Lesson 6 Part 1
When you rub a plastic ruler on your head, your hair sticks to the ruler. This happens because of static electricity.
The plastic ruler has equal numbers of positive and negative charges before it is rubbed. These charges balance each other. It is said to be electrically neutral.
However, rubbing it upsets this balance. When the ruler is rubbed against your hair, negative charges travel from the hair to the ruler. The ruler now has more negative charges than positive charges. It has become negatively charged. Because the negative charges have left the hair, it now has more positive charges than negative charges. It has become positively charged. Such an imbalance of electric charges is called static electricity.
The plastic ruler has equal numbers of positive and negative charges before it is rubbed. These charges balance each other. It is said to be electrically neutral.
However, rubbing it upsets this balance. When the ruler is rubbed against your hair, negative charges travel from the hair to the ruler. The ruler now has more negative charges than positive charges. It has become negatively charged. Because the negative charges have left the hair, it now has more positive charges than negative charges. It has become positively charged. Such an imbalance of electric charges is called static electricity.
Lesson 6 Part 1-1
When you rub a plastic ruler on your head, your hair sticks to the ruler.
Lesson 6 Part 1-2
This happens because of static electricity.
Lesson 6 Part 1-3
The plastic ruler has equal numbers of positive and negative charges before it is rubbed.
Lesson 6 Part 1-4
These charges balance each other.
Lesson 6 Part 1-5
It is said to be electrically neutral.
Lesson 6 Part 1-6
However, rubbing it upsets this balance.
Lesson 6 Part 1-7
When the ruler is rubbed against your hair, negative charges travel from the hair to the ruler.
Lesson 6 Part 1-8
The ruler now has more negative charges than positive charges.
Lesson 6 Part 1-9
It has become negatively charged.
Lesson 6 Part 1-10
Because the negative charges have left the hair, it now has more positive charges than negative charges.
Lesson 6 Part 1-11
It has become positively charged.
Lesson 6 Part 1-12
Such an imbalance of electric charges is called static electricity.
Lesson 6 Part 2
You can make an electrical circuit with a battery, a light bulb and two wires. The battery provides an electric current through the wires and the bulb. The bulb lights up as the current flows through it.
To measure the size of the current, you put an ammeter into the circuit. Current is measured in amperes (A) or amps for short.
The battery’s chemical energy is used to push a current around the circuit. The “push” that the battery gives to the current is called voltage. It is measured in volts (V) on a voltmeter.
The more voltage the battery supplies, the more current flows in the circuit. If you want to make the light bulb brighter, connect more batteries in series.
To measure the size of the current, you put an ammeter into the circuit. Current is measured in amperes (A) or amps for short.
The battery’s chemical energy is used to push a current around the circuit. The “push” that the battery gives to the current is called voltage. It is measured in volts (V) on a voltmeter.
The more voltage the battery supplies, the more current flows in the circuit. If you want to make the light bulb brighter, connect more batteries in series.
Lesson 6 Part 2-1
You can make an electrical circuit with a battery, a light bulb and two wires.
Lesson 6 Part 2-2
The battery provides an electric current through the wires and the bulb.
Lesson 6 Part 2-3
The bulb lights up as the current flows through it.
Lesson 6 Part 2-4
To measure the size of the current, you put an ammeter into the circuit.
Lesson 6 Part 2-5
Current is measured in amperes (A) or amps for short.
Lesson 6 Part 2-6
The battery’s chemical energy is used to push a current around the circuit.
Lesson 6 Part 2-7
The “push” that the battery gives to the current is called voltage.
Lesson 6 Part 2-8
It is measured in volts (V) on a voltmeter.
Lesson 6 Part 2-9
The more voltage the battery supplies, the more current flows in the circuit.
Lesson 6 Part 2-10
If you want to make the light bulb brighter, connect more batteries in series.
Lesson 6 Part 3
Copper wires are generally used to connect electrical circuits. A substance that allows electricity to flow through it, such as copper, is called a conductor.
Electrical wires and plugs are usually covered with plastic or rubber for safety. A substance that does not allow electricity to flow through it is called an insulator.
You can use any kind of metal wire to connect an electrical circuit. The amount of the electric current that can flow through the circuit depends on the metal you use.
Every material has electrical resistance. The greater the material’s resistance is, the less the current flows through it. Good conductors, which have very low resistances, such as copper and aluminum, allow large currents to flow through them. On the contrary, very small currents can flow through insulators because they have very high resistances.
Electrical wires and plugs are usually covered with plastic or rubber for safety. A substance that does not allow electricity to flow through it is called an insulator.
You can use any kind of metal wire to connect an electrical circuit. The amount of the electric current that can flow through the circuit depends on the metal you use.
Every material has electrical resistance. The greater the material’s resistance is, the less the current flows through it. Good conductors, which have very low resistances, such as copper and aluminum, allow large currents to flow through them. On the contrary, very small currents can flow through insulators because they have very high resistances.
Lesson 6 Part 3-1
Copper wires are generally used to connect electrical circuits.
Lesson 6 Part 3-2
A substance that allows electricity to flow through it, such as copper, is called a conductor.
Lesson 6 Part 3-3
Electrical wires and plugs are usually covered with plastic or rubber for safety.
Lesson 6 Part 3-4
A substance that does not allow electricity to flow through it is called an insulator.
Lesson 6 Part 3-5
You can use any kind of metal wire to connect an electrical circuit.
Lesson 6 Part 3-6
The amount of the electric current that can flow through the circuit depends on the metal you use.
Lesson 6 Part 3-7
Every material has electrical resistance.
Lesson 6 Part 3-8
The greater the material’s resistance is, the less the current flows through it.
Lesson 6 Part 3-9
Good conductors, which have very low resistances, such as copper and aluminum, allow large currents to flow through them.
Lesson 6 Part 3-10
On the contrary, very small currents can flow through insulators because they have very high resistances.
Lesson 6 Part 4
When we observe an electrical circuit, three major units are used. One is volts (V) to measure voltage between two points of the circuit. Another is amperes (A) to show how much current is flowing through the circuit. And the last is ohms (Ω), which represent the resistance of the resistor.
In an electrical circuit, the current passing through a resistor between two points is proportional to the potential difference between the two points, and inversely proportional to the electrical resistance between the two points. This relation can be shown in the formula: I = V/R. In this formula, I, V, and R represent the current in amperes, the potential difference in volts, and the resistance in ohms, respectively.
This is called Ohm’s law.
In an electrical circuit, the current passing through a resistor between two points is proportional to the potential difference between the two points, and inversely proportional to the electrical resistance between the two points. This relation can be shown in the formula: I = V/R. In this formula, I, V, and R represent the current in amperes, the potential difference in volts, and the resistance in ohms, respectively.
This is called Ohm’s law.
Lesson 6 Part 4-1
When we observe an electrical circuit, three major units are used.
Lesson 6 Part 4-2
One is volts (V) to measure voltage between two points of the circuit.
Lesson 6 Part 4-3
Another is amperes (A) to show how much current is flowing through the circuit.
Lesson 6 Part 4-4
And the last is ohms (Ω), which represent the resistance of the resistor.
Lesson 6 Part 4-5
In an electrical circuit, the current passing through a resistor between two points is proportional to the potential difference between the two points.
Lesson 6 Part 4-6
And inversely proportional to the electrical resistance between the two points.
Lesson 6 Part 4-7
This relation can be shown in the formula: I = V/R.
Lesson 6 Part 4-8
In this formula, I, V, and R represent the current in amperes, the potential difference in volts, and the resistance in ohms, respectively.
Lesson 6 Part 4-9
This is called Ohm’s law.