Static Electricity
Electric Circuits
Using Electrical Energy
Potpourri
100
What is an electrical charge and what kinds of electrical charges are there?
An electrical charge is a property of matter that whether something has a positive or negative charge. There are positive and negative charges.
100
What is an electric current and a circuit?
An electric current is a flow of electric charges. The path along which electric current flows is called a circuit.
100
How is electrical energy used?
Electric currents carry the energy that people use. Electrical devices change this energy into other kinds of energy such as heat, light, and motion.
100
What does a fuse do if the electrical current in a circuit is too high? What is a circuit breaker and surge protector?
The fuse will melt and cause an open circuit. A circuit breaker stops the flow of charges by switching off the current if it gets too high. Surge protectors break the circuit if too much electric current flow through it.
200
What do charges that are different (e.g., positive and a negative charge) do to each other?
They attract each other.
200
What is a simple circuit?
It has three basic parts; a power source (e.g., battery), a load to power (e.g., a bulb), and connectors to carry the electrical charges.
200
What are transformers used for?
They are used to change the voltage of electrical current as it travels to and from the power plant. A step-up transformer increases the voltage and a step-down transformer decreases the voltage.
200
What is a complete, unbroken circuit called? What is an open, broken circuit is called?
A closed circuit (electric current can flow) An open circuit (electric current cannot flow)
300
What do charges that are alike (e.g., two positive charges) do to each other?
They repel each other.
300
What affects electric currents?
Voltage and resistance affect electric currents. Voltage is , measured in units called volts and is the strength of the power source. Resistance is the ability of a substance to oppose or slow down electric current (conductors have very little resistance and insulators have a large amount of resistance).
300
Give an example of how electrical energy is converted into heat.
Some furnaces use electrical energy to heat homes. Some stoves use electrical energy to heat food. Inside a hair dryer, electric current flows through wires which heat the air inside the dryer.
300
Give two examples of good insulators.
Wood, glass, rubber, and plastic do not allow electrical changes to pass through them easily so they are good insulators.
400
What is static electricity?
It is the buildup of electrical charges on an object. A buildup means that it has more of one kind of charge than the other (e.g., more negative than positive).
400
What is a series circuit?
All the electrical charges flow in the same direction along a single path. The parts of a series circuit are connected in one loop. The current moves from one power source through wires to one load and then through another load. Finally, the current flows back through a wire to the power source.
400
Give an example of how electrical energy is converted into light.
In an incandescent light bulb as the filament resists the electrical current it heats up and glows. A florescent light uses a gas to produce light. Electric current makes the gas glow.
400
Give two examples of good conductors.
Copper and silver allow electrical charges to flow through them easily so they are good conductors.
500
What is an electrical discharge? How is lightning an electrical discharge?
Electrical discharge is the movement of static electricity from one object to another. Lightning is the discharge of static electricity inside a cloud. Lightning can occur between a cloud and the ground, two clouds, or between two oppositely charged parts of the same cloud. Negative charges build up at the bottom of the cloud. Positive charges build up on the ground. These two charges attract each other. As negative charges move through the air, they make a spark we see as lightning.
500
What is a parallel circuit?
A parallel circuit is a circuit in which the electric current flows through more than one path. These different paths are called branches. The branches divide the electric current between them. If any branch of the parallel circuit is removed or broken, the current will still flow through the other branches.
500
Give an example of how electrical energy is converted into motion.
Electric motors change electrical energy into motion (electrical devices that move). Electric motors can be found in toys, washing machines, fans, drills, and many other devices.
500
Draw a series circuit. Draw a parallel circuit.
See page 300 in your online science book for a picture of a series circuit. See page 302 in your online science book for a picture of a series circuit.
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