Motors

 A motor consists of a current carrying wire and a magnetic field. 

In class, we made a motor out of a battery, a rubber band, paper clips, a rubber band, a copper wire, and a magnet.

In the motor, the battery created a current that moved through one of the paperclips, onto the copper wire, and to the other paper clip (on the other side). This made a complete circuit in which current was able to flow. 

The battery supplies a current while the magnet supplies a magnetic field (b). The rubber band holds the paper clips in place and the paper clips allow the current from the battery to move to the copper wire. The paper clips also allow the wire to turn. 

 The copper wire has to be scraped on one side so that the wire will feel a force. The wire needs to be scrapped at the point of the paper clips to allow current through. If not done correctly, the wire will fail to make a complete circle when trying to spin. 

The current carrying copper wire feels a force because it is in a perpendicular position to that of the magnet (on the battery). This force causes torque, thus, the wire will rotate and spin around. 

 This small battery could be used for a fun little fan or a small car for Stuart Little. 

Electricity 

-Moving charges through a wire.

positive charges (+) = protons

negative charges (-) = electrons

In order for something to be charged there must be more of one charge than the other. For example, something that is positively charged has more protons than electrons. Something that is negatively charged has more electrons than protons. However, when there is an equal number of protons and electrons it would become neutral. 

It is important to remember that charges that are alike will repel and charges that differ will attract. 

There are three ways that something becomes charged: induction, friction, and contact. 

In friction, the electrons are stolen. Contact transfers electrons. Induction charges without contact. 

When you take of a sweater, your hair stands up because of friction. The sweater rubs up against the hair and steals electrons through friction. The sweater then becomes negative and hair becomes positive.

We know that because like charges repel, the positive hair strands repel each other and stand up.

Friction also causes clothes to stick together in a drier. This is because the clothes rub together, creating friction. Some clothes gain electrons becoming negative, while others become positive. Since opposite charges attract, the clothes with stick. This is where drier sheets become useful as they absorb electrons and make the clothes positive and repel each other.

Induction is what causes lightening. The clouds rub together and become charged through friction. The ground becomes

positive through induction (a cloud is negative). The cloud’s negative charges and ground’s positive charges leap towards each other through the air and the pathway may become completed. If this happens, it will release heat, light, and sound, creating lightening.

Because lightening produces heat, it also causes fires. In order to prevent this, lightening rods are placed on buildings as lightening is attracted to pointy objects. If the lightening were to strike the rod, it would run the charges along the building and into the ground. This keeps the building safe.

            Polarization is when the charges within an object separate, creating both positive and negative sides.

For this reason, plastic wraps stick to ceramic or glass bowls and not metal ones. When a plastic wrap is removed from the container, it is charged by friction and becomes negative. When it is brought near the bowl, the bowl’s protons attract and the negative charges move away. Thus, it becomes polarized. The plastic wrap sticks because opposite charges attract. We know this because of Coulomb’s law which states that the smaller the distance, the greater the force, and the greater the distance, the smaller the force.

We know this because F=kq1q2/d²

Electric Fields are areas of influence around a charge.

It looks like this when drawn. The arrows represent the direction a positive charge will be forced. When you have an electrical charge of 0, the charge experiences no force. An electronic encased in metal is safe because of electric shielding. When the electronic is inside the metal box, its electric field is 0, feeling no force. Metal allows charges to spread out evenly, and the charges in the box will pulled in one direction while having equal and opposite forces pulling them in the other direction.

Capacitors are two oppositely charged plates.

 For example, when you take a picture with a camera, two oppositely charged plates that are not connected. When charges are added to the plates it increases the force between them. This increases energy of the electric field. Energy rushes between the plates and is released as light. The flash is brief because of the time the process takes.

Electric Potential energy is the energy in electric fields.

Voltage is the difference in electric potential. Voltage=PE/q

Volts (V) are electric potential. 

Current (I) (measured in Amps) is caused by voltage and is energy carried through wires with charges. There are two types of currents: Alternating Currents (AC) and Direct currents (DC). In AC the electrons move back and forth (a dance move of sorts).DC moves in one direction.  

Resistance (R) (measured in ohms Ω) is the ability for current to flow through a wire. For example, a light bulb with a high resistance is long, narrow, and hot. Low R is wide and short.

There are two types of circuits: Series and Parallel. Series normally has dimmer bulbs if one is added, low current, and a greater R. When one bulb goes out, the rest of the bulbs in series stop working. Fuses are wired in series. The fuse will burst if there is too much current flowing from the wall. The fuse prevents fires and keeps the house safe. Parallel has a lower resistance and a high current.The brightness remains the same if more bulbs are added. They all continue working if one burns out. 

If you were figuring how much money it would cost to run a 40 watt light bulb connected to 160 Voltage source for an entire month and it costs .10 cents per KW hour, how much would it be?

there are 720 hours in a month

40 watts becomes 0.4 KW

(0.4)(720)= 288 KW Hours

288 * 0.10= $28.80

Ohm's law:

I=V/R

Meaning that current is directly proportional to voltage while being inversely proportional to Resistance. 

Current is affected by both voltage and resistance.The less current there is, the more resistance it will have, and the more current, the less resistance. It can be altered by change in width, length, and temperature. 

P=IV

Electric Potential= PE/q

When a light bulb burns out, the filament is cold with decreasing resistance. Thus, the voltage and current increases. When a lot current flows from the wall, it produces a lot of heat and causes the light bulb to burn out.

When you plug an American appliance to a European outlook, it is very hazardous. American outlets are built with a lower resistance and lower voltages. Where as European outlets have high voltage. When you plug in the American device to the European, it is given more current than it is able to process- causing fires.

Thanks for reading!