Physics 121 Tutorials and Labs

Fall 2008

Instructor:  Dr. Ayush Gupta (ayush@umd.edu)

Tutorial Instructions and Schedule (PDF)

Lab Guide and Schedule (PDF)

Attendance Policy

Answers to some frequently asked questions on laboratory attendance

There will be no tutorials or labs during Thanksgiving week.

Some tutorials/labs might be different than those in your manuals. In that case, you would be provided with a copy of the appropriate tutorial/lab for that week.

Tutorial Homework:

• Homework is posted on this site, in the column titled "Tut. HW" in the table below (Dr. Redish also posts this HW on his course website).
• Homework is collected each week at the beginning of the tutorial.(**Sections 401 and 402 can turn in the tutorial HW at the start of lab)
• You are not allowed to work on the HW during the tutorial hour.
• The due dates for each tutorial HW are posted in the "Tut. HW Due Data" column below.
• Some weeks there might be special section-specific instructions - these are posted in the "Special Instructions" column.
• Grading: For each HW, any 5 sub-parts are chosen and graded for a total of 5 points. Tutorial HW contributes to your final course grade - but the exact percentage contribution might vary depend on your lecture-instructor.

Frequently Asked Questions

What are the details of the make-up activity?

I am on a waitlist for Phys121. Can I attend the labs/tutorials with some section? I am already attending the lectures.

I have to miss lab on account of religious holidays. What can I do about this?

I missed lab (not a religious holiday). What should I do?

I missed a tutorial due to medical/other reason. What should I do?

My schedule does not allow me to attend the lab at the time that my section meets. Can I attend lab with another section?

I missed the first lab day (week or 09/08-09/12) (whatever reason). What do I do?

I got less than what I expected on my first lab. I usually get better lab grades in other courses. What can I do to improve my grade?

What am I expected to do in the tutorial?

Q:   What are the details of the makeup activity?
A:  

1. The makeup activity will be an assignment of questions based on the laboratories.
2. Click here to Download the Makeup Activity
3. Please make sure with your TA that your name is on the list for the make-up activity.
4. The assignment would be due the week of 12/08-12/13. Hand it to your TA at the beginning of the tutorial hour (the survey week). No late submissions would be accepted.
5. This assignment would make up for only one missed lab and only if you had a valid excuse for that absence. If you have more than one valid absences, you need to talk to Ayush (ayush@umd.edu) or to your lecture professor.
6. Participation grade will be based on your average participation grade over the semester.
   
   

   Q:   I am on a waitlist for Phys121. Can I attend the labs/tutorials with some section? I am already attending the lectures.
   A:   Unfortunately, right now all sections are filled up and logistic limitations just do not allow us to have more than 24 students in any section. Sorry.
   However, I will make an exception for this week (09/08-09/12) - since this is the 2nd week of classes and there may be someone in your section who will drop the the class. In other words, ONLY FOR THIS WEEK (09/08-09/12), you can attend the lab and discussion with some section that you can attend. However, Sept 15 is the last day for schedule adjustments, and so if you are not on the roster by the 15th (i.e. next Monday), then I will not be able to allow you to attend the Lab/Tutorial sessions.
   
   Q:   I have to miss lab on account of religious holidays. What can I do about this?
   A:   We understand that you might have a religious holiday on one of the lab days and cannot really attend that lab. Please submit a written statement at the very next tutorial session (week of 09/15-09/19) stating the date you will be missing and name of the religious holiday. In addition, contact Ayush Gupta (ayush@umd.edu) and let him know about this. Note that missing lab for travel before and after a religious holiday are not considered valid excuses.
   
   If you have to miss one lab day:

   it is your responsibility to
   i) make sure that talk to your group mates and to your TA so you can follow up on what happened the week that you missed,
   ii) make sure that you see Ayush Gupta (ayush@umd.edu) to arrange for a make-up activity at the end of the semester. This would be essential for a complete grade, and,
   iii) make sure that your TA includes the grade from make-up activity in your final lab grade for the semester.

