P4 Science Heat Expansion Cable Wires Question – Full Explanation

Introduction

Why do cable wires hang loosely during a hot day?
This common real-life scenario appears frequently in exams and is a classic P4 Science heat expansion cable wires question.

In this guide, we explain the concept clearly using the teacher’s exact board explanation, so students can answer confidently.

The Question

The diagram shows cable wires hanging loosely under the sun.

Students are asked:

Which of the following statements about the cable wires is correct?

Options include:

1. The cable wires lost heat to the sun and expanded
2. The cable wires lost heat to the sun and contracted
3. The cable wires gained heat from the sun and expanded
4. The cable wires gained heat from the sun and contracted

Step-by-Step Explanation (Teacher’s Working)

Step 1: Identify the Source of Heat

• The sun is a heat source
• The cable wires are exposed to sunlight

👉 Therefore, the cable wires gain heat from the sun

Step 2: What Happens When Materials Gain Heat?

In P4 Science, students must remember:

• Materials expand when heated
• Materials contract when cooled

Since the wires gain heat, they will expand

Step 3: Link Expansion to the Diagram

• Expanded wires become longer
• Longer wires appear looser and sag more

This explains why the wires are hanging loosely

Step 4: Choose the Correct Option

Correct statement:

✅ The cable wires gained heat from the sun and expanded

👉 Correct Answer: Option (3)

Key Concepts

Common Mistakes Students Make

❌ Thinking the wires lost heat
❌ Mixing up expansion and contraction
❌ Ignoring the role of the sun as a heat source

For Parents

This P4 Science heat expansion cable wires topic helps children:

• connect science concepts to real life
• build observation and reasoning skills
• prepare for higher-level application questions in exams

Conclusion

To answer P4 Science heat expansion cable wires questions correctly:

• Identify the heat source
• Determine if heat is gained or lost
• Apply expansion or contraction accurately

That’s why Option (3) is the only correct answer.