Demonstrating

This page is designed to be a resource for current and future demonstrators, with a core aim to inform demonstrators what is expected of them and provide resources for learning best-practice methods for teaching experimental physics. It will also serve as a "one-stop-shop" for queries that demonstrators (or their students) may have.

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Background

Demonstrators form a cornerstone of the experimental program at UTAS. Traditionally, academic members of staff have taught lab classes, with and without the assistance of post-graduate students providing additional teaching support. Labs are supposed to be a more laid back environment as compared to tutorials or lectures, and feedback from past and current students is that this is achieved when teaching staff are not academics. The ideal scenario for labs is therefore to have highly-trained, competent, and engaging postgraduate students to educate undergraduate students in the ways of experimental physics.

A description of the experimental program as of 2022 is listed below.

First-year physics - Part I labs

The first-year physics program is comprised of two physics subjects (KYA101 and KYA102 - details can be found here) with one subject running per semester and course subscription results in approximately 60 students. Labs are run as single experiments - that is all students complete the same experiment in a given session - with each experiment roughly synchronised with the course curriculum. Labs are run with two demonstrators, usually an experienced demonstrator being coupled with a new or less experienced demonstrator. The lab (Part I, room 236) has a capacity of 18 students and normally only three lab classes are required as distance students make up roughly 15% of students. Explicit details on the labs can be found either on the Teams channel or on POLUS

The first-year labs are coordinated by Danijela, but I think this is actually a responsibility that Danijela has taken upon herself. Ultimate responsibility for the labs falls to the unit coordinator.

Second-year physics - Part II labs

The second-year physics program is comprised of two physics subjects (KYA211 and KYA212 - details can be found here) with one subject running per semester and course subscription results in approximately 25 students. Labs are run as individual experiments - that is all students complete different experiments in a given session - with each experiment roughly corresponding to content which appears in the course that semester. Consequently, two distinct sets of experiments are offered in semester one and two. Labs classes are run with two demonstrators, usually an experienced demonstrator being coupled with a new or less experienced demonstrator. The lab (Part II, room 233) has a capacity of 18 students and normally two lab classes are run. Explicit details on the labs can be found either on the Teams channel or on POLUS

The second-year labs are coordinated by Andy, but again, this is a responsibility that I have taken upon myself. Ultimate responsibility for the labs falls to the unit coordinator.

Third-year physics - Part III labs

The third-year physics program is comprised of many physics subjects (details can be found here) with multiple subjects running per semester, some of which are elective subjects. Labs are tied to multiple subjects (KYA320 and KYA321) and are taught by individual academics, with most staff having responsibility for 1 or 2 labs. Course subscription results in approximately 10 students, so labs are managed in a very ad hoc manner, but the labs are also much more involved affairs with individual experiments running for a number of weeks and containing content which needn't appear in any course. Explicit details on the labs can be found either on the Teams channel or on POLUS

The labs are officially coordinated by Andy.

Responsibilities and expectations

Common to all levels of teaching a lab class, demonstrators have a number of responsibilities, which - in a vague "chronological" order - include:

• Taking class attendance: a check-in registration system is in place to allow students to mark their attendance, but this attendance should be verified as engagement is an assessable component of labs
• Supervise students: when teaching, a demonstrator has a duty of care over the students and any fellow demonstrators. This means having a working knowledge of procedures and how to access information in the event of an accident or emergency
• Teach students experimental physics: it is expected that you will have a sound knowledge of the experiments and associated physics, which includes troubleshooting the apparatus - we want to teach problem solving, and there is no better way to demonstrate the utility of the skill than with effective deployment of said skill.
• Have fun: enjoying yourself and conveying the wonders of the natural world is delightful, and genuine excitement for science, and knowledge more generally is often contagious, and that is something we really do want to spread (obviously one should do this in a COVID-safe manner)

Part I

Attend the weekly training and discussion meeting

Part II

• Train and master the experimental content before the commencement of classes before semester
• Complete log-book marking before the commencement of the following lab

Part III

• Attend the introductory session to meet students and spruik your experiment(s)
• Coordinate with students who wish to undertake the experiment for which you are responsible.
• Supervise the experiment. This includes:
  • Providing a safety induction for the experiment (if relevant)
  • Instructing students on the apparatus and guiding them through the experiment
  • Assessing the experimental logbooks produced by students
• Lab development is a core part of one's responsibilities. This means being across the current apparatus and procedure, and actively researching and developing the experiment, including improvements to the apparatus, the experiment and the support materials - which may mean developing them in the first place.

Assessment

General idea

With the introduction of logbook assessment rather than lab report assessment, marking guides that were previously used will have a diminished utility. Critically, assessment of a logbook requires that one be fluent in the ways of best-practice logbook creation and curation. An extensive guide has been prepared for students on how to write a log, what is expected of them, and a model logbook. Whilst this document is not purpose, I did spend time punctuating the report with the important aspects that undergird a quality log. These include:

• An introduction/background section. Whilst logs are to be written in something that approximates real time, it is incumbent on students to research what it is that they are going to do ahead of time, understand/explain the relevant physics, and outline the plan of conducting the experiment.
• Record keeping: recording of the date, partner(s), location, equipment, and other pertinent details

• A commitment to explaining what they do (or are going to do) and most importantly, why it is they do (or are going to do it). At all points, we seek to reward physical insight: this may be in the form of experimental design, execution or analysis and discussion, but making decision based on a science-based argument really is the currency in which experiments trade. I tend to extend this to anything and everything, for example, encouraging people to take detours from their explicit goals if there in an interesting question to answer, or some neat physics to be found. An example of this from the other day: in discussing ultrasonic bursts for range finding, we got on to what does the Fourier transform actually do for you in signal processing, and posed the question

  If I get a piece of wire, plug it in to the oscilloscope and look at the FFT, what will I see?

  having students actually do this, and discuss what it is they see and why they are seeing it is real-world physics. It is not part of the ultrasonic prac, but is likely both more interesting and more useful than anything in that experiment. The comment I am forever writing is

  where is the physics?

  so rewarding inquiry and reason-based approaches to experimentation is a the best way to inculcate quality scientific methods.

