Required Practical 18: Force and Extension

About this practical...

There is an obvious link between the force acting on a spring and the amount that is extends. Here, you get to measure it, plot your results, see if you have passed the limit of proportionality (elastic limit) and calculate the spring constant as well as how much energy is in the elastic potential energy store at each point.


1. Collect the equipment to set up the apparatus below

2. Note how far the bottom of the spring reaches onto the ruler by the side and record this as 0 kg added

3. Add the first mass (this is the actual hook part of the masses) and record the mass (g) and the new height for the bottom of the spring

4. Add a mass to the mass hanger and record the new total mass and the new height.

5. Continue until you have added all the masses as instructed by your teacher, do not overload the spring.

Construct a table showing: mass added (g), force applied (N), length (m), extension (m).

Finally plot a graph to show Extension (X-axis) against Force (Y - Axis)

Safety & Managing Risks

Usual lab rules must be followed: Goggles worn throughout the lesson, bags and stools tucked away and notify the teacher of any breakages immediately. Take care with the masses, do not stand under in case masses fall on your toes. Do not overload the springs, if they stretch too far and break, the broken wires may injure people, especially in their eyes. For more detailed information, please consult CLEAPSS.

Technician notes:


Slotted masses (depending on the springs, 10 g intervals and 100 g intervals)

This page was updated on: 8th January 2022