Physics 119 Waves & Optics Lab

Frequently Asked Questions about the 1xx Labs

General Information

Make-up Labs



Accounts and payment

Course enrollment

Assignments and course administration

WebAssign questions and question coding

Scoring and grading in WebAssign


General Information ^

How do I get into a lab section that is full?

Please refer to the Overload Instructions located here:

I need to change my section. What do I do?

The instructors for the 1xx series of courses do not handle registration issues. For that we use a professional: Please contact our Program Coordinator Susan Miller,, in the Physics/Astronomy Bldg, Rm. C-136, phone 206-543-4982, for section changes, add codes, overload requests or other registration matters.

Who is my T.A. And what is his/her email address?

Please refer to the Lab Section/T.A. Info section of your course web page:

PHYS 117:
PHYS 118:
PHYS 119:
PHYS 121:
PHYS 122:
PHYS 123:

If you cannot find your TAs email address on the associated TA Info page for your section, you should be able to find it on the Physics Department's website. Look for the appropriate quarter and course number.

When does my section meet and where is my lab room?

Please see your MyUW time schedule to find when and where your section meets. You may also use the following link to the registrar's time schedule:

Summer 2017 Time Schedule, Physics

Here is a link to a map highlighting where to find PHYS 1xx classrooms:

I have lost something in a lab. Who do I talk to about lost and found?

First talk to your T.A. If your T.A. does not have it and has not turned it in somewhere, talk to the T.A. immediately AFTER the section you attended. Next, talk to Jack Olsen ( Finally, talk to the Physics Front Office located in room C-121 of the Physics/Astronomy Building.

What do I need to bring to the lab?

You should bring the following items with you to every class meeting:

Learn to use your scientific calculator, especially how to use logarithms, roots and powers, and most important, the statistical functions of finding the mean and sample standard deviation of a set of numbers.

Do I need protective clothing (lab coat, goggles, etc.) for the labs?

No, you do not need protective clothing for the 1xx physics labs. It is rare for hazardous material or procedures to be used in physics labs, and on those rare occasions when you would need protective wear, it will be provided.

Make-up Labs ^

What do I do if I miss a lab?

If you miss your lab session, please try to attend a different section in the same week. You need to obtain permission from the TA of that section and inform him/her of your regular section. It is your responsibility to let your regular TA know that you attended a different section in order for you to get credit for attending the lab. It is better to complete a lab the same week that it is scheduled rather than in the makeup week because subsequent labs may build on it. Also, the number of labs you may make up during the last week is very limited (no more than 2). And, of course, the last week of classes tends to be very busy with finals preparation.

Please note: You may not regularly attend a lab section (or any UW class) that you are not registered for. If you are unable to attend the section you are registered for on a regular basis, you should request a section change.

What happens with the Post-Lab if I miss a lab session? Will I lose points on it too?

If you miss an In-Class session, you may work on the Post-Lab assignment, however, it is recommended that you wait until you complete the In-Class session. If you make-up the In-Class session during the week that the lab is offered, by attending another session, you can complete the post-lab by the usual due date. If, however, you make-up the lab during the make-up week, the due-date for the Post-Lab will be reset to a new date, as long as it has not already been completed.

I missed the lab session. Can I still do the post-lab?

Yes, but it is not recommended unless you have no alternative. Because the Post-Lab draws on what you do in the In-Class session, some questions may use data or concepts that would be covered during the session.

I attended a different lab section than the one I am registered for. Can I email my TA so that I get credit for the in-class part?

No, you must obtain both the TA's initials whose class you attended and the initials of your regular TA in orer to verify your attendance. Anyone could email their TA claiming that they went to another section.

I have a low or a zero score on a Post-Lab. Can I make the whole lab up, and redo the Post-lab?

I missed a Post-Lab, but I did the In-Class session. Can I make-up just the Post-Lab?

No. There are no make-ups on Post-Labs past the 1 week make-up window. The reason that the Post-Lab due date is reset when you make-up the In-Class session during make-up week is because you really should do the In-Class session before attempting the Post-Lab. If you already did the In-Class session, you had enough information to do a good job on the Post-Lab.

The score for the Post-Lab may be excused if you have a valid reason for missing it, but there are no make-ups on Post-Labs alone (past the usual window).

When is the make-up week? When and where can I sign up for the make-up?

