Hooke's Law - GCSE Science Required Practical

Summary

This video script outlines an experiment to demonstrate Hooke's Law, where a spring's extension is measured as different amounts of force are applied. The procedure involves precise measurements of force and extension, converting values from centimeters to meters. Data is recorded for forces of 1N, 2N, 3N, 4N, and 5N, and a graph is plotted to showcase the linear relationship between force and extension. The gradient of the graph gives the spring constant, calculated as 21.2 N/m, confirming the validity of Hooke's Law. The experiment also highlights the importance of careful measurement to avoid systematic errors.

Takeaways

• 😀 Start the experiment by carefully hanging the spring and securing the ruler so that its zero mark aligns with the bottom of the spring for accurate measurements.
• 😀 Ensure that the spring is vertically suspended and free from obstructions to allow accurate extension measurements.
• 😀 When measuring the extension, always use the correct scale on the ruler, as some rulers have two scales (one counting up and one counting down).
• 😀 Record the extension in centimeters and convert to meters by dividing by 100 before entering it into your data table.
• 😀 The weight of each 100g mass corresponds to a force of 1 Newton, so each 100g increment will increase the force by 1N.
• 😀 Carefully stop any oscillation in the spring before recording the extension to avoid measurement errors due to motion.
• 😀 The experiment involves adding 1N increments (from 1N to 5N) to the spring and measuring the extension at each stage.
• 😀 To calculate the spring constant (K), plot the force (in Newtons) on the y-axis and the extension (in meters) on the x-axis.
• 😀 Choose appropriate scales for the graph to maximize the use of the paper and ensure that the plotted points are clearly visible.
• 😀 After plotting the points, draw a line of best fit through the data points to determine the relationship between force and extension.
• 😀 The spring constant (K) is calculated from the gradient of the line of best fit, which represents the force per unit extension.

Q & A

What is the objective of the experiment described in the video?

The objective of the experiment is to investigate Hooke's Law by measuring the extension of a spring under various applied forces and determining the spring constant (k).

What is the significance of using a ruler that starts at zero in the experiment?

Using a ruler that starts at zero ensures that the measurement of the spring's extension is accurate and eliminates any potential error from the starting point of the ruler.

How is the force applied to the spring calculated?

The force applied to the spring is calculated using the equation F = mg, where m is the mass hung on the spring (in kilograms) and g is the acceleration due to gravity, typically taken as 10 m/s² for simplicity.

Why is it important to convert measurements from centimeters to meters?

It is important to convert measurements from centimeters to meters because the final recorded values need to be in standard SI units (meters) to maintain consistency and accuracy in the experiment.

What role does the ruler play in minimizing potential errors during measurement?

The ruler, when clamped in place, ensures that the measurement starts from the zero mark aligned with the bottom of the spring, minimizing errors related to incorrect positioning of the ruler.

What is the expected relationship between force and extension according to Hooke's Law?

According to Hooke's Law, the extension of the spring is directly proportional to the applied force, meaning as the force increases, the extension also increases proportionally.

How do you calculate the spring constant (k) from the graph?

The spring constant (k) is calculated by finding the gradient (slope) of the force-extension graph. This is done by dividing the change in force (ΔF) by the change in extension (Δx), giving the formula k = ΔF / Δx.

What does the intercept above the origin in the graph suggest about the experiment?

The intercept above the origin suggests a potential systematic error in the experiment, possibly due to incorrect measurement of the zero extension point or misalignment of the spring with the ruler.

What could cause the spring not to return to its original position after the masses are removed?

If the spring does not return to its original position, it indicates that the spring was stretched beyond its elastic limit, which means it no longer follows Hooke's Law.

How does the gradient of the force-extension graph relate to the spring constant?

The gradient of the force-extension graph is equal to the spring constant (k). A steeper gradient indicates a stiffer spring, while a shallower gradient indicates a more elastic spring.