Question

part 4- a) discrepancies (12 pts) & b) units (13 pts):
a) discrepancies (12 pts): choose 2 of the labs listed below. for each one of the 2 labs that you choose, give one discrepancy assuming the procedure is followed properly. for each discrepancy you list (6 pts total for each discrepancy), you must state what caused the discrepancy (2pts), how it was mismeasured (2pts), and why it affects the results (2pts). the following answers are not acceptable sources of discrepancy: human error, measurement error, calculation error, rounding error, etc. any answer that suggests procedural error will also not be counted as correct. remember: be specific to the lab.
lab 2 - free fall lab, lab 3 - acceleration, lab 9 - density lab, lab 13 - period and frequency

Explanation:

To solve part a), we'll choose two labs (e.g., Lab 9 - Density Lab and Lab 2 - Free Fall Lab) and analyze discrepancies for each:

Lab 9 - Density Lab:

• Discrepancy Cause: Temperature change affecting the substance's volume (liquids expand/contract with temp).
• Mismeasurement: The graduated cylinder used to measure volume isn’t temperature - controlled, so the liquid’s volume (e.g., water) changes unnoticed.
• Effect on Results: Density is $

ho=\frac{m}{V} $. If volume $ V $ changes (e.g., increases with higher temp), calculated density will be lower than the true value (since $ V $ is in the denominator).

Lab 2 - Free Fall Lab:

• Discrepancy Cause: Air resistance acting on the falling object (e.g., a ball).
• Mismeasurement: The photogate timer measures the time of fall, but air resistance causes the object to accelerate less than $ g $ (9.8 m/s²).
• Effect on Results: The calculated acceleration (from $ d = v_0t+\frac{1}{2}at^2 $, with $ v_0 = 0 $, so $ a=\frac{2d}{t^2} $) will be less than $ g $, as air resistance opposes motion and reduces the net acceleration.

Answer:

Lab 9 - Density Lab Discrepancy:

• Cause: Temperature - induced volume change of the liquid.
• Mismeasurement: Volume measured with a non - temperature - controlled graduated cylinder.
• Effect: Calculated density is inaccurate (lower for expanded liquids).

Lab 2 - Free Fall Lab Discrepancy:

• Cause: Air resistance on the falling object.
• Mismeasurement: Time of fall measured by a photogate, but air resistance alters acceleration.
• Effect: Calculated acceleration is less than the true free - fall acceleration ($ g $).