A lab make-up sign-up will be made available during the last weeks of the quarter. It may be a web-based or paper-based sign up, depending on the particular lab instructor's practice. Paper sign-up sheets are usually posted in the lab room if these are being used.

The make-up week itself occurs during the last full week of classes.

How many make-up sessions are there? Will there be a make-up session during my regular time?

The number of make-up sessions depends on the number of people needing to make-up a lab, and thus there will not be as many make-up sessions as there are regular section meetings during the make-up week. Usually there are somewhere between 1/3 to 1/2 of the usual meeting times made available for make-ups. These make-up sessions are run during time periods allotted for the usual sections, so you may have one during your usual time, but this is not guaranteed.

Where are the make-up labs held?

The make-up labs are held in the same group of rooms used for the regular lab meeetings, however, the meeting for a particular experment may not be in the same room that your section met in. You should go to your usual lab room, look for the TA, and ask him or her where your make-up experiment is set-up. The reason for the ambiguity is that we do not know how many of each experiment will be needed until the make-up sessions start.

Grades ^

Who should I contact if I have a missing grade on my transcript (an X instead of a number grade)?

You should contact your T.A. and and the lab professor for that series. The lab professor will then need to complete out a change of grade form and submit it to the Registrar.

If you have aquestion about WebAssign and grading, see Scoring and Grading in WebAssign.

WebAssign ^

I have never used WebAssign before. What should I do first?

First, read the WebAssign Information page on this website. It will tell you how to gain access to WebAssign. To learn more about how to answer questions on WebAssign see the other questions in this FAQ and consult the online WebAssign Student Help

Accounts and payment ^

Does WebAssign cost money? How much?

WebAssign access does cost money for students. The amount depends upon whether the WebAssign course offers access to questions from a published text. WebAssign access may grant the use of an electronic version of the text and use WebAssign versions of the homework questions that are found in that text. When you log in to WebAssign you will be asked to either enter a code that will give you acces to the course for the term, or purchase access by using a credit card.

Note that there is a grace period of 2 weeks following the start of the term where you may work on WebAssign without paying anything. If you are uncertain whether you will continue with the class, you may want to wait a few days before making the charge on your credit card. If you wait until the grace period expires, you can only view the work you have done; you will not be able to do any new work.

How do I pay for Access?

Can I use an access card that I bought at the bookstore?

Can I have my parents billed?

I bought a "lifetime access code". Can I use this for the labs?

For Physics 117, 118, or 119 you must pay for access online with a credit card. These lab-only courses do not use an access code system.

Can I use a debit card instead of a credit card?

Probably, but you need to check with WebAssign directly. The physics department has no control over the method of payment for WebAssign accounts. However, for all other sorts of transactions, a debit card acts the same as a credit card.

Why can't I use the access card from my textbook that I bought at the bookstore?

See the above questions. The UW physics labs doe not use this method, even though you may have bought a text with such a card.

I had a WebAssign account last quarter. Do I need to renew it?

You need to pay for access to each course you are taking each quarter. The account does not carry over from quarter to quarter. If you do not think this is correct, for example, you believe that you paid for a year's worth of access, you must resolve the matter with WebAssign. The UW has no control over user account access or payment.

I am sure that I have paid the fee. Can the professor help me get access to WebAssign?

Sorry, but no. The professor and the program coordinator (and all other people who work for UW) are customers of WebAssign, just like any student. They cannot control student access to WebAssign. You must contact WebAssign directly to resolve account access and payment problems. The contact information is on the WebAssign web site.

My credit card was rejected by WebAssign, and I am past the 2 week grace period. What should I do?

Contact WebAssign directly. They may extend your grace period. The professor or program coordinator cannot give you access. The professor can, however, allow extensions to or grant an excuse from the missed assignments, if he or she deems it appropriate.

Course enrollment ^

How does WebAssign know what course(s) I am taking?

WebAssign and the UW have a cooperative arrangement that works through the system that keeps track of UW NetIDs (your UW email username). This arrangement is made to work with what is called the "Shibboleth authentication system" or through UW's Canvas "Learning Management System" (LMS), depending on the particular class. When the instructor or program coordinator sets up the class on WebAssign, he or she enters code that links your particular class to the UW system. When you register for a course and login to WebAssign, WebAssign communicates with the UW database. At that time, your name is added to the roster of students on WebAssign.

What happens to my work if I change sections?

