Compare conductors and insulators, series and parallel circuits, switches, fuses and circuit symbols. Review suitability for your learners before teaching.
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Worksheet StudioPractice pack · Ages 7-9
Conductors, insulators & circuits
Take your time. Show your thinking.
1. Why are electrical wires made with a copper metal core on the inside and a flexible plastic coating on the outside: copper conducts the electricity while the plastic insulator prevents electric shocks and short circuits, or plastic conducts electricity?
Cell (+) ── Switch ── (−) · Closed Series Loop
2. What happens if two identical cells in a torch are put in facing opposite directions (+ touching +): their voltages cancel out and the bulb will not light, or the bulb shines twice as bright?
Cell (+) ── Switch ── (−) · Closed Series Loop
3. What circuit component allows current to flow in ONE direction only (and emits light when it is an LED): a diode (or light-emitting diode) or a fixed resistor?
Cell (+) ── Switch ── (−) · Closed Series Loop
4. In a parallel circuit, how does the total current leaving the battery compare to the currents in the individual parallel branches: the total current equals the sum of the currents in the branches, or the total current is zero?
Cell (+) ── Switch ── (−) · Closed Series Loop
5. In a series circuit, how does the electric current measured at different points around the single loop compare: the current is the SAME at every point in a series loop, or it gets used up by the bulb?
Cell (+) ── Switch ── (−) · Closed Series Loop
6. What component has a resistance that decreases when brighter light shines on it (used in automatic street lights): a light-dependent resistor (LDR) or a thermistor?
Cell (+) ── Switch ── (−) · Closed Series Loop
7. In a standard circuit diagram, what does a long thin vertical line paired with a shorter, thicker vertical line represent: a single electrical cell, or an open switch?
Cell (+) ── Switch ── (−) · Closed Series Loop
8. If you add a second cell in series (pointing in the same direction, + to −) to a circuit with a single bulb, what happens to the bulb: it shines more brightly because the voltage pushing the current has doubled, or it goes out?
Cell (+) ── Switch ── (−) · Closed Series Loop
9. What happens when you open (turn off) a switch in a simple series circuit: it creates a gap (open circuit) that stops the current flowing and turns the bulb off, or it makes the bulb brighter?
Cell (+) ── Switch ── (−) · Closed Series Loop
10. Why are the lights and sockets in a home wired in PARALLEL rather than in series: each light is on its own branch so it receives full voltage and can be switched on or off independently without turning off the others, or parallel uses no wire?
Cell (+) ── Switch ── (−) · Closed Series Loop
11. In a simple SERIES circuit with two bulbs in a single loop, if one bulb’s filament breaks (blows), what happens to the other bulb: it goes out too because the single circuit loop is broken, or it stays lit?
Cell (+) ── Switch ── (−) · Closed Series Loop
12. What component has a resistance that changes significantly with temperature (used in digital thermometers and thermostats): a thermistor or a loudspeaker?
Cell (+) ── Switch ── (−) · Closed Series Loop
12 questions · Seed 56 · Age guidance, not curriculum certification
View the answer key
Worksheet StudioAnswer key · Ages 7-9
Conductors, insulators & circuits
Answers and reasoning. Review before teaching.
1. Why are electrical wires made with a copper metal core on the inside and a flexible plastic coating on the outside: copper conducts the electricity while the plastic insulator prevents electric shocks and short circuits, or plastic conducts electricity?
Copper conducts the electricity while the plastic insulator prevents electric shocks and short circuits
The metal core carries current; the outer plastic sheath keeps users safe.
2. What happens if two identical cells in a torch are put in facing opposite directions (+ touching +): their voltages cancel out and the bulb will not light, or the bulb shines twice as bright?
Their voltages cancel out and the bulb will not light
Cells in series must be aligned positive-to-negative so their voltages add together.
3. What circuit component allows current to flow in ONE direction only (and emits light when it is an LED): a diode (or light-emitting diode) or a fixed resistor?
Diode (or light-emitting diode)
A diode has low resistance in the forward direction and very high resistance in reverse.
4. In a parallel circuit, how does the total current leaving the battery compare to the currents in the individual parallel branches: the total current equals the sum of the currents in the branches, or the total current is zero?
The total current equals the sum of the currents in the branches
By Kirchhoff’s current law (conservation of charge), current splits at a junction and recombines on return.
