Year 6 Science: Components and what they do
Part of the Year 6 Science components, switches and circuit symbols chapter. Chapter overview · whole chapter on one page
Components and what they do
A component is a part of a circuit. The most common components are:
- the cell, which gives the voltage;
- the bulb, which lights up when current flows through it;
- the buzzer, which makes a sound when current flows through it;
- the switch, which turns the circuit on or off.
A component works differently depending on the voltage and on the rest of the loop. A higher voltage makes a bulb brighter and a buzzer louder.
The table gives the parts of a simple circuit.
| Component | What it does |
|---|---|
| cell | provides the voltage and the energy; it has a positive and a negative end |
| bulb | lights up when current flows through it |
| buzzer | makes a sound when current flows through it |
| switch | opens or closes the loop, turning the circuit off or on |
Key ideas
- A component is a part of a circuit, such as a cell, bulb, buzzer or switch.
- A bulb lights up when current flows through it.
- A buzzer makes a sound when current flows through it.
- A higher voltage makes a bulb brighter and a buzzer louder.
Method. Read the description.
- Read the description. The cell gives the voltage and the energy to the circuit.gives the voltage
- Write the word. So the component is the cell.cell
- Write the answer. cell
Check. The bulb and buzzer use the energy from the cell. ✓
Method. Read the description.
- Read the description. A bulb lights up when current flows through it.lights up
- Write the word. So the component is the bulb.bulb
- Write the answer. bulb
Check. A buzzer makes a sound instead. ✓
Method. Use the rule about voltage.
- Think about the voltage. Three cells give a higher voltage than two cells.4.5 volts is more than 3.0 volts
- Decide. So the buzzer with 3 cells is louder.3
- Write the answer. 3 cells
Check. The rating for 3 cells is 5 out of 5 in Chapter 9. ✓
Watch out
Watch out: a component depends on the rest of the circuit. A bulb in a different circuit may be brighter or dimmer, because the voltage and loop are different.
Exam tip
Exam tip. Name the component, then say what it does when current flows through it.
Try it (with your teacher, or a grown-up at home). With a teacher, build a loop with one cell, one bulb and one buzzer, joined in a row. Watch which component changes. Then add a second cell. Which component changes most? Write your answer in a sentence.
Exercise 10A Components and what they do
Method. Read the table.
- Read the table. A buzzer makes a sound when current flows through it.makes a sound
- Write the word. So the component is the buzzer.buzzer
- Write the answer. buzzer
Check. A bulb lights instead. ✓
Method. Read the table.
- Read the table. A bulb lights up when current flows through it.lights up
- Write the word. So the component is the bulb.bulb
- Write the answer. bulb
Check. A bulb is brighter with a higher voltage. ✓
Method. Read the description.
- Read the description. A switch turns the circuit on or off.on or off
- Write the word. So the component is the switch.switch
- Write the answer. switch
Check. A switch opens or closes the loop. ✓
Method. Read the table.
- Read the table. The cell gives the voltage.voltage
- Write the word. So the component is the cell.cell
- Write the answer. cell
Check. The cell is the source of the energy. ✓
Method. Read the rule.
- Read the rule. A higher voltage makes a bulb brighter.brighter
- Decide. So the answer is yes.yes
- Write the answer. yes
Check. More cells give a higher voltage. ✓
Method. Read the rule.
- Read the rule. A higher voltage makes a buzzer louder.louder
- Decide. So the answer is yes.yes
- Write the answer. yes
Check. Chapter 9 showed this with ratings. ✓
Method. Read the ratings.
- Read the ratings. Two cells give a higher rating, 4, than one cell, 2.4 and 2
- Write the number. So the higher voltage is with two cells.2
- Write the answer. 2
Check. Two cells give 3.0 volts, more than 1.5 volts. ✓
Method. Think about how a circuit is turned off.
- Think about the choice. A switch opens or closes the loop without removing a wire.opens or closes
- Write the word. So the answer is switch.switch
- Write the answer. switch
Check. The switch is the easy way to turn a circuit off. ✓
Method. Check the idea.
- Check the idea. Current must flow round the loop for both a bulb and a buzzer to work.round the loop
- Decide. So Ali is right, and the answer is yes.yes
- Write the answer. yes
Check. A gap stops current in every component. ✓
Method. Read the table.
- Read the table. A buzzer makes a sound, and a bulb gives out light.sound
- Decide. So Priya has confused the two components, and the answer is no.no
- Write the answer. no
Check. Bulbs give light; buzzers make sound. ✓
Method. Think about the voltage.
- Think about the voltage. Three cells give a higher voltage than one cell.higher voltage
- Think about the current. A higher voltage makes more current flow, so the bulb is brighter.more current
- Write the answer. Accept any sentence that says three cells give a higher voltage, so more current flows and the bulb is brighter.
Check. The voltage is the cause of the change. ✓
Method. Think about the circuit.
- Think about the voltage. The voltage across the bulb may be lower in another circuit.lower voltage
- Think about the current. Less current then flows, so the bulb is dimmer.less current
- Write the answer. Accept any sentence that says the voltage or the rest of the loop is different, so less current flows through the bulb.
Check. Components depend on the whole circuit. ✓
Method. Think about the circuit.
- Think about the component. The component is the same, but the circuit around it is different.circuit around it
- Think about the behaviour. So the voltage and the loop change how it behaves.behaves
- Write the answer. Accept any sentence that says the component is the same, but the voltage and the rest of the loop are different, so it behaves differently.
Check. A component works within its circuit. ✓