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.

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

Improving Accuracy

Calculate the weight added by measuring its mass using an electronic balance on a flat, level surface 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

Add a fiduciary marker with a fine point to the bottom of the coil spring to give precise readings of the length of the coil spring. This makes it easier to see the length of the coil spring by reducing the random error caused by not being exactly at eye level for each repeated result.