Dr. Wragg's Physics Labs

Guidelines for Lab Reports

General
A lab experience is an integral part of your exploration of the concepts of the physical universe. The laboratory is a hands-on, active environment. Working in teams, you will carry out experiments which will allow you to assess, apply, verify, or discover concepts, principles, and laws. Some investigations will be cook-book in form; i.e., the procedure will be set out clearly. In some activities, you will be the scientist; i.e., you will have to design all of the steps for a procedure which will allow you to answer a question. All experiments require observation, measurement, analysis, drawing conclusions, and presenting your results. These are skills that transcend this class and are of major value in any field you pursue.

Please note that the most common problem with the safety practices indicated in the beginning of the lab manual is that you must wear closed-toe shoes. Not having suitable footwear is sufficient grounds for being removed from lab for that day, resulting in a score of zero.

In cases where my policies or procedures differ from those in the lab manual, mine take precedence. It is common for me to alter the directions printed in the lab manual.

If you have a question, comment, or complaint please let me know. Even an anonymous note under my door is fine. Note that there is an anonymous web-based email page available from my home page and is linked from the top of this page. Don't let my published office hours be an impediment to finding me at any time you have a question. Ordinarily I am pleased to see you any time you can drop in. You can phone or email ahead of time to set up a meeting if you wish. I am usually around. Please leave me a note if you can't find me.

General Structure
We have 3 hours for each lab exercise. During the first lab period you will be assigned to a group. The group will be changed from time to time during the semester. You should exchange contact information with your partners. All members are expected to participate in the lab process. At the conclusion of the lab period all equipment will be restored to its original order. Note that lab is not a race to see who can finish first.

Generally lab reports will be be a collective effort submitted by the entire group. At any time a student may choose to prepare and turn in an individual lab report, independent of their lab partners. Lab reports will be due either at the end of the laboratory period or at the beginning of the next class meeting. I will specify which is the case early in each lab period. Lab reports due by the end of the lab period may be hand written. Those due the following lab period must be done prepared using computer tools for word processing, graphing, etc.

Attendance
Attendance is important. There is opportunity on the lab schedule to make up labs. You must make prior arrangements, at least 48 hours notice is required to get the equipment ready. Only labs in the recent block can be made up. For example, you may only make up the second lab in the first makeup session, not at the end of the semester. Makeup lab reports must be written and turned in by the end of that lab period.

To document an absence for any class

• Go to 67 George Street (white house next to Stern Center) to discuss absences and fill out the appropriate forms.
• If you have questions consult Constance Nelson or Dean Evelyn Nadel in that office.
• Forms are available online and can be faxed to the office at 953-2290, or you can fill them out in the office on George Street.
• You will need documentation for health, personal, or emergency situations.
• It is your responsibility to get me timely information if you are on an athletic team or on a College-sponsored field trip.

Tardiness is rude, especially to your lab partners. It disrupts the flow of the class. Please be polite to your classmates and me by being on time. I will penalize students for tardiness. Since quizzes are given at the beginning of the period, one built-in penalty is the possibility of missing a quiz, or not having much time to do it. Tardiness that negatively impacts your lab partners will result in you being penalized on your grade for that lab.

Lab Report
The standards for the lab reports will go up as the semester progresses, as you are learning how to observe and communicate effectively. Please take heed of my comments in class and on your graded lab reports.

Due Dates
Some lab reports will be due the day of the lab, by the end of the lab period. Others may be due the beginning of the following week's lab period. Late reports may be accepted (at my whim) but are usually penalized by at least 20%. We may also have one or two performance-based labs, in which your result translates directly into a score for that lab.

Quizzes
Quizzes will usually be given at the beginning of lab. They will be about anything you can reasonably be expected to know. This usually means they will be relevant to the previous lab, but they may also require rudimentary knowledge of the current lab. There will be no make ups for missed quizzes. I drop the one lowest quiz score.