5. In a series circuit, how does the electric current measured at different points around the single loop compare: the current is the SAME at every point in a series loop, or it gets used up by the bulb?
The current is the SAME at every point in a series loop
Charge is conserved—the same number of coulombs per second passes every point in a single loop; energy is transferred, not current used up.
6. What component has a resistance that decreases when brighter light shines on it (used in automatic street lights): a light-dependent resistor (LDR) or a thermistor?
Light-dependent resistor (LDR)
In bright light an LDR’s resistance falls; in darkness its resistance rises.
7. In a standard circuit diagram, what does a long thin vertical line paired with a shorter, thicker vertical line represent: a single electrical cell, or an open switch?
Single electrical cell
The long line marks the positive (+) terminal and the short thick line marks the negative (−) terminal of a cell.
8. If you add a second cell in series (pointing in the same direction, + to −) to a circuit with a single bulb, what happens to the bulb: it shines more brightly because the voltage pushing the current has doubled, or it goes out?
It shines more brightly because the voltage pushing the current has doubled
Two 1.5 V cells connected correctly in series supply 3.0 V, increasing the current through the bulb.
9. What happens when you open (turn off) a switch in a simple series circuit: it creates a gap (open circuit) that stops the current flowing and turns the bulb off, or it makes the bulb brighter?
It creates a gap (open circuit) that stops the current flowing and turns the bulb off
A switch controls a circuit by safely opening or closing the conducting gap.
10. Why are the lights and sockets in a home wired in PARALLEL rather than in series: each light is on its own branch so it receives full voltage and can be switched on or off independently without turning off the others, or parallel uses no wire?
Each light is on its own branch so it receives full voltage and can be switched on or off independently without turning off the others
In a parallel circuit, if one lamp fails or is switched off, current still flows through the other branches.
11. In a simple SERIES circuit with two bulbs in a single loop, if one bulb’s filament breaks (blows), what happens to the other bulb: it goes out too because the single circuit loop is broken, or it stays lit?
It goes out too because the single circuit loop is broken
A break anywhere in a series loop stops current throughout the entire loop.
12. What component has a resistance that changes significantly with temperature (used in digital thermometers and thermostats): a thermistor or a loudspeaker?
Thermistor
A thermistor is a temperature-sensitive resistor.
12 questions · Seed 56 · Age guidance, not curriculum certification
Worksheet StudioPractice pack · Ages 7-9
Conductors, insulators & circuits
Take your time. Show your thinking.
1. Why are electrical wires made with a copper metal core on the inside and a flexible plastic coating on the outside: copper conducts the electricity while the plastic insulator prevents electric shocks and short circuits, or plastic conducts electricity?
Cell (+) ── Switch ── (−) · Closed Series Loop
2. What happens if two identical cells in a torch are put in facing opposite directions (+ touching +): their voltages cancel out and the bulb will not light, or the bulb shines twice as bright?
Cell (+) ── Switch ── (−) · Closed Series Loop
3. What circuit component allows current to flow in ONE direction only (and emits light when it is an LED): a diode (or light-emitting diode) or a fixed resistor?
Cell (+) ── Switch ── (−) · Closed Series Loop
4. In a parallel circuit, how does the total current leaving the battery compare to the currents in the individual parallel branches: the total current equals the sum of the currents in the branches, or the total current is zero?
Cell (+) ── Switch ── (−) · Closed Series Loop
5. In a series circuit, how does the electric current measured at different points around the single loop compare: the current is the SAME at every point in a series loop, or it gets used up by the bulb?
Cell (+) ── Switch ── (−) · Closed Series Loop
6. What component has a resistance that decreases when brighter light shines on it (used in automatic street lights): a light-dependent resistor (LDR) or a thermistor?
Cell (+) ── Switch ── (−) · Closed Series Loop
7. In a standard circuit diagram, what does a long thin vertical line paired with a shorter, thicker vertical line represent: a single electrical cell, or an open switch?
Cell (+) ── Switch ── (−) · Closed Series Loop
8. If you add a second cell in series (pointing in the same direction, + to −) to a circuit with a single bulb, what happens to the bulb: it shines more brightly because the voltage pushing the current has doubled, or it goes out?
Cell (+) ── Switch ── (−) · Closed Series Loop
9. What happens when you open (turn off) a switch in a simple series circuit: it creates a gap (open circuit) that stops the current flowing and turns the bulb off, or it makes the bulb brighter?
