a picture which depicts the pride and joy of hard work and passion due to 3 very important individuals. Namely Anusha, Kevin and of course Steven (me ;D).

Though the tower had a... Ummm... Slight bend in it if you will ;P it was still able to stay upright even though it was teetering on collapse due to the slightly heavier top. Luckily our group decided on making a sort of tripod for the base which was made up of rolled up newspapers and taped together (very badly xD but it stood strong).

Unfortunately we did not have the best tower in the class but give us some credit! We finished first! Doesn't that count for something?! ANYTHING?!

Anyways we could have cut down the height of the tower by shaving off some of the upper parts so we could use those pieces of newspaper to further stabilize the base of our tower and decrease the amount of stress that was causing the bend in our tower.

Even though the we lost to a group that was giving us the evil glare O.o. We still managed to make what we had and enjoyed every second of it.

Unfortunately it was sort of bitter sweet. Before I was able to get a group photo with my fellow members. Someone (I'm not naming who) turned the tower into scrap paper... -_-

I'll see guys on the next post but by then I'll already be halfway planning my revenge on that certain person.

Congratulations to my fellow competitors, it was a worthy competition ;)

Notes on Current Electricity

An electric current is a flow of charge. A simple example can be such things as a pipe that is carrying water but the difference between the pipe and the electric current is that it carries electrons.

Current is given the symbol "I" to represent the total amount of charge moving past a point in a conductor divided by the time taken.

I=Q/t

Ampere (A) is equivalent to one charge of coulomb moving through a point in a conductor every second.

Negatively charged electrons will always repel one another which causes it to create a current flow.
http://www.fortunecity.com/greenfield/eagles/180/current.html as shown in the site.

The measurement of current can be done with an ammeter (current-measuring device) by attaching it to the current flow. By doing so you'll be able to measure the DC or direct current which travels in a single direction from the power supply to the conductor.

The electric potential difference is the potential energy for each coulomb of charge in a circuit which can be shown in this simple equation.

V=E/Q

E= the energy required to increase electric potential of a charge

Q= charge

The energy that can be transferred by charge flow would equal this equation.

E=VIt

E=Joules V=Volts I=Amperes t=Time in seconds

A voltmeter can be used to measure between any two points but must be connected to a parallel. Which is a circuit in which loads area connected side by side.

Everything contains some sort of energy which can be exchanged easily from produced forms. Devices are able to harness this energy to form different types of electrical potential energy which may be chemical, mechanical, thermal, or light energy.