Required Practical: Force and Extension

This lesson covers the required practical investigation into the relationship between force and extension for a spring, as required by the AQA GCSE Physics specification (4.5.4). This practical demonstrates Hooke's law and is one of the most frequently tested required practicals in the GCSE Physics exam. You must know the method, equipment, variables, results analysis, and safety precautions in detail.

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Hooke's Law

Hooke's law states that the extension of an elastic object (such as a spring) is directly proportional to the force applied to it, provided the limit of proportionality is not exceeded.

The equation for Hooke's law is:

F = k x e

Where:

• F = force applied (N)
• k = spring constant (N/m)
• e = extension (m)

The spring constant (k) tells you how stiff the spring is. A larger spring constant means the spring is stiffer and harder to stretch.

Spring	Spring Constant (N/m)	Meaning
Soft spring	10	Easy to stretch
Medium spring	50	Moderate stiffness
Stiff spring	200	Hard to stretch