Cell (+) ── Switch ── (−) · Closed Series Loop
10. Why are the lights and sockets in a home wired in PARALLEL rather than in series: each light is on its own branch so it receives full voltage and can be switched on or off independently without turning off the others, or parallel uses no wire?
Cell (+) ── Switch ── (−) · Closed Series Loop
11. In a simple SERIES circuit with two bulbs in a single loop, if one bulb’s filament breaks (blows), what happens to the other bulb: it goes out too because the single circuit loop is broken, or it stays lit?
Cell (+) ── Switch ── (−) · Closed Series Loop
12. What component has a resistance that changes significantly with temperature (used in digital thermometers and thermostats): a thermistor or a loudspeaker?
Cell (+) ── Switch ── (−) · Closed Series Loop
12 questions · Seed 56 · Age guidance, not curriculum certification
Worksheet StudioAnswer key · Ages 7-9
Conductors, insulators & circuits
Answers and reasoning. Review before teaching.
1. Why are electrical wires made with a copper metal core on the inside and a flexible plastic coating on the outside: copper conducts the electricity while the plastic insulator prevents electric shocks and short circuits, or plastic conducts electricity?
Copper conducts the electricity while the plastic insulator prevents electric shocks and short circuits
The metal core carries current; the outer plastic sheath keeps users safe.
2. What happens if two identical cells in a torch are put in facing opposite directions (+ touching +): their voltages cancel out and the bulb will not light, or the bulb shines twice as bright?
Their voltages cancel out and the bulb will not light
Cells in series must be aligned positive-to-negative so their voltages add together.
3. What circuit component allows current to flow in ONE direction only (and emits light when it is an LED): a diode (or light-emitting diode) or a fixed resistor?
Diode (or light-emitting diode)
A diode has low resistance in the forward direction and very high resistance in reverse.
4. In a parallel circuit, how does the total current leaving the battery compare to the currents in the individual parallel branches: the total current equals the sum of the currents in the branches, or the total current is zero?
The total current equals the sum of the currents in the branches
By Kirchhoff’s current law (conservation of charge), current splits at a junction and recombines on return.
5. In a series circuit, how does the electric current measured at different points around the single loop compare: the current is the SAME at every point in a series loop, or it gets used up by the bulb?
The current is the SAME at every point in a series loop
Charge is conserved—the same number of coulombs per second passes every point in a single loop; energy is transferred, not current used up.
6. What component has a resistance that decreases when brighter light shines on it (used in automatic street lights): a light-dependent resistor (LDR) or a thermistor?
Light-dependent resistor (LDR)
In bright light an LDR’s resistance falls; in darkness its resistance rises.
7. In a standard circuit diagram, what does a long thin vertical line paired with a shorter, thicker vertical line represent: a single electrical cell, or an open switch?
Single electrical cell
The long line marks the positive (+) terminal and the short thick line marks the negative (−) terminal of a cell.
8. If you add a second cell in series (pointing in the same direction, + to −) to a circuit with a single bulb, what happens to the bulb: it shines more brightly because the voltage pushing the current has doubled, or it goes out?
It shines more brightly because the voltage pushing the current has doubled
Two 1.5 V cells connected correctly in series supply 3.0 V, increasing the current through the bulb.
9. What happens when you open (turn off) a switch in a simple series circuit: it creates a gap (open circuit) that stops the current flowing and turns the bulb off, or it makes the bulb brighter?
It creates a gap (open circuit) that stops the current flowing and turns the bulb off
A switch controls a circuit by safely opening or closing the conducting gap.
10. Why are the lights and sockets in a home wired in PARALLEL rather than in series: each light is on its own branch so it receives full voltage and can be switched on or off independently without turning off the others, or parallel uses no wire?
Each light is on its own branch so it receives full voltage and can be switched on or off independently without turning off the others
In a parallel circuit, if one lamp fails or is switched off, current still flows through the other branches.
11. In a simple SERIES circuit with two bulbs in a single loop, if one bulb’s filament breaks (blows), what happens to the other bulb: it goes out too because the single circuit loop is broken, or it stays lit?
It goes out too because the single circuit loop is broken
A break anywhere in a series loop stops current throughout the entire loop.
12. What component has a resistance that changes significantly with temperature (used in digital thermometers and thermostats): a thermistor or a loudspeaker?
Thermistor
A thermistor is a temperature-sensitive resistor.
12 questions · Seed 56 · Age guidance, not curriculum certification