This is an example of a common experiment used to investigate Hooke’s Law. It should help you understand how to work scientifically.
Aim of the experiment
To investigate how adding mass to a spring affects its extension.
Set up the apparatus as in the diagram
Add a 10 g mass to the holder and record the spring length.
Add another 10 g mass and record the new spring length.
Take away the previous spring length from the new length to calculate the extension (the difference).
Repeat by adding 10 g masses until 100 g is reached.
The independent variable is the mass.
The dependent variable is the extension.
Controlled variables include using the spring and masses used.
Care must be taken with masses.
5 mm (25 - 20 = 5)
What the results mean
The spring extended 5 mm each time a 10 g mass is added (which increased the force due to gravity by 0.1 N). This follows Hooke’s Law which states that the extension of an elastic object (like a spring) is directly proportional to the force added.
Your measurements are accurate if they are close to their true value.
Your measurements are precise if they are similar when completed again.
Your experiment is repeatable if you get precise measurements when it is repeated.
Your experiment is reproducible if others get precise measurements when they repeat it.