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Electric Current
Direct Current ●
Direct Current is generated by a chemical reaction in a “cell”. These cells are what are inside batteries.
Direct Current ●
Direct Current is also produced by solar panels. Silicon inside the panels reacts with the sunlight to produce a flow of electrons.
Direct Current ●
Because the chemical reactions are constantly occurring, the flow of electric current is only in one direction.
Alternating Current ●
Alternating Current is generated by reversing, or alternating flow of positive and negative charges.
The direction changes 120 times per second!
Alternating Current ●
Our homes and other buildings use alternating current because it is much more practical for transferring electric energy.
Current The measure of current is called Amperes, or “Amps”. This is the amount of current. Example: Think of runners on a track. The amount of runners would be like the total amount of current.
Voltage ●
Voltage is a measure of the speed of an electric charge. It is measured in Volts (V). Example: This would be like how fast the runners on the track are moving. 9 volts
1.5 volts
120 volts!
Resistance ●
Resistance is also called “electrical friction”. It resists the flow of electrons. Example: Think of resistance like hurdles on the track that the runners have to jump over. It slows them down.
Resistance The thickness of the wire (or other conductor) and the length of the wire affect resistance. ●
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Thinner and longer wires have more resistance. Shorter and thicker wires have less resistance. Measured in Ohms, using the Greek letter, omega: Ω
Calculations ●
Amps = Voltage Resistance Amps = 6 V 2 Ω Amps = 6 V 2 Ω
Calculations ●
Amps = Voltage Resistance 20 A = 120 V Ω Ω x 20 A = 120 V Ω=6
Calculations ●
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Just like when we studies work and power that humans or machines can do, electric energy can produce power too. Remember, power is the rate at which work is done, and is measured in watts. Power (Watts) = Voltage (V) x Current (A)
Calculations ●
Power = Voltage x Current P = 120 V x 15 A P = 1,800 Watts (W)
Power Ratings ●
Power ratings are listed on all electric devices to tell you how much power is needed to operate it. For example:
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A hair dryer needs 1000 watts
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A Clothes dryer needs 4,000 watts
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A typical radio only needs 100 watts
Electrical Energy ●
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Everything that uses power contributes to the overall electrical energy used by a household or other business. The power companies keep track of this in order to send us a bill. Electrical Energy = Power (Watts) x Time (Hours)
Electrical Energy Example: Electrical Energy = 1,550 W x 420 hours Electrical Energy = 651,000 watt-hours Electrical Energy = 651 kilowatt-hours or “kWh”
Circuits ●
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Circuits is a complete, closed path through which electric charges travel. Circuits include an energy source (AC or DC), a load (a device that uses the electricity), and wires to connect everything together (conductive material.) A circuit usually includes a switch, which when open turns the circuit off, and when closed connects the circuit again.
Load ●
A load is a device that converts electrical energy into another form of energy.
Electric energy to light energy
Electric energy to thermal energy
Electric energy to sound energy
Types of Circuits ●
Series Circuit All parts are connected in a single loop and only follows one path. Each load shares the current, so only gets a fraction of the current. All the loads must be turned on and working, or none of them will work.
Types of Circuits ●
Parallel Circuit Includes separate branches so the charges travel more than one path. Each load gets the full voltage so different types of loads can be used (light, hair dryer, TV etc.) One load can be turned off and others will still work.
Magnetism ●
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Anything that attracts iron or materials containing iron is called a magnet. The regions of atoms inside a magnet are all lined up in the same direction, called domains.
Magnetism ●
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All magnets have two ends where the magnet is the strongest. These are called poles. Opposite poles attract. Like poles repel.
Magnetism ●
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The force of attraction or repulsion between magnets is called the magnetic force. The region around the magnet where magnetic forces act is called the magnetic field.
Magnetism ●
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The domains in a magnet can get out of alignment by being dropped or struck very hard. This can demagnetize the object. Permanent Magnets: very difficult to magnetize but stay magnetized for longer periods. Temporary Magnets: Very easy to magnetize but lose their magnetism quickly.
Magnetism from Electricity ●
A solenoid is a coil of wire that produces a magnetic field when an electric current runs through it.
1) The electric current provides a flow of electrons to the solenoid. 2) The flow of electrons gives the solenoid a magnetic field. 3) This magnetic field is attracted to the magnet underneath, Making the coil spin.
Magnetism from Electricity ●
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An electromagnet is a solenoid wrapped around an iron core. When an electric current passes through it, it produces a very strong magnetic field.
Electricity from Magnetism ●
Electricity can be produced from magnetism using a generator. The coil cuts through the magnetic The rotating coil spins between the 2 magnets, producing a current.
A crank spins the coil.
field. Every half turn the flow of electrons goes in the opposite direction. This is Alternating Current.