As of Spring 2016, all sections of a particular physics course use a single WebAssign class. Thus, your WebAssign class stays the same even if you switch sections. For example, if you changed from Physics 117A to Physics 117C, both A and C are linked to the same WebAssign page, and even though your registration changes in the UW system, your WebAssign page does not change.

Please note: If you change courses, you cannot have your work transferred in WebAssign, even if the assignments are the same in both. For example, if you were transfer between physics 121 AM and physics 117 C (two different courses, even though some assignments are the same), then you could not have your work transferred. In these cases, you should request to have your scores only copied over to the assignments in the new section, by using a score override. Contact your professor in order to do this.

What happens to my work if I drop the course? Can I use it if I sign up for another term?

Your work stays on WebAssign. When you drop the course, the only thing that happens on WebAssign is that your name is moved from the "active" student roster to the "dropped" student roster.

You may not use this work for a later re-enrollment in the course. Under special circumstances, the professor may agree to copy your old scores into the new course by using the score override feature, for example, if you are making up an incomplete.

Assignments and course administration ^

Who creates the assignments?

The instructor of the course is responsible for the creation of the assignments. To create an assignment means to (1) pick the questions, (2) determine the points allotted to each question, and (3) set the type of feedback (marks shown, hints, solution, etc.) that students will see, and when (before or after the due date).

How do I find out how many points an assignment or a question in an assignment is worth?

The total points for a whole assignment is shown in various places. For example, you can see this from the assignment link itself and under the grades (after the due date has passed). To see the points allotted to any question or answer you need to view the assignment itself. The points for each question are listed near the top of the assignment window. To see the points for any specific entry in a multi-part question, click on the Show Details link at the top of the question window.

Note that this is one type of feedback that may be blocked by the instructor, so if you are looking at a Post-Lab before the due date (for example), you may not be able to see this information.

How can I tell whether my submission has been recorded?

If you see a red X or a green checkmark, your submission has been recorded. You can also see whether your submission is recorded by noting the number of submissions counter in the information bar at the top of the question. An example is shown in the image at right: this question has recorded 1 out of a possible 5 submissions.

Why can't I see whether I got full points on an assignment?

It is up to the instructor to decide how much feedback to allow students to see. In some cases the score on an assignment may be blocked until after the due date has passed. This may be to prevent unscrupulous persons from passing on whether certain answers are marked wrong or right.

Can I get partial credit for an answer that is partially correct?

In general, the answer is no. By default, WebAssign marks an answer either wholly correct or wholly incorrect. If partial credit will be awarded, it is up to the creator of the assignment to set this up. Doing so requires a deeper level of programming than most question writers will undertake. So, the full answer is that partial credit is unlikely to be awarded for a particular question, but it may be possible (and available) in some cases.

WebAssign questions and question coding ^

Who creates the questions?

For the lecture courses, most of the questions are created by the publisher of the text for the course. An instructor may create or modify questions if needed, but this is unusual in the lectures.

For the labs, the questions are created by the faculty and graduate students in the UW physics department. This is because the questions need to be closely tied to the lab content, which is also created by the faculty members in the department.

The WebAssign company does not usually design the questions used in the assignments. Instead they provide a web interface for question writers, and they work with commercial publishers to create electronic versions of textbook problems.

I am sure that a question is incorrect. What can I do to get points for my answer?

If you are in fact sure that a question is incorrectly written, you should first discuss it with your TA and/or send an email to the instructor. If you are correct in your assessment, the question can be fixed, and everyone who has submitted an answer can be rescored. You should be aware, however, that in most cases, students are incorrect in their assessments of question validity.

WebAssign won't accept my answer, even though I am sure it is correct. What should I do?

First, exhaust the question of whether your answer is indeed correct. In most cases, you really do have the answer wrong, but you do not understand why. But, if you are convinced that your understanding of the question is correct, look for the following types of errors:

More information on problems that can occur when you answer numerical questions is given here. If you cannot determine what the problem is, send an email to your TA (best) or to the instructor (be prepared to wait).

How do I enter units?

You may enter units to numerical questions in a variety of formats. For example, seconds may be entered as "s", "sec", "second", or "seconds". You may also use equivalent units of the same type, for example, time could be entered as seconds, minutes, hours, days, weeks, etc, as long as the number in those units is correct (e.g., "1 min" or "60 sec" would be considered the same answer).

