PHYS 124 L6 Springs II Manual_cf0e74c70afddc1706a633d00297b1b3

Chapter 13 Lab 6: Springs II

13.1 Pre-lab Preparation

• Review the corresponding section of the lab manual before starting.

• Bring a laptop to the laboratory session for data collection and analysis.

13.2 Safety

• Keep feet clear of falling weights attached to the springs.

• Oscillate springs vertically to minimize side-to-side wobbling.

13.3 Purpose

• Aim: Determine unknown mass and spring constant using techniques from the previous lab.

• Focus on:

  • Experimental design

  • Reducing uncertainties

  • Repeatability of measurements

  • Data collection techniques

13.4 Introduction

• Theory follows from the previous lab.

• Equipment provided for measuring oscillation periods includes proper springs and tools.

• Emphasis on the value of prototyping and iterative testing in research.

  • Start with simple methods, improve with better instruments if necessary.

• Goal is to measure the oscillation period to find the unknown mass.

13.5 Procedure

• Form groups of two or three; each group gets:

  • Springs

  • Known masses

  • An unknown mass (identified by ID number)

  • Meter stick

• Utilize previous methods (Hooke’s Law, simple harmonic motion) to determine spring constant.

• Methods to measure oscillation:

  • Using a stopwatch

  • Video analysis with Tracker or LoggerPro

  • Magnetometer on phone to monitor oscillation

• The method chosen will not impact grading, focus on achieving best results.

Strategies for Measurement

• Discuss choices with TA if uncertain.

• Determine optimal number of measurements and whether to average them.

• Consider measuring multiple oscillation periods for better accuracy.

• Address uncertainties in measurements.

13.5.1 Hooke’s Law

• Determine the spring constant with Hooke’s Law, referencing back to the lab manual if needed.

• Real springs have a minimum length when coils press together, which affects measurements.

• Plot G = G - G0 (where G0 is a reference position), slope important for determining values.

13.5.2 Simple Harmonic Motion

• Begin with small amplitudes to prevent spring coils from hitting each other.

• Use linear fits to determine spring constant and mass.

  • Linear relationships:

    1. 1/l^2 = B + C

    2. Use transformations to plot data for analysis.

• Calculate periods of oscillation for various mass configurations; utilize slopes for calculations.

• Full error analyses to be conducted, assume certain errors minimal for simplicity.

13.6 Analysis

• Uncertainties must be addressed through propagation rules for overall uncertainty intervals.

• Measurement agreement classifications:

  • Good Agreement: 0 ≤ G ≤ XG

  • Moderate Agreement: XG < G ≤ 2XG

  • Poor Agreement: 2XG < G ≤ 3XG

  • No Agreement: 3XG < G

13.7 Appendix: Magnetometer

• Use phone magnetometer for oscillation measurement by attaching a magnet to the mass.

• Download Phyphox app for data collection; avoid placing the phone directly under masses.

• Oscillation should occur entirely above or below the phone's plane to avoid data distortion.

• Options for data export: Google Drive, email, etc.

13.8 Assignment

• Submit a PDF with the following:

  1. Description of experimental process and choices made (mass selection, data methods, etc.).

  2. Table of Hooke's Law results with uncertainties.

  3. Graph of Hooke's Law results with linear trendline and detailed caption.

  4. Table of simple harmonic motion results, including raw data and plotted values.

  5. Graph of simple harmonic motion with linear trendline and caption.

  6. Spring constant values comparison from both methods with uncertainties.

  7. Mass values from measurements compared to expected mass from TA.

  8. Discussion on the accuracy of this lab compared to previous ones and strategies to reduce uncertainties.

  9. References and acknowledgements.