   If you have to miss more than one lab day:

   The best solution would be to find another person who is willing to switch lab-section with you for the whole semester.
   Another solution would be to switch sections with another student for those particular weeks (make sure to switch for two weeks if one of the weeks is part of a two week lab).
   Please try to arrange any changes/switches by next week. You would be responsible for making sure your TA knows of all changes and that your final lab grade takes all these changes into account.
   If none of this is possible, arrange to meet with Ayush Gupta (ayush@umd.edu)

   Q:   I missed lab (not a religious holiday). What should I do?
   A:   If you have a valid reason for missing the lab, such as a medical emergency, bring in a written statement (to you TA) explaining your absence and supporting paperwork (such as a doctor's slip), if any. We will arrange for a makeup activity in the last week of classes - make sure that you email ayush@umd.edu to ensure that you are on the list of students for the make-up activity. Please note: the make-up activity can only cover for one missed lab (and that only if you have a valid excuse).
   Also, refer to the Attendance Policy that is posted online [click here], and also the Lab Guide[PDF] and Tutorial Instructions[PDF].
   
   Q:   I missed tutorial for medical/other reason. What should I do?
   A:   You can attend the tutorial with another section only for that week. Please make arrangements as soon as possible to hand in any homework that you were supposed to turn in to your TA (It is your responsibility to see that your TA gets your homework). Tutorial HW must be handed in within the week that it is due!
     Note that this policy does not apply to laboratory absence.
   
   Q:   My schedule does not allow me to attend the lab at the time that my section meets. Can I attend lab with another section?
   A:   Right now, all sections are filled up and we do not really allow for more than 24 students in each lab section. In general, you should not have registered for a section that meets at a time you cannot attend.
   The only working solution would be to find a student (in one of the sections that you can attend) who is willing to switch labs with you for the whole semester.
   Since the first experiment starts next week, I think it would be best if this switch could be done by the end of this week - that would ensure the least confusion for the other student, the TA, as well as you.
   Here are two ways to find that student who might be willing to switch with you:
   PlanA: This week (i.e. 09/08-09/12), you can show up at the lab/discussion for the section that you would like to switch to, and see if some student can switch with you, starting next week.
   PlanB: If you cannot find a switch-student: I would suggest that you talk to your instructor so that he can give you 5 minutes at the end of the next lecture (is that on Thursday) so you can make a pitch for a replacement student when the whole class is there (increases the probability that you will find a student to switch with you).
   NOTE: This week there is no experiment during the lab; the lab period is used to fill out a conceptual survey. So only for this week, you can attend lab with any of the evening labs - because the survey is an individual activity. By next week, the only solution would be to find a student to switch with.
   Please take care to see that your TA, and the TA for the other student know of this switch. It would be your responsibility to ensure that both TAs know about this, so that the lab grades can be submitted correctly to your lecture-instructor at the end of the semester.
   It would be best if you can also switch the discussion session with that particular student (causes the least confusion). But if that is not possible, you can keep your original discussion session. Once again, it would be your responsibility to make sure that both TAs know of all the changes, so they can deal with the Tutorial HW appropriately.
   
   Q:   I missed the first lab day (week or 09/08-09/12) (whatever reason). What do I do?
   A:   The first day was a survey day - students filled out a diagnostic conceptual survey. This does not impact your lab grade in any way.
   There might be bonus points linked to participating in the survey. Dr. Redish (redish@umd.edu) is the person to talk to about this. Dr. Redish is also the person to talk to if you want to take the survey at another time.
   The regular labs start the week of 09/15 and thereafter the lab attendance policies are in effect. Refer to the Attendance Policy . If you have questions, check out the other FAQs. If you still have questions email ayush@umd.edu
   
   Q:   I got less than what I expected on my first lab. I usually get better lab grades in other courses. What can I do to improve my grade?
   A:   The laboratory-portion this course is probably seeming very unusal and contrary to what you have seen in other courses - and doing what you did in a 'regular' lab might not be the best way to experience or perform well in this lab. In this portion I will try to address some of the anxiety related to the lab experience, and specifically address the issue of what you can do to improve your lab performance and make it more meaningful for yourself.
   

   We have tried to explain some of this in the lab guide [available here]. Please do read that. Note that not all the information in the lab guide is in your manual. So it is essential that you read the guide as soon as you can, preferably before the next lab.
   Having said that, communication is a tricky job, and maybe we could not communicate our message as effectively as we would have liked to think we did in the guide or in the manual. So I will try and take another shot at it. What follows is not a "mantra" to memorize/repeat! Try to make sense of it. Also these are general guidelines. There might be specific instructions/interpretations each week - look to your TA for that.
   
