We began this unit of Electricity
by learning how a circuit works. We learned that a circuit to be complete it
must travel from a high voltage to a low voltage. Also, the circuit needs to be
closed or else the circuit will not be complete and will not carry the current
and there will be no electrical flow. This is why when a light bulb filament
breaks; there is no light afterwards. We learned a great example of how current
and circuits work. We learned that the
electrical shock you receive such as when you touch an electrical fence is
actually caused by the flow of current going through your body and into the
ground. If you stood on an insulator or jumped when you touched the circuit,
the current would not be able to go into the ground and thus the circuit would not be complete
and you would not receive an electric shock.
After this, we learned about charge
and the types of charge, such a positive, negative, and neutral charges. After
understanding that like charges repel and opposite charges attract we then
learned about the transferring of charges. We learned there were three main
methods of transferring charges were direct contact, friction, and induction.
We learned about how induction creates lightning storms, as the molecules
within the cloud become negatively charged, and cause the positive protons in
the ground to rise. This creates a pathway for lightning to form.
Next we learned about polarization
or the separation of charges within an object. For instance, if a negatively
charged balloon comes near a neutral wall, the attraction between the negative
and positive ions will cause the wall to become polarized, yet still neutral.
However, this introduces a new law called Columb’s law which states that the
force between charges is inversely proportional to distance squared or
otherwise know as Columbs
Law: K(q1)(q2)/d2. This is why electronics are placed in metal containers,
because according the columbs law the magnetic charges will be equal and
opposite to each other created functional balance within the hard drive.
Next we learned about voltage which is the
difference in potential energy it is also defined by the formula V=PE/Q. We
learned that voltage creates current and that voltage is not necessarily
dangerous but current is. Current is the transfer of energy or is dictated by
ohms law as I=V/R. R is resistance or an object’s ability to resist current. Resistance
is affected by temperature as well as length and thickness of an object. For
instance, a light bulb will not blow if its been on a while because its
resistance increased with the heat. It will blow when its been just turned on
as the filament is cooler and cannot have the resistance to withstand a strong
current. We then learned there are two types of current direct current and
alternating current. We learned that most households have alternating current.
Finally we concluded learning about series and parallel wiring. IN series all
the outlets share the same current and circuit while in parallel they are all
independent of each other. Most houses are wired in parallel because that way
if you shut one appliance off it does not ruin the rest of the circuit and
everything can work independently of everything else. However, it is important
to have a fuse wired in series to control the parallel since with each
appliance added you create a stronger current and a weaker resistance so to avoid
potential fires the fuse will cut off the circuit ending the potential threat.
All in all this chapter has been one of the longer
ones considering the many interruptions and other factos. My biggest issue with
the chapter was retaining the information and preparing for the quizzes. I
believe I overcame such obstacles by just becoming more familiar with the
topics at hand and trying to review ass much as possible I did notice that the
test did seem much easier. For next unit, I hope to learn the information
before the quizzes instead of after the quizzes and hope to be more dependent
on my notes and the given lectures.
