Blog,

I do not know why there is a big blank space between the first and second post.

Energy

There are numerous types of energy that can be transformed back and forth. These include thermal, heat, gravitational potential, elastic potential, chemical, electric, magnetic, and radiant energy.Out of these, the first two, thermal and heat are part of kinetic energy. They are the energy of motion. The faster an object moves, the more energy there is. The rest of the energies is potential energy. This is the energy that is stored or energy that is not in use at the moment. They have the potential to do "damage" in the future.
Examples of kinetics would be if a ball moved faster or a person runs faster, they would have more kinetic energy.
Potential would be if a boulder was at the top/tip of a mountain and it was about to drop, it would have a lot of potential energy, but there is no kinetic energy since it is not moving.

Cannon

Today, our class received an assignment on cannons. Basically we need to build a cannon from a maximum of 5 pop cans and try to see which one will go the furthest. I do not know how we are supposed to make a base for the cannon if the tube thing is going to use 3 cans and only 2 left for the base. The cannon will be fueled with ethanol and the ball will be two Styrofoam cups taped together. Hopefully the cannon that we build will work.
Here's a HANDDRAWN picture of what the cannon will look like, (copied from the sheet).

Newton

We began learning about Newton's laws and 4 different types of problems.
Equilibrium problems is when the object is not moving and the forces are equaled out.
Angles are included. Usually it's an object in the air that's connected to beams or strings. This needs to counter gravity to make the net force 0.

Incline is when there is a slanted surface. Usually to calculate how fast the object is going and how much force is in the x direction. The fbd needs to be shifted and gravity needs to be changed into x and y. There is usually friction force which is part of fx.

Pulleys, there are usually no friction. Tension is the same. It usually calculates how fast the object is accelerating and the force on the string that is connected to the two objects.

Finally, for trains, it is similar to just making the pulleys into a straight line. There is a force applied and then the person needs to find out the tension between the cars. The force applied is the most then decreases after each tension along the train. There is usually friction. There is no Fy.

I BALANCED AN EGG

Woo, it's Monday Nov, 8 today. I was bored, so I went to try balancing eggs to get ready for tomorrow challenge. And..I actually did it. Took around 10 minutes for the first one. Pictures below.

Then I was able to balance two. 

 After two I just gave up and went to do my homework.

Projectile Motion

To calculate projectile motion, we need to use sin, cos, and tan. Usually there is an angle. The question usually asks about the time of flight and the horizontal distance from the start.
The big five equations are used to solve these.

Here is an image showing what each part is equal to. Theta is the angle of the path to the horizontal. horizontal distance is range in x and the height is in y.

Rollercoasters

For our isp we get the option to build a roller coaster out of common day materials. This project is due by January. It will be entered into the WonderCoaster Contest at Wonderland. Here are some previous winning roller coasters in 2009.

ANTcity
First place for Technical from A.Y. Jackson

Mario Speedway
First place for Artistic from Richview CI

Calculating Vectors

To add vectors, you start from the beginning and draw a line to the end. This will create a triangle. By using Pythagorean Theorem, the length of the line can be obtained, which will be the scalar value of the vectors. To find the direction, trigonometry is used.

To calculate the angle of the vector, it would be 90-theta. To calculate theta, tan^-1 (vertical/horizontal) is used.

Big 5 Equations

1. d=1/2(v1+v2)t
2. a=(v2-v1)/t

To derive equations 3 and 4, v needs to be substituted from one equation into the other.
a=(v2-v1)/t
v1=v2-at
Substitute v1 into equation 1
d=1/2(v2-at+v2)t
d=1/2(2v2-at)t
d=v2t-(1/2)at^2 <=== Equation 4

v2=v1+at
Substitute v2 into equation 1
d=1/2(v1+v1+at)t
d=1/2(2vt+at^2)
d=vt+(1/2)at^2 <====Equation 3

To derive equation 5, t needs to be substituted.
a=(v2-v1)/t
t=(v2-v1)/a
Substitute into equation 1
d=1/2(v1+v2)(v2-v1)a
d=1/2(v2^2-v1^2)a
2ad=v2^2-v1^1
v2^2=v1^2+2ad

Distance and Velocity

-The distance is calculated by the area of the time in seconds and the velocity in the velocity time graph

