Physics 131 Introduction

Instructor: Dr. Michael Chen

Office: P9442

Office Hour: MWF. 10:30-11:30am; or by appointment

Email: mxchen@sfu.ca

Lab Technician: TBA

Section TA Email

D100 Chang Min KIM cmk4@sfu.ca

D200 Shaojie YIN sya9@sfu.ca

Physics 131 Introduction

Week of Laboratory Prelab Assignment/Quizzes

Jan. 7 General Introduction, Error Analysis none

Jan. 14 Lab 1: The Simple Pendulum (8) Error Analysis Assignment (5)

Jan. 21 Lab 2: DC Circuits and Measurements (6)

Prelab Questions (2)

Jan. 28 Lab 3: AC Circuits and the Oscilloscope (6)

Prelab Questions (2)

Feb. 4 Lab 4: The Magnetic Field (8) Prelab Questions (2)

Feb. 11 Reading break – no lab

Feb. 18 Lab 4: The Magnetic Field (again)

Feb. 25 Lab 5: Ray Optics, Reflections, and Concave Mirrors (6)

Prelab Questions (2)

Mar. 4 Lab 6: Refraction and Thin Lenses (8) Prelab Questions (2)

Mar. 11 Lab 7: Polarization and Colour (6) Prelab Questions (2)

Mar. 18 Lab 8: Interference and Diffraction (6) Prelab Questions (2)

Mar. 25 Practice for Practical Exam

Apr. 2, 3 Makeup Week

Apr. 8 Practical Exam (30)

Physics 131 Introduction

Formal Report

• Lab 4: The Magnetic Field (focus on the current balance and your measurement of m0 in particular).

• Engineering students taking ENSC 102 concurrently will have their formal report marked by the ENSC 102 instructor.

• A draft of your report will be due at the start of class, Monday, March 4. (Engineering students taking ENSC102 must hand in the draft to the instructor of ENSC 102 by Friday March 8).Your draft will be marked and feedback provided, which you will use to polish up your report.

• The finalized report is due by Wednesday, April 3. (April 5 for engineering students taking ENSC 102) 

Physics 131 Introduction

Course Policies• All labs must be done in your scheduled section.

• If you miss a lab, you must bring me medical documentation ASAP. There will be a makeup week near the end of the semester.

• Prelab assignments: Due 10 minutes before the lab starts. Late prelab assignments will not be accepted.

• Lab write-ups are due at the end of the lab. All lab write-ups must be done in the lab notebooks.

• Late work will not be accepted.

• Do not copy data or anything else from others – hand in your own work

Physics 131 Introduction

What to do each week

1. Read the lab manual! Check other references, in particular your text!

2. Do the prelab assignment.

3. Think about what you are trying to measure and try to figure out which issues will be important in doing the experiment.

4. Come to lab; listen to a brief lecture about the week’s material.

5. Do the experiment. You will work in pairs with the same lab partner throughout the semester. Make sure you record all data, including uncertainties. Make graphs and calculations as you go to guide your experiments.

6. Use a pen to record data. Do not use a pencil! When you make a mistake, just cross it out (one can still see the bad data). Don’t use white-out to cover it up.

7. After taking data, finish the calculations, error analysis, and write a short conclusion.

8. Turn in work by the end of class, i.e., 5:20 pm, sharp!

Physics 131 Introduction

Grading

Your course grade will be based on prelab assignments, the lab notebook, the formal report and the practical exam. It is required to complete all the labs to receive a passing grade of the course.

• Prelab Assignments: 2 marks each (except for the first assignment which is 5 marks) • Notebooks: 6 marks for each lab, except for Labs 1, 4 and 5, which are 8 marks each

0: No show 1: Do experiment partially with incomplete results 2–3: Do experiment with major error in method or analysis 4–5: Do experiment satisfactorily but with minor faults6: Do experiment well Error analysis: 2 marks (Lab 1, Lab 4 and Lab 6).

• Practical exam: 30 marks• Formal Report: 20 marks • Semester total: 123 marks maximum

Physics 131 Introduction

Drop-a-Ball ExperimentMeasure the time it takes for a ball at rest to drop by 2.00m.

• > 3) Next drop a ball from above your shoulders, and have the students record the time on a stop watch. Have at least 10 of them write their times on the board in a table with column headings: Trial #, Measured Value of t_i (sec), and Deviation d_i = x_i - <x> (sec). Comment on the distribution and discuss the factors that contribute to this. Then have the students calculate the average, the difference between each measurement and the average (i.e. deviation), and the standard deviation. Finish by showing them how to formally combine the average and standard deviation (e.g. t = 3.60 +/- 0.09 s).> > 4) Before leaving tell the students to read Lab 1: The Pendulum and do the Error Analysis Problems before coming to the lab the following week.>

Physics 131 Introduction

Drop-a-Ball ExperimentMeasure the time it takes for a ball at rest to drop by 2.00m.

Trial #

Time ti (sec)

Deviationdi=xi - <x> (sec)

Result: The time it takes for the ball to drop by 2.00 m is

t = 0.67 ± 0.05 sec

Physics 131 Introduction

Statistical Analysis: Suppose we have many measurements, each with random errors.

The mean and the standard deviation describe the distribution of data expected. These should not change as the number of measurements is increased.

Our estimate of the mean will improve, so we expect the standard deviation of the mean to get smaller as we do more measurements.

Mean

Standard Deviation

Uncertainty in Mean

10

5

0

0.90.80.70.60.50.4

10

5

0

0.90.80.70.60.50.4

Time (s)

10

5

0

0.90.80.70.60.50.4

30

300

3000

(a)

(b)

(c)

Physics 131 Introduction

To do before you come to the lab next week

• Read lab 1 (The Pendulum) of the lab manual, and

check the references if necessary.• Do the prelab assignment.