   In many laboratory courses the idea is for you to carry out various experiments that either illustrate what you are learning in lecture or give you some hands on experience with the concepts being taught to you. The philosophy of these labs differs from that: While we do expect that some of the ideas that you are learning in the lecture would help you with the labs, the main purpose of the lab is to give you a taste of what scientific experimentation really is like - designing your own experiment, grappling with issues of measurement, reliability and interpretation of results, presenting and defending your conclusions in a way that would make sense to your "scientific community" and being able to articulate verbally and in writing the 'how' and 'why' of what you are doing.
   
   In more concrete terms, whenever you are in the lab, pay attention to

   • what is the purpose the exercise that you are engaged in
   • why are you doing what you are doing: justifications for any procedure you use or conclusion you come to and
   • examining critically how you possibly could have done better.
   
   None of what I will say below should be taken as an algorithmic procedure to enable you to collect more 'points' in the report. But taking them into consideration should improve the quality of your lab experience and in turn, the quality of your lab report, which would reflect on your lab grade. Grading lab reports is one way of communicating to you our expectations of what we think a good report should pay attention to (remember that these are general points and the interpretation of the extent to which they are fulfilled will always be subjective to some extent):
   
   1. Usually doing an experiment involves decisions on or designing many sub-components of it (for example, if you are measuring the length of a pendulum, you would have decided on particular lenghts, on particular starting points for the swing, particular method to measure a period). Scientists also consider important questions such as - What could someone have done differently? Did you consider some of those ideas, but decided to not use them? Why did you reject those ideas? What impact could these decision have on your measurements? And later, thinking about what impact did your design have on the uncertainty of values measured and on the conclusion.
   2. Is it clear from your report the purpose of what you are doing, and how exactly you are doing it. Would someone else be able to read off your data and understand what each quantity was? Will they know what manipulations of the raw measurements you were doing and why you were doing those particular manipulations. These are some of the important aspects of scientific experimentation
   3. One of the most important points is to be able to articulate what precisely is your data showing you as conclusions, and make a persuasive case for how you got to you conclusion - your actions and calculations: so for example, say you decide that the period of the pendulum does depend on the mass and state that. That is hardly an argument! It is a statement. You should also tell us how you came to that conclusion - for example, you could say that your data showed that the mean period (average over 5 trials) increases from 1.2seconds to 1.5 seconds as you increased the mass from 30 grams to 60 grams in 5 gram increments and that the mean period increased a little bit with each increase in mass indicating that the period of the pendulum depends on the mass of the pendulum-bob. That is better - it tells me that you were looking at the trends in average period of the pendulum to base your conclusion. But it still leaves uncertain why you think this is a good method with respect to the particular question you are trying to answer in your conclusion? why did you consider the average period to base your conclusion about dependency of period on mass? is that the best way to reach the conclusion? Are there other aspects of your data that you could have paid attention to? Were there other groups that paid attention to other aspects of their data? How does your data analysis specifically support the conclusion that you reach? Was the amount of data that you took enough? If you changed by a little bit the criterion you used for deciding on dependency, would your conclusion change? etc. There is not a specific algorithm for this, nor is this an exhaustive list of questions - these questions are to give you a taste of the possible things to think about.
   4. It is also an important aspect of scientific experimentation to critically examine your own exerimental technique & analysis methods as well as those of others. We are always searching of ways to be able to have greater confidence in our conclusions, make them more reliable and persuasive. Would our conclusions change if we took more measurements - if so can we make a reasonable argument of how specifically we could expect them to change? Would taking more data be better or detrimental? What specifically are the shortcomings of the experimental technique (even if we cannot resolve them in this lab) and more importantly, how do these shortcomings specifically affect the quality of the data (do they cause the measurement to be more uncertain & how? do they provide a larger range of values? etc.)? What specifically are the shortcomings of the analysis method and how do they affect/constrain the conclusion that you draw from your experiment+analysis?
   5. At times, it might be better to address deeply one/two issues that is most relevant to your experiment rather than tackle all questions in a shallow manner. The labs are designed to focus your attention on one or two aspects of experimentation each week - and these are mentioned in the 'major goals' box. Pay attention to those and feel free to ask your TA for clarification. But also, if you have already discussed a point in a previous week, we would expect you to remember that aspect of experimentation in successive weeks.