Position and Velocity Time Graphs

Graphs

Position vs Time

In this graph, the person walked stayed for 1 second

Walked away for 2.5 m in 2 seconds 

Stayed for 3 seconds

Walked 0.75 m towards in 1.5 seconds 

Stayed for 2.5 seconds

Person walked away 1 meter for 3.5 seconds

Stayed for 2.5 seconds

Walked away 1.4 m for 3.5 seconds

Walked towards 1.5 m for 3 seconds

Stayed for 1 second

Walked towards 1 m for 1 second

Stayed for 2 seconds 

Walked away 2.5 m for 3 seconds

Velocity vs. Time

Stayed for 2 seconds 

Walked towards at 0.5m/s for 3 seconds

Stayed for 2 seconds 

Walked backwards at -0.5m/s for 3 seconds

Walked faster and faster from 0 m/s to 0.5m/s for 4 seconds

Walked at 0.5m/s for 2 seconds

Walked backwards at -0.4m/s for 3 seconds

Stayed for 1 second

Walked at 0.4 m/s for 3 seconds 

Walked backwards at -0.4m/s for around 4 seconds 

Stayed for 3 seconds

This is a video of the motor Kevin S and I made

Electric Motors

Today and yesterday, our class built motors out of simple components. We were supposed to use 4 inch nails, a cork, wires, a wood board, aluminum brushes, wooden stick as an axle, small nails for commutators, and paper clips as bearings. Two nails were supposed to be spaces 3 cm from one another and 5 cm from the other two. The wooden axle penetrates the cork and placed on the paper clip bearings. The brushes were held onto the board with thumb tacks between the bearings and the nails. The brushes were supposed to touch the commutator pins. When the pins touched the brushed the current flow reversed, so the cork would keep on spinning. One side just keeps on pushing up and the other just keeps on pushing down. The south side and north side of 2 magnets are on both sides to repel the magnetic field created by the wires. Most groups' worked better the first day than on the second day.

Right Hand Rule

The right hand rule is able to help people determine which way the current is flowing in an electromagnet and predict the direction of electromagnetic force.
RHR #1 for conventional current flow
The person grabs the conductor using their right hand with their thumb pointing in the direction of positive current flow. The direction that the hand wraps around the conductor is the direction of the magnetic field.
RHR #2
The right hand grabs the coil so that the fingers and pointed in the direction of conventional current. The thumb points to the North end of the electromagnet.

Magnetic Force Pg. 582-589

-a magnetic field is the distribution of a force in the magnet
-there are two different magnetic characteristics, north and south
-similar magnetic poles will repel one another, and different poles attract
-a test compass is used to map a magnetic field
-the Earth acts like a magnet, it's magnetic field is produced because of the flow of hot liquid metals beneath the crust
-magnets does not only attract magnets, but they also attract metals that are not magnets, like iron, nickel, and cobalt, which are called ferromagnetic metals
-all magnets are made up of many smaller and rotating magnets, called dipoles, which can interact with other dipoles close by and when the dipoles line up, a magnetic domain is produced
-Oersted's Principle states that charge moving through a conductor produces a circular magnetic field around the conductor
-there are many right hand rules, the first one is where the right hand holds the conductor with the thumb pointing in the direction of positive current flow
-the second rule is when a coiled conductor is held in the right hand so that the curved fingers point in the direction of positive current flow, the thumb points in the direction of the magnetic field within the coil
-electromagnets have a strong magnetic field and produces a lot of magnetic force

Resistance Ohm's Law

-The electrical resistance is the measure of the opposition to flow
-The resistance of an object can be calculated from dividing the voltage by the current
-The Greek letter Omega, Ω, is used to symbolize ohm
-There is a resistance of 1 ohm when 1 amp of current flows with a potential difference of 1 volt across a resistor.
-Every object has a resistance, the amount depends on the material's resistivity, the length of the material, and the cross sectional area
-The formula to calculate the resistance of a conductor is R=p(L/A). R is the resistance in ohms, p is the resistivity of the material in ohms x meters (calculated in lab results), L is the length of the material in meters, and A is the area of the cross sectional in m^2
-Conductors are able to become superconductors at very low temperatures, absolute zero which is 0 Kelvins equivalent to -273.15 degrees C
-To calculate the resistance within a series circuit, the resistance from all of the resistors is added together
-To calculate the overall resistance in a parallel circuit, 1 over the resistance of each resistor added together 1/Rt=1/R1+1/R2+1/R3+....+1/RN
-Three way light bulbs has two lights inside in a parallel circuit. It can light up one light, the other light, or both at the same time.

Prelab Table

Name	Symbol	Unit	Definition
Voltage	V	V	The energy that is lost between two points.
Current	I	A	The flow of charge.
Resistance	R	Ω	The measure of the opposition to flow.
Power	P	W	Rate at which work is done.

Circuits

Well, today in class, we were able to experiment with a special "ping-pong ball" that was able to light up and hum. I guess that within the ball there was a open circuit because it needed to be connected to work. The class separated into groups and needed to complete 12 challenging questions.
The Q & A's are below.

1. Can you make the energy ball work? What makes it flash and hum?
Everyone within the group were able to make the ball work by touching the 2 metal plates on the exterior of the ball at the same time. Human skin is a conductor similar to metal, so when we connected the circuit the current flowed from one of the contacts through our body into the other contact.

2. Why do you have to touch both of the metal contacts?
Both metal contacts need to be touched for it to work because the circuit needs to be closed/completed.

3. Will it light up if you connect it with any other material?
It will not light up with every material, only conductors and semi-conductors. The ball worked when I connected both contacts to a metal faucet, but it did not work when I connected them with plastic pens.

