In a nutshell, a
motor consists of a current carrying wire and a magnet. For the motor we build
in class, we attached bent paperclips to the poles of a battery. We fixed a
loop in the middle of the copper wire, and it rested on the paperclips.
When a current
runs through the wire, a force is felt from the magnetic field, which causes a
torque and then causes the motor to run. The reason a torque occurs is because
the charges are perpendicular to the magnetic field. If they were parallel,
there would be no force, no torque, and therefore no operating motor.
This is why we
scraped the wire on the top section (longwise facing the ceiling), so the
charges would be perpendicular to the magnetic field and cause a torque.
Even the most
complicated motors start with this simple model involving the magnet and wire. Motors
can be used to power drills, cranks, or any object that requires rotation.
CHARGES AND POLARIZATION
This video discusses charges, the different types of polarization, and Coulomb’s law. Watch to learn about how lightning works, and why balloons stick to walls after you rub them in your hair.
Please excuse the poor quality :/
ELECTRIC FIELDS AND ELECTRIC SHIELDING
→ Electric fields are areas around a charge that can have an influence on another charge
→ Electric shielding is when charges distribute evenly amongst each other, and the charges inside the field experience no force
The arrows around charges show which way the charge is pushing. The closer the lines are, the stronger the electric field.
Metal boxes act as electric shields. Metal allows charges to evenly distribute. The charges in the outside field are pulling the charges in the box with equal and opposite forces. Since the contents of the box experience no force or movement, they are safe.
OHM’S LAW AND ELECTRIC POTENTIAL DIFFERENCE
→Electric potential energy- energy that is stored within electric fields
→Electric potential and voltage are used synonymously
Both are measured in volts
→Ohm’s Law
Ohm’s Law deals with the relationship between voltage, current, and resistance
It is easy to confuse volts and voltage. Remember that volts are the same as electric potential (pe/charge or J/C)
Voltage causes current, and is the difference in electric potential.
What are capacitors?
→ Capacitors are two plates fixed with opposite charges. Charges are added to each side, and the electric field and energy increases between them. Energy then rushes from one plate to the next through a wire, and energy is released in the form of light. Capacitors are often used as camera flashes
CIRCUITS
In order to have a complete circuit, you must connect 2 uneven electric potentials to cause current to flow. Here are the two main types…
→Series
→Parallel
→Fuses
Fuses are added to parallel circuits (since they can have more current running through them), but are wired as a series.
When too much current runs through the circuit, the fuse will break. This will cut current from all devices to prevent fires, because too much current creates a lot of heat.
→Calculating current and resistance
