Physics 331 Lab: An Introduction
You’ve spent many hours
in an academic laboratory setting, but this experience is intended to be
uniquely practical, often challenging, but ultimately rewarding.
Creative thinking,
observing physical phenomena under controlled experimental conditions, collecting
and processing data quantitatively and accurately, and experiencing the
challenges of collecting information in the face of experimental error and
variability – this is the intent.
Gaining experience in
designing an experiment to answer a question is the goal of several labs. We give you a question
and your team designs, through the use of creativity and background scientific
knowledge, a way to measure the proposal in an effort to answer the question.
Considering how your experimental design
affects the certainty of your results
will be of great importance.
Lab content often comes
before the material is covered in lecture. Consider this a benefit: Realistically, you often have no idea what will happen and must
explore a phenomenon experimentally. Discovering the behavior without knowing
the answer beforehand (e.g. all real scientific experiments) is a skill to be
gained in this instance.
Your results matter, but
the quantitative validity of your results is equally important. Repeated experiments never give the exact same results: variation is
inevitable. But an “answer” must be submitted, right? To combat variation, the “answer”
should always include a range of values which represent potential variation.
You conducted the experiment in a unique way. Consider where the
possibility for variation(s) lies and incorporate this into your “answer”
mathematically or qualitatively.
Learning how to share
results and ideas is part of the scientific-process. You will
present your results to the rest of the class, have them comment on your
results, and – likewise - you will comment on their results. The process of
many people analyzing and thinking about everyone’s work eventually leads to
the correct result and correct interpretation. This often occurs through a
scientific community/organization in the form of published papers or
presentations at seminars or conferences. Consider peer-evaluation a mild
introduction to critical peer-analysis aiming to produce ‘the best science’.
The Experiments
Prior To Lab:
Designing, carrying out,
and presenting your results can be time-consuming. Fortunately, you will have two
weeks to conduct most of the labs.
Read the Lab Before You
Come-In:
While You Are in Lab:
Document what you are doing in a lab-report-format as you proceed
throughout the experiment. Documentation must be shared with your lab partner(s).
Results must be retained by all parties involved. Consider utilizing mediums like
Google Drive to stay connected.
Lab Reports
Lab reports fulfill a number of purposes. The following are
of greatly emphasized throughout the course:
1.
Conveying
an understanding of the goal, describing methods, and portraying associated
theories.
2.
Reporting
experimental results, interpreting their meaning, and exploring the reason for
error.
3.
Presenting
information in an orderly and logical manner; neatly reflecting professionalism
exhibited in respectable publications. Using the appropriate number
of significant figures, including units, and labeling graphs appropriately are
examples of such conduct.
4.
Communicating
in a clear and unambiguous manner (i.e. present as much information with the
least amount of space). Imagine that you are the reader and want the bottom
line and the main point – not unnecessary filler. The report must be completed in
accordance with the syllabus - containing only the necessities. Small-font,
crowding, and margin-expansion is unacceptable.
Your grade will reflect how well you
have achieved these expectations.
*** Outline of a Typical Lab Report:
Use common sense as all the contents listed
may not apply to each laboratory report.
1)
Goals: Briefly state and
describe the goal of the experiment to be performed.
2)
Experimental
Approach: Describe
the strategy used and explain the logic of this strategy. This MUST include a
professional description of the methods used. Be concise. A
‘scientific-individual’ should be able to repeat your experiment based on your
methodological-descriptions. Do not explain the obvious, but include all
deviations from normal procedure.
3)
Theoretical
Expectations: Provide a theory which (often mathematically) models
the experiment and provides a reasonable prediction of the results based on
such theoretical model.
4)
Results
Presentation: Include
tables and graphs near the corresponding text (NOT at the end of the
report).
5)
Discussion: Interpret your results, discuss
the limitations of the methods used, explain agreement or disagreement between
experiment and theory, and explore changes which, in hindsight, might improve
the results. Depending on the circumstances, discuss anything else that may be
pertinent in retrospect.
Participation in Class Discussion
Critically evaluating your own experimental design is
hard! It is difficult to see how you could improve your experiment, and it
is natural to believe that your design
is the best design (if in reality it
is not). This is why we hold a class discussion during each lab—to help
you re-evaluate your experimental design. In doing so we hope that you develop
a sense of your own bias. In other words, try to eliminate the natural tendency
to make subjective ‘assumptions’ that potentially work against the objective.
A fair portion of your
grade depends on participation in both class presentations and discussions at
the end of the lab session. We are looking for you to make significant
contributions to other groups’ understanding of their lab, not just raising
your hand and asking “why didn’t you take more data?”
Grading
Your lab-grade is
essentially one-fourth of your overall grade for the course. The grade is based
1) on team lab reports, 2) on your individual participation in the lab, and 3) on
your participation in the collaborative class discussions during lab