4. What materials will make the ball work?
Metals would be the best materials to make the ball work because they have free electrons to transfer the energy faster. The most conductive materials would include silver, copper, and gold.

5. This does not work on an individual. What causes this to happen?
For the toy ball to work, the individual needs to have moist skin. Withing that moisture, there are metals such as salts which contains electrons that can transfer the energy freely. If the skin is very dry, there will be less contact with the metal plates.

6. Can the ball work with 5-6 people or the entire class?
In our group, we created a circuit of 4 people with our fingers and one person touch one of the contacts and the other person touched the other. The ball lighted up and hummed.

7. What circuit can you form with the ball?
The circuit that we formed was circuit in series.

8. Can you create a circuit for 2 balls?
We created a circuit with 2 balls by combining two groups together. Both of the balled lighted up when the 4 people touched their fingers to the metal contacts.

9. What will happen if one person lets go of the other's hand? Why does it happen?
When one person let go of another person's hand the ball stopped flashing and humming. When they let go, the circuit changed from closed to open therefore creating an incomplete circuit.

10. Does it matter who lets go?
It does not matter who lets go because when one part is disconnected the entire circuit will stop working.

11. Can there be a circuit of two energy balls where only one ball lights up?
Yes, there can be a circuit of two energy balls where only one lights up. The circuit is called circuit in parallel.

This really bad drawing kind of shows how to make one out of two balls light up within a circuit. The objects are on both sides of the parallel circuit. They both have power supplies. The resistors are placed right before the batteries, making the balls work only after the electric current flows through the circuit. In the diagram, the circuit is disconnected on the left top side stopping the current of the left ball, but on the right side, the circuit is still connected.


12. What's the least number of people for this to work?
I think that the least number of people needed for this to work is actually 1. Each hand touches 1 contact on each ball, this would create a parallel circuit. When a finger is removed from one circuit, the other one would still work by passing the electric current through the body and into the other hand.

*Additional*
The question isn't really that specific. After thinking about it a bit more, the least amount of people needed for this to work is none because, we could just connect 3 metal wires to the ball for it to work. Two connecting one contact from each ball and one in the middle that connects the wires to make it a parallel circuit.

Series and Parallel

In a series circuit, the loads (eg. light bulbs) are connected in a single path. When a part of the circuit is disconnected, the entire connection cease to work. A great example of circuit in series would be Christmas lighting, they are connected one after the other.

In a parallel circuit, there are more than one resistor and multiple parallel paths for charges to move through. These are placed side by side, so if one of the loads in the circuit is broken, the charge will stop moving through that path, but continue to pass through the others. This type of circuit is used everywhere. When somebody turns off the television, it wouldn't turn off all of the electricity in the house.

A video about the circuit ball experiment

http://www.youtube.com/watch?v=pgT_9a5jMqM

Physics of Tall Structures

Yesterday, in Physics class, the activity was to build the tallest structure out of newspaper and some tape. My group members came up with the idea of crumpling up paper to make a "small" base and thought that it would actually support the weight of the entire building.It was one of the most ridiculous designs ever. In the end, as I expected, the center of gravity for the structure was too high and the height needed to be shortened so it doesn't fall over by itself. Our's was the shortest.
The best building design would be to make a triangular/rectangular pyramid at the bottom with rolled up newspaper (as other groups did). After that, roll around 2-3 full pages and tape one on top of the other. The base should be able to sustain the weight of the structure still. Above that, the newspaper needs to be ripped/cut into smaller pieces which would be made into prisms, (triangular or rectangular and simple). A full page of newspaper could create a length of maybe 2 meters, saving materials and making the top very light. The reset of the paper can be user to add supports to the base. This would make the center of gravity very low therefore it wouldn't topple over that easily.

Circuit Symbols

http://www.utc.edu/Faculty/Tatiana-Allen/devices.html

Current Electricity Notes

Notes on Pg. 544-552

• Electric current involves electrons repelling one another and passing through a conductor
• The flow of charge is called electric current
• One ampere is one coulomb of charge moving through a point in a conductor every second
• Current is a flow of negatively charged electrons repelling one another, so current moves from negative to positive
• An ammeter is a device that measures the current
• In direct current, the current flows in a single direction from the power supply
• In alternating current, the current flow reverses often
• The path of a circuit is called a current
• Potential difference between two points in a circuit can be measured using a voltmeter
• The electrical potential energy for each coulomb of charge in a circuit is called the electric potential difference

Formulas

Electric Current

Name                                                  Symbol                                            SI Unit

Current                                                      I                                                  A (amperes)

Quantity of Charge                                     Q                                                C (coulombs)

Time                                                          t                                                  s (seconds)
1 A=1 C/1 second
It is the rate of electric charge flow over a period of time. 

Electric Potential Difference

Name                                                Symbol                                             SI Unit

Electric Potential Difference                     V                                                   V (volts)

Electric Potential Energy                      W or E                                              J (joules)

Quantity of Charge                                  Q                                                  C (coulombs)
1 V=1 J/1 C