   6. Try to avoid jargon trying to sound "physics-y". Write the report as if the reader is someone with a similar background as you and your classmates. Clearly explain, in common sense terms, any term or procedure that you use. But neither this point, nor others, should be treated as an excuse to write irrelevancies to make your report "look" big. The lab-assessment is also a way to sharpen your judgement of what counts as relevant and what does not in a scientific report
   7. If you have an intuitive idea/notion, explore that and try to articulate your intuition in terms of the concrete data that you have!
   8. In some labs you might not reach a definitive conclusion for the specific objective that you set out to achieve. That is okay, but let us know why you think that your data does not support a definite conclusions. Could you have anything different in procedure or analysis to be able to change this situation; make sure to examine the possible impact to of such suggested improvement - why do you think that the specific change you are suggesting will lead to a better conclusion? This would require you to critically examine the possible shortcomings in your current procedure and analysis and the impact that they had on your data and conclusion. There will be some labs in which you might have to consult the data and/or conclusions of other groups' work to be able to use your own data productively
   9. Continuing on the previous point - not being able to reach a definitive conclusion - remember that the purpose of the lab is to give you a taste of scientific experimentation, not to just apply/illustrate the things you learn in lecture. To that end, participating in the design of experiment, data analysis, and critical examination of your own (and others') experimental procedure, data analysis, & indefinite conclusion are often the experience that we want to provide you in this lab - not necessarily leaving with an "answer" that would be supported by a textbook. To remain authentic to this ideal is perhaps one of the most challenging things for you and for us.
   10. As you can see may of these points are pretty general. If you are not sure of what is being expected of you in a particular section of the experiment or report do ask your TA about that. Maybe, by asking, you are actually helping many other students who might be having a similar difficulty but are shy to ask.
   11. So in the lab report, some of the things to pay attention to are: the specifics of your design, reasons behind particular design decisions, specifics of data collection, clear and understandable recording of data, productive ways to represent the data, specifics of data analysis, clearly stating conclusions, arguments to support your conclusion on the basis of analysis, critical evaluation of procedure and critical evaluation of analysis and conclusion. Of course, on particular weeks there might be specific questions posed by your TA; or raised in class discussion which would become relevant to discuss in the lab report. But in general, just stating what you did or what conclusion you got is hardly enough for a good grade. We are looking for arguments, justifications, reasonings and critical reflection - articulated to make sense.
   12. Grading lab reports is and will remain to quite some extent a subjective endeavor. There might be variations between groups, and will definitely be variations between different sections. The grades for the course are normalized within sections and also between sections, to take into account relative performance, and relative grading styles.
       
       Q:   What am I expected to do in the tutorial?
       A:   The idea for the tutorials is to provide a space for students to come together and engage with conceptual physics topics in small groups. As such, your groupmates can help you much more than the TA in getting value out of the tutorial experience. So don't just concentrate on filling out the worksheet - engage in sensemaking of the physical situations, think about the underlying reasons to an answer, and challenge your own and your groupmates' reasoning with counter arguments or alternate reasonings.
       
       Many students think learning physics means taking in information — facts and formulas and problem solving methods — and committing it all to memory. But, for Einstein and others, learning physics means refining your everyday thinking. And that means, first, becoming aware of your everyday thinking. They may not always think of what they're doing this way, but students who succeed in physics know this instinctively: Learning physics is as much learning about yourself, about how and what you know and see and think, as it is finding out new things about the physical world. This is going to be our primary focus in tutorials, learning how to learn physics.
       
       This course concerns mainly the physics of motion with bits and pieces of other topics. That's something you already know an awful lot about, and what you already know will be the raw material from which you'll build your understanding in the tutorials. Much of it already works perfectly; we'll only need to make it precise, write it down, and follow its implications. And much of it works well in some circumstances but not in others. Sometimes what you "know" in one context just contradicts what you "know" in another, and when that happens you need do some adjusting to reconcile the inconsistency.