GCSE Physics Required Practical: Investigating Hooke's Law

Key Stage 4

Meaning

Investigate the relationship between the extension of a spring and the force applied to that spring.

Experiment

Variables

Independent Variable: The force applied to the spring.

Dependent Variable: The extension of the spring.

Control Variables: The spring being used.

Method

	A diagram of the apparatus used to investigate the effect of a force on the extension of a spring.

Set up the equipment as shown in the diagram.

Measure the original length of the spring using a ruler.
Attach a known weight (approximately 1N) to the spring.
Measure the new length of the spring.
Calculate the extension of the spring by subtracting the original length from the new length of the spring.
Repeat steps 2-4 up to around 6N.
Plot a graph with the force of weight on the y-axis and the extension on the x-axis. The gradient of this graph will be the spring constant of the coil spring.

Improving Accuracy

Calculate the weight added by measuring its mass each time and using the equation \(W=mg\) with \(g=9.8\). This will give a more accurate knowledge of the weight rather than relying on the number printed on the weights.

Add a fiduciary marker to the bottom of the coil spring to prevent any error caused by not reading the ruler from eye level.

Ensure the spring is not moving when taking measurements of it's length.

	A fiduciary marker can be added to improve accuracy and precision of the length measurements.

Improving Precision

Calculate the weight correct to two significant figures by measuring its mass to two significant figures each time and using the equation \(W=mg\) with \(g=9.8\). This will give a more precise knowledge of the weight rather than relying on the number printed on the weights which may be precise to only one significant figure.

Add a fiduciary marker with a fine point to the bottom of the coil spring to give a precise reading of the length of the coil spring.