Charged: When an object is charged, it has either more electrons or less electrons than it has protons, and it will therefore exert a force on other charges in the world around it
Polarization: When a charged object approaches a neutral object (or another charged object), the charges within the second object separate as to have the opposite, attractive charges be closer together, and the like, repelling charges further away from each other.
Different ways to charge an object:
Contact
Friction
Induction
Electric Fields:
An electric field is the area of influence that a charged object has on other objects around it
Vector arrows point in the direction that a positive charge would be forced
A negative charge will be forced in the opposite direction of these vector arrows
Farraday's Cage
A farraday's cage is something (usually a metal casing) that disperses charges equally around it so that any object inside will feel Zero Net Force on it. This can be seen in computers or other valuable electronics that are protected with a metal case. This is also called Electric Shielding
Voltage:
Voltage is the difference in electric potential between two points. the formula for voltage is V=Change in PE/q (charge)
Voltage in household appliances is fixed at a certain, unchanging value.
Coulomb's Law
Coulomb's law states that an object's force is equal to a constant, k, times charges one and two all over distance squared (F=kq1q2/d^2)
This is how we can explain a balloon sticking to a wall after being rubbed in one's hair, and also how we can explain part of how plastic wrap sticks to a plastic bowl.
Lightning:
Lightning works by first having negatively charged clouds that get close to the ground. This negative charge polarizes the neutral earth and brings the positive charges closest to the surface of the earth. When the attractive force between these opposite charges gets to be too much (along with a little added energy), a pathway is formed from the cloud to the earth, and the charges rush to the earth creating the flash that we all know.
We use lightning rods to have lightning strike the rods which are more conductive, then the charges travel down a direct path to the Earth, rather than going through the house and leaving little to no damage.
Circuits:
Circuits can be as simple as someone touching an electrified fence while standing on the ground, or they can be as complicated as the wiring within buildings.
For charges to flow, a circuit must be complete with no gaps.
Types of Circuits:
Series: more appliances= same current but "dimmer appliances", one appliance stops working= whole circuit stops
Parallel: More appliances= more current, one appliance stops working= rest keep working
Current: the flow of charges in a circuit (amps)
Resistance: the factor in electrical circuits that inhibits current (ohms)
Ohm's law: V=IR (Voltage= current x resistance)
Power= Energy/ time, Voltage x Current
Fuses protect household appliances and the wiring of a certain area. This works by having the conductor that bridges the two sides of the fuse being rated for a certain current, when the current gets too high this conductor melts and therefore switches the circuit off. Fuses are wired in series so that when they melt, the whole circuit turns off. This protects wiring as when current rises too high the wires start to combust which is dangerous.
As heat rises, current decreases, resistance increases. This is what causes light bulbs to blow right as you turn your lights on.
My effort and Problem solving skills this unit
My effort in this class has been fairly consistent for this unit, asking questions when I struggled with a concept, and learning to the best of my ability. I did not encounter too many problems that I struggled with. This unit has answered a few questions that I always had when people discussed electricity and how it works in houses and other buildings.
My goal is to keep strong effort and try my best to keep up strong grades to end the year.