Grades
I give you specific feedback aabout your grade with each quiz and lab report. I consider 8/10 on a lab to be "B" work and 6/10 on a lab to be "C" work. I encourage you to see me at any time for my assessment of your work. The grading distribution is as follows:

   Quizzes      15%
   Lab Reports   85%
   Total        100% of course grade

Guidelines for the Lab Report

Ordinarily, reports due the same lab period need not be typed, those due the next week will be typed. In either case please make sure that the names of all people participating in writing the report for your group are on the lab report.

Format of the Report
There is no single template for every experiment. There is more than one way to effectively structure a report. They tend to share common features: what you did, why you did it, what you got, and what it means. A well thought out and well written laboratory report not only serves to condense your experiment into an easily remembered form but also frequently provides additional insight as you deal with questions arising in summarizing your experiences.

All reports will have —

• Title
• Abstract of no more than 100 words (what you did and what you got)
• Description/diagram of the apparatus
• Theory and Procedure (equations connected to the experiment)
• Results (in a reader-friendly format, often as tables or graphs)
• Interpretation of the results

Lab reports commonly have sections such as introduction, procedure, data, results, and discussion. Discussion of the limitations of the experiment, and intrinsic sources of error are almost always appropriate. Note that mistakes on the part of the experimenter are NOT considered intrinsic sources of error.

Most importantly, a good lab report will show to the reader that you clearly see the physical principles involved as well as how this experiment employs that principle. In our laboratory exercises accuracy is slightly secondary to the principles involved. However, a "10" report must show care and accuracy in the measurements and the computations, as well as insight into the experiment.

A good lab report is: neat, clear, well organized, complete, thoughtful, and reflects your understanding of the laboratory. Graphs should be on graph paper or computer generated plots. They should be a suitable size. It is difficult to make a graph too big and easy to make it too small. Generally, a graph worth doing is worth at least a half-page of space. Put the objective and procedure in your own words, but don't make them too extensive. Sketches of the apparatus, with important features and variables labeled and measurements shown are almost always a necessary ingredient in a good lab report. The sketch is particularly useful in connecting variables in equations with physical aspects of the apparatus. Don't abuse significant figures. The aforementioned features are required for a grade of 8 on the report. To get a 10 a lab report has to demonstrate all of the above, and show special insight in the performance and/or interpretation of the lab.

Intro Physics Lab Report Tips

• Communicate: Most of what makes a good physics lab report has very little to do with physics. You are working on general observation and communication skills, and the ability to draw valid conclusions. These skills are valuable in any field. Make it clear and concise.
• Procedure: A very brief narrative. Don't refer to the lab manual.
• Errors: Quantify the errors intrinsic to the procedure and tools. Looking at these errors allows the reader to have a sense of the quality of your results. Have some sense, or explicit statements about how big an effect the uncertainties and errors had on the result. Human error (i.e., a screw-up) is not what goes here. If you make a mistake, then fix it.
• Tables: Data and results can often go in the same table. Put units in the column header.
• Trials: How many trials do you need to do? As in a real job, you have to ask the questions, "how long do I have to do the experiment, how long does a trial take, how much money does each trial cost, how consistent are the results of each trial?"
• Diagrams: Make them simple, schematic figures, not artistic. Usually diagrams show variables that are used in equations. That is, in addition to showing the physical set-up, they connect the physical reality to the mathematical abstractions.
• Results and Discussion: This is where you give your answers, discuss their significance, and compare/contrast to accepted values, and perhaps speculate on how to do it better, within reason.
• Significant Figures: Be sensible here. If you are writing down all the numbers on your calculators display you are likely being absurd
• Avoid subjective evaluation Don't use phrases such as "we learned a lot," or "the results are good," or "this was a hard experiment." Stick to concrete statements such as, "our results are 5% greater than the accepted result."
• Results and Discussion: This is where you give your answers, discuss their significance, and compare/contrast to accepted values, and perhaps speculate on how to do it better, within reason.
• Conclusions: If you have a solid Results and Discussion section you usually would not need a formal Conclusions section. Don't repeat the results, but interpret the significance of them. Did you support something? Did you meet the objective? Did your results agree with your expectations? Avoid subjective evaluations of your results or the experiment. For example, don't say, "Our results are good."
• Length: Make your case concisely. After college you will find yourselves in the situation of having a limited time or space to present your case. Learn to concentrate on the important issues. Sentences tend to be much shorter than in literary writing.
• Overall: Ask yourself if someone who wasn't there would be able to follow your report. Does it have logical flow, and enough information?