• Technical proficiency: people should not be punished for not knowing how to drive complex devices, especially given a failure to know how to use technical instrumentation can be laid (at least in part) at our feet. That said, the mastery of a tool or technique, especially when someone strives to understand how a given device functions, should be well rewarded.

• A demonstrated understanding of the relevant physics, the experiment, extraction of quantities of interest and their uncertainties. This is the meat and potatoes of most lab reports, so people will likely be tuned to reward quality content in the realm; however, if applicable, emphasis should be removed from calculating the "exact thing" that students are told to calculate and freedom granted for good investigative science.
• Reflection and feedback: adjusting one's thinking based on reasoning with oneself or with others should be rewarded. In all cases, detailed feedback for improvements should be provided in each assessment, and subsequent logs should have some assessment weighted to if and how this feedback has been incorporated. To streamline how this can be assessed, students are explicitly asked to comment on their adjustments in a reflections section. This does mean it is incumbent on assessors to provide both timely and detailed feedback.
• Log presentation: by their very nature, logs are not prescriptive, but rather they are a discourse with oneself, and therefore will be as unique in form and structure as the people the produce them. That said, there are good and bad ways of communicating and logically storing information, so whilst different styles should be accommodated, the content should be clear, easy to follow and well presented.
• The wishlist: I am staunchly against awarding bonus marks, but am in favour of rewarding the efforts of those that go above and beyond. These to things can look similar, but the difference tends to fall out as with the latter, one can never exceed 100%. In any case, committing acts of severe best-practice, for example, simulating the experiment, writing novel analysis code and/or putting code in a repository such as GitHub or GitLab, should be profoundly rewarded, be it in the form of high praise or in extreme cases, promotion of the content to the playhouse, a hub on the experimental physics website for exactly this kind of content, namely interesting extension material for the labs.

Cheat sheet

In an attempt to make a standardised assessment template, the following checklist may prove useful

• Background section (this should be completed before the first lab session) [10%]

  You needn't read through the whole thing, but rather verify it's existence, and then through chatting with the students verify if they understand the relevant concepts along with knowing how it is they are going to conduct the experiment.

• Experimental engagement, commitment and competency [30%]

  This comes from your interactions with the students throughout the experiment: are they engaged and doing experimenting well? This takes many shapes and forms, but attitude, effort and competency should be rewarded.

• Log book [60%, percentages below reflect the percentage of the total mark]

  • Experiment [30%]

    Have they performed a experiment good experiment? Have they appropriately employed the scientific method? Is their analysis sound? Are uncertainties appropriately accounted for and propagated as necessary? Are the results discussed, or simply displayed?

  • Physics [20%]

    Where is the physics? Have they discussed why they are doing things, or why things happened? Are the implications of the physics discussed, or are only narrow applications considered? Assertions should be justified, and the physics should be correct.

  • Reflections¹ [10%] Have they implemented the suggested changes improvements from other labs? These should be visible throughout the log, but should also be briefly discussed in a reflections section at the end of the report

Administration

Inductions and safety

As part of lab demonstrating, one must conduct various safety inductions. The strata of inductions are explained on the lab website, but the overall gist is that students must complete the university-wide induction, demonstrators must provide local-area inductions for lab classes (usually done during the first session) and when demonstrating a specific experiment, you must provide an experiment specific induction. These can have varying levels of formality, but it is important that any critical safety information be communicated clearly and concisely. The safety webpage on the lab site has most of the safety information that is specific to physics labs, but knowledge of the experiment specific hazards - especially at the third-year level - is the responsibility of the experiment demonstrator.

Induction template

When performing safety inductions, it is a good idea to not make it a download session of dry safety content. I typically use the phrasing of lab introduction and front load the session with a discussion of why experimental science is interesting, their experiences of experimentation, and how that maps onto what they think experimentation should be. With appropriate forced student interactions, this usually get people engaged and primed for actually taking in the important bits of safety: the stuff that is actually hazardous. For generic things, I direct people to the safety webpage and tell them only what they need know. Below, one can access a short presentation that I concocted for the introductory session for the part II labs in semester one, 2022:

Induction template

Attendance

Attendance is recorded to

1. Monitor attendance
2. Ensure prac allocations are balanced

and this is usually done with an auto-populating spreadsheet in teams, which should be checked and tweaked as necessary at the beginning of a class. Links to the spreadsheets can be accessed below:

• Part I attendance with the associated form
• Part II attendance with the associated form
• Part III attendance with the associated form

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1. This section is not relevant for the first experiment, and the marks should be allocated to the overall structure of the logbook. ↩

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Last update: April 28, 2022