Direct Current ●
Direct Current is generated by a chemical reaction in a “cell”. These cells are what are inside batteries.
Direct Current ●
Direct Current is also produced by solar panels. Silicon inside the panels reacts with the sunlight to produce a flow of electrons.
Direct Current ●
Because the chemical reactions are constantly occurring, the flow of electric current is only in one direction.
Alternating Current ●
Alternating Current is generated by reversing, or alternating flow of positive and negative charges.
The direction changes 120 times per second!
Alternating Current ●
Our homes and other buildings use alternating current because it is much more practical for transferring electric energy.
Current The measure of current is called Amperes, or “Amps”. This is the amount of current. Example: Think of runners on a track. The amount of runners would be like the total amount of current.
Voltage ●
Voltage is a measure of the speed of an electric charge. It is measured in Volts (V). Example: This would be like how fast the runners on the track are moving. 9 volts
1.5 volts
120 volts!
Resistance ●
Resistance is also called “electrical friction”. It resists the flow of electrons. Example: Think of resistance like hurdles on the track that the runners have to jump over. It slows them down.
Resistance The thickness of the wire (or other conductor) and the length of the wire affect resistance. ●
● ●
Thinner and longer wires have more resistance. Shorter and thicker wires have less resistance. Measured in Ohms, using the Greek letter, omega: Ω
Calculations ●
Amps = Voltage Resistance Amps = 6 V 2 Ω Amps = 6 V 2 Ω
Calculations ●
Amps = Voltage Resistance 20 A = 120 V Ω Ω x 20 A = 120 V Ω=6
Calculations ●
●
Just like when we studies work and power that humans or machines can do, electric energy can produce power too. Remember, power is the rate at which work is done, and is measured in watts. Power (Watts) = Voltage (V) x Current (A)
Calculations ●
Power = Voltage x Current P = 120 V x 15 A P = 1,800 Watts (W)
Power Ratings ●
Power ratings are listed on all electric devices to tell you how much power is needed to operate it. For example:
●
A hair dryer needs 1000 watts
●
A Clothes dryer needs 4,000 watts
●
A typical radio only needs 100 watts
Electrical Energy ●
●
●
Everything that uses power contributes to the overall electrical energy used by a household or other business. The power companies keep track of this in order to send us a bill. Electrical Energy = Power (Watts) x Time (Hours)
Electrical Energy Example: Electrical Energy = 1,550 W x 420 hours Electrical Energy = 651,000 watt-hours Electrical Energy = 651 kilowatt-hours or “kWh”
Circuits ●
●
●
Circuits is a complete, closed path through which electric charges travel. Circuits include an energy source (AC or DC), a load (a device that uses the electricity), and wires to connect everything together (conductive material.) A circuit usually includes a switch, which when open turns the circuit off, and when closed connects the circuit again.
Load ●
A load is a device that converts electrical energy into another form of energy.
Electric energy to light energy
Electric energy to thermal energy
Electric energy to sound energy
Types of Circuits ●
Series Circuit All parts are connected in a single loop and only follows one path. Each load shares the current, so only gets a fraction of the current. All the loads must be turned on and working, or none of them will work.
Types of Circuits ●
Parallel Circuit Includes separate branches so the charges travel more than one path. Each load gets the full voltage so different types of loads can be used (light, hair dryer, TV etc.) One load can be turned off and others will still work.
Magnetism ●
●
Anything that attracts iron or materials containing iron is called a magnet. The regions of atoms inside a magnet are all lined up in the same direction, called domains.
Magnetism ●
●
●
All magnets have two ends where the magnet is the strongest. These are called poles. Opposite poles attract. Like poles repel.
Magnetism ●
●
The force of attraction or repulsion between magnets is called the magnetic force. The region around the magnet where magnetic forces act is called the magnetic field.
Magnetism ●
●
The domains in a magnet can get out of alignment by being dropped or struck very hard. This can demagnetize the object. Permanent Magnets: very difficult to magnetize but stay magnetized for longer periods. Temporary Magnets: Very easy to magnetize but lose their magnetism quickly.
Magnetism from Electricity ●
A solenoid is a coil of wire that produces a magnetic field when an electric current runs through it.
1) The electric current provides a flow of electrons to the solenoid. 2) The flow of electrons gives the solenoid a magnetic field. 3) This magnetic field is attracted to the magnet underneath, Making the coil spin.
Magnetism from Electricity ●
●
An electromagnet is a solenoid wrapped around an iron core. When an electric current passes through it, it produces a very strong magnetic field.
Electricity from Magnetism ●
Electricity can be produced from magnetism using a generator. The coil cuts through the magnetic The rotating coil spins between the 2 magnets, producing a current.
A crank spins the coil.
field. Every half turn the flow of electrons goes in the opposite direction. This is Alternating Current.
