Year 9 Science · Unit 3 · Lesson 17
Foundation Worksheet
Learning Goals
Match each component to its symbol and job
Write the letter of the matching description in the middle column. Each letter is used once.
| Component | Letter | Symbol and job |
|---|---|---|
| Cell | A. A gap in a line with a hinged link: opens or closes the circuit | |
| Lamp (bulb) | B. A circle with a V inside: measures the voltage across a component, and is connected in parallel | |
| Switch | C. A circle with an A inside: measures the current, and is connected in series | |
| Resistor | D. A long line and a short line side by side: provides the voltage that pushes charge around the circuit | |
| Voltmeter | E. A small empty rectangle (older diagrams use a zigzag): opposes the current and limits it | |
| Ammeter | F. A circle with a cross inside: changes electrical energy into light and heat |
1. Define voltage and current in your own words, and give the unit of each.
Sort it: what job does each part do?
Write each part in the correct box. Each box gets two parts.
Source
Load
Conductor
Control
Fill the gap
Choose the correct word from the word bank. Each word is used once. Two words will not be used.
A torch contains a battery, a bulb and metal strips that form a closed . The battery provides the , the electrical push that moves charge around the loop. The metal strips make a good because they have a very low and let electrons flow easily. The plastic case is an , so charge cannot flow through it into your hand. The rate at which charge flows past a point is called the , and it is measured in the (A).
2. Draw a circuit diagram with two cells, a switch, a lamp and an ammeter in one loop, using the correct symbols. Then describe what happens when the switch is closed.
Investigation: one torch lamp, three packs of cells
Zoe tested a torch lamp with packs of 1, 2 and 3 cells. A voltmeter across the lamp and an ammeter in the loop gave these readings.
| Cells in the battery pack | Voltage across the lamp (V) | Current through the lamp (A) |
|---|---|---|
| 1 | 1.5 | 0.20 |
| 2 | 3.0 | 0.30 |
| 3 | 4.5 | 0.36 |
Source: sample class results.
3. Work out the lamp’s power for each pack of cells, using P = V × I.
1 cell W
2 cells W
3 cells W
4. (a) Which pack gave the lamp the most power, and so the brightest light? (b) Use E = P × t to calculate the energy the lamp changes in 2 minutes with the 2-cell pack. Change the time to seconds first.
(b) Energy J
Scenario: a torch that will not light
Ava switches on her torch, but the bulb stays dark. The torch has two cells, a switch, a bulb and metal strips that connect them.
5. Describe how Ava could find the fault by checking each part of the circuit in turn. For each part, explain how a fault there would stop the bulb lighting. Use the words “complete circuit” and “current”.