Mixed or compound units are entered as algebraic expressions, with the individual units acting like variables. For example, force an be entered as "newtons" or "N" or "kilograms*meters/(seconds*seconds)" or "kg*m/(s*s)" or "kg*m/s^2" or also "kg m/s^2" (note the space). However, a dash within a mixed unit is likely to be interpreted as a minus sign, and cause an error: "kg-m/s^2" will not work.

Remember there must be one space between the number and the unit: "9.81 m/s^2" is OK, but zero spaces, like "9.81m/s^2" is not.

Angular quantities also require a unit, even though an angle does not have a physical unit (some combination of mass, length time and/or charge). You may use degrees ("deg") or radians ("rad").

More information on units and WebAssign is given here.

How many significant figures should I enter?

If you do not have any other information about the number of significant figures that are expected, use 3 sig figs. Numerical answers in WebAssign are, by default, counted correct if the value is within 2% of the key. With 3 figures, you will obtain the required precision for the default tolerance.

However, and this is important, many questions do not use the default tolerance. In these cases, you should have some other information about what precision is needed. The question may explicitly state the number of digits needed. Or, the required precision is affected by a secondary value, for example, the uncertainty. If you are entering a value with an uncertainty, the following rules should apply:

  1. The uncertainty itself should have at most 2 significant figures.
  2. The value associated with the uncertainty should be stated to the same precision as the uncertainty, that is, both numbers should have the same number of decimal places.

More information on significant figures and WebAssign is given here.

Why does WebAssign check for sig figs sometimes and not other times?

The sig figs checking must be programmed into the question, it is not there by default. Thus it depends on how the question was coded. When you see this icon next to the entry box, , then you know that the sig figs are being checked.

Scoring and grading in WebAssign ^

Why does my essay question show zero points? I am sure that my essay is correct.

Essay questions are assigned a default score of 0 until they are graded by the TA. Essay questions cannot be graded automatically by the computer.

If the essay is still showing zero points more than three days after the assignment due date, send a note to your TA to request that it be graded.

I put in the same answers as my lab partner, and my question got marked wrong even though my partner's question got marked right. Why?

For automatically graded questions, this is impossible. The same question is delivered to all students, and the computer cannot tell who your partner is. More likely, there is in fact some difference between your responses and your partner's that you have not spotted. Look for differences in earlier entries, or a typographical or unit error. Many lab questions use earlier entries to calculate the key for later entries.

My answer is different from the key by only the last digit. Why do I lose all of the points for this part?

Yes, this feels unfair. But on WebAssign a question is either marked correct or incorrect; there is no middle value. Once the answer is outside of the tolerance range, it is considered incorrect, period. It is possible, with some effort, to allow for partial credit in some types of questions, but to make this work requires a lot of coding effort, so it is rarely implemented.

If you are worried about missing a question that you almost got right, just remember that the course grade depends infinitesimally on the answer to any specific question, the main thing is to keep the overall lab scores within the pack. (See below.)

I missed a lot of questions on the last assignment. How much will this affect my grade?

Probably not much. Any individual assignment does not affect the overall lab grade very much. If you are taking a 11x lab (117, 118 or 119), the lab grade is credit/no-credit, and if you have the necessary points to achieve credit, a poor assignment may make no difference in your final grade at all. If you are taking a 12x lab (121, 122, or 123), the lab grade is used to calculate your final overall course grade, and is given a 11% weight to that grade. Any given assignment can only amount to one-eighth of that (at most), so it can only affect your final grade by less than 2%.

The most important thing is to keep up with the course overall. If you have been "in the pack" with regard to your lab grades, you will be OK there. For 12x, your grade depends much more strongly on your hourly exam and final exam scores than on the lab, as long as you are passing the lab part.

Extensions ^

Why can't I have an extension on a Pre-Lab?

By design, Pre-Labs are supposed to prepare you for the activities you will do in the classroom. After you have done the experiment, the point of a Pre-Lab assignment is mostly lost.

Why is the extension on a Post-Lab available for only 1 week?

Post-Labs are designed to measure what you learned in the lab itself. In order to be effective, they need to be done shortly after the experiment is completed.

Can I use an extension to fix my mistakes?

No. Extensions are for when you have not attempted the work yet. After the due date, the solutions to many of the questions are visible. Using an extension to fix a Post-Lab is a form of cheating, and will be dealt with as such.