Grading
You will receive a grade of from 0 to 10 on each laboratory exercise. I consider 9-10 to be an "A," 7-8 to be a "B," and 5-6 to be a "C." I do not have to give every member of the group the same grade on the report. Your grade will be based primarily on your written laboratory report but may be weighted by other factors, including:

1. My evaluation of your manner of performance and technique.
2. Your contribution to the efforts of the group.
3. Appearance of the lab report.

Safety in the Lab

First and foremost is safety. Always! We will go over the lab safety section of the manual during the first lab meeting. It is mostly common sense for a physics laboratory environment. You have the responsibility and are accountable for following lab rules and maintaining safety in the lab.

Safety in the laboratory and classroom is everyone's concern and is mostly a matter of maturity and attention. Most physics experiments and demonstrations use simple and safe equipment. Don't allow this to lull you into a false sense of security. Instructors may eject students from a day's lab exercise when those students violate the safety rules. This will probably result in grades of zero for the day for the ejected students.

I. General Education Learning Outcomes

1. Students apply physical/natural principles to analyze and solve problems.
2. Students explain how science impacts society.

Learning Objectives

• Learn experimental and data analysis methods to test and verify certain fundamental laws of physics involving vectors, equations of motion, Newton’s laws of motion, energy, simple harmonic motion, waves, and heat through hands-on activities.
• Enhance observational and analytical skills
• Learn about measurement errors and error estimation methods
• Improve the ability to articulate thoughts and ideas
• Broaden an appreciation for logical qualitative and quantitative reasoning.
• Enhance scientific writing skills.
• Enhance teamwork and communication skills.
• Learn lab safety

Learning Outcomes

After the successful completion of this class, the students will be able to:

• Use basic instruments (meter sticks, stopwatches, triple-beam balances, calorimeters, etc.) to make measurements
• Describe the terms "accuracy" and "precision" in measurements
• Design and carry out measurements based on the directions given by the lab instructor and in the experimental manual
• Collect data (manually and/or using computers) and tabulate it with appropriate units and significant figures
• Draw sketches, graphs, etc. and use them to analyze the data
• Estimate uncertainties associated with the measurements
• Discuss results and compare them with accepted values
• Draw conclusions from observations and measurements in an experiment and prepare a lab report following the guidelines given
• Use computer software to collect data and create graphs, report observations, and tabulate results.
• Apply appropriate methods of safely handling equipment and performing laboratory procedures
• Apply the graphical and component methods to add vectors
• Measure the displacement, time, velocity and acceleration of an object in constant velocity and when accelerating. Express the data graphically and make the appropriate analysis.
• Determine the range of a projectile fired at an angle with respect to the horizontal.
• Investigate the relationship between frictional force and the contact area of the surfaces as well as the normal force between the surfaces.
• Investigate conservation laws.
• Calculate the centripetal force, angular velocity, and centripetal acceleration on a mass undergoing uniform circular motion.
• Solve for torque in a rigid body and discuss the concept of the center of mass of an object.
• Calculate the buoyant forces exerted on objects using Archimedes principle and/or Investigate Bernoulli’s principle and the conservation of energy in fluid mechanics.
• Investigate the conservation of energy in simple harmonic motion
• Discuss and measure the angular speed and centripetal force of an object in circular motion.
• Establish a qualitative relationship between the period of oscillation of a simple pendulum and its length, the mass of the bob and the effective acceleration of gravity.
• Observe the existence of standing waves and determine the wavelength of sound in resonant tubes.
• Determine the specific heat of substances.