Science: Magnets, Electricity, etc.
What is the equation to find total resistance for a parallel circuit?
1/R= 1/R1+ 1/R2 + 1/R3...
What is magnetism?
A force created by magnets
What do fuel cells, batteries, and solar cells have in common?
All sources of direct current
What is an electric field?
Area of electric force around electrically charged particle. More charge=larger, stronger field vis versa
Where does a magnetic field occur in relation to an electrified wire?
Around the entire length of the wire
When an electric current runs through a wire, a magnetic field is induced where?
Around the wire
Why is static electricity not useful as a power source?
Because all energy is released at once in static electricity
Why do the geographical poles move?
Because of the polar drift aka iron flow in the molten iron layer.
How does alternating current differ from direct current?
Direct current flows in same direction; direction of alternating current switches back and forth
What are electric field lines?
Drawn just like Magnetic field lines. Field directed away from + charge toward - charge.
What is electricity?
Energy in electric field. Energy= electric energy= electricity. Stored in one place called current electricity, builds up on object called static electricity.
Describe Earth's magnetosphere
Field forms a protective shield. Shield extends 37,000 miles out into space. Protects from solar wind particles
You're going camping, and you need a source of electric current. So, you buy a gasoline-powered:
Generator
How to demagnetize object?
Heat, hammer/pressure, or drop
Where does Earth's magnetic field begin?
In it's iron core
How can you see the field lines?
Iron fillings
What is one possible reason why it's a good idea to conserve electricity?
It is often produced by burning fossil fuels, which are a polluting, non-renewable resource
Which poles attract and repel?
Opposites attract
What can you infer about a source of electricity from an outlet?
Source of alternating current
How would you compare the magnetic field generated by a simple length of wire to the magnetic field generated by a coil of wire?
The coil generates a stronger magnetic field
What did Faraday confirm about electromagnetic induction?
Their needs to be a magnetic field moving for electromagnetic induction to occur
What are sources of mechanical energy?
Wind and fossil fuels
What is a solenoid?
a coil of wire acting as a magnet when carrying electric current.
Name different types of magnets
bar, horse-shoe, ring, cylinder, and disk
Explain lighting
"Heavier, negatively charged particles sink to the bottom of the cloud. When the positive and negative charges grow large enough, a giant spark - lightning - occurs between the two charges within the cloud. ... Most lightning happens inside a cloud, but sometimes it happens between the cloud and the ground." -Planetscience.com
What is current electricity?
"electric current is a flow of electric charge. In electric circuits this charge is often carried by moving electrons in a wire."-wikipedia
What is static electricity?
"imbalance of electric charges within or on the surface of a material. The charge remains until it is able to move away by means of an electric current or electrical discharge"-wikipedia
What is an eddy current?
"loops of electrical current induced within conductors by a changing magnetic field in the conductor"-wikipedia
What is the simplest requirement for an electromagnet?
A length of electrified wire
What do you need to build a working electric motor?
A source of electricity
What is a current?
A steady flow of electricity
What device opens and closes an electric circuit?
A switch
Place the following events in sequence: A) Voltage is increased by a transformer; B) Voltage is decreased by a transformer; C) Electrical current enters your home
A, B, C
What is an electric force?
An invisible force made up of electrically charged particles. Just like magnets opposites attract.
What's a magnet?
An object that produces magnetic forces made of iron, nickel, or cobalt
What makes magnet magnetic?
Atoms are magnetic. When they group and align, it's called magnetic domain. Domain is shown w/ arrows
How does a generator create current?
By using an electromagnet
How are magnets incorporated into credit cards, hard drives, and MRI machines?
Cards- a magnetic strip to remember data Hard drives- same thing as card just it can remove data also MRI- Uses a magnetic image process for a better x-ray
What is the function of every generator on Earth?
Changing mechanical energy into electrical energy
What devices detect the poles?
Compass
What else does Earth's core create?
Core creates the magnetic poles
In physics, to "induce" something is to:
Create it
What is the function of a power source in a circuit?
It provides a steady flow of electrons
What is magnetic field and how are fields affected?
Magnetic field is the magnetic force around a magnet. Affected when it is in another magnetic field
Explain magnetic fields and their lines
Magnetic field travels from the N pole around the magnet to the S pole then back up through to the N pole. Field lines help one visualize what the magnetic field looks like when drawing using arrows, lines, and never cross
How does one make an object a magnet?
Move a magnet over object to align object's domain
What are electrons?
Negatively charged subatomic particles
Three different types of magnets
Permanent- permanently magnetized object, Temporary- Becomes magnet through magnetization Electromagnet- Temporary magnet made by an electric current
What is an Aurora?
Result of solar winds. Particles bump into gas particles at the poles after hitting magnetosphere.
To change the polarity of an electromagnet, you would:
Reverse the current's direction
How would you reverse the direction of the current flowing through the coil in Faraday's experiment?
Reverse the magnet's direction
How does rubber differ from most metals?
Rubber is a good insulator; most metals are good conductors
What determines magnet strength?
Size of magnet and material
What is magnetic break?
Slowing down a magnet with other fields.
What is the main function of a turbine?
Spinning
Which word best describes electricity as it occurs in nature?
Sudden
What might happen if transformers didn't exist?
The electricity in your house might have an extremely high voltage
What happens if you disconnect a circuit from its positive terminal?
The electrons stop flowing, and the current stops
Two electromagnets contain the same types of magnets and wires. But the magnet in the first moves much faster than the second. Therefore:
The first electromagnet has a more powerful current than the second
What is the relationship between electricity and magnetism?
They are two forms of the same basic force
How do electromagnets differ from regular magnets?
They can be turned on and off, their polarity can be reversed, and their strength can be changed
Why are paperclips attracted to magnets?
They contain iron
How does electricity travel from power plants to your house?
Through transmission wires
How might an electric motor be used in a washing machine?
To make the machine spin
What might happen if wires weren't insulated?
We'd be in danger of harm from electric shocks
When will a circuit breaker trip, or turn off?
When a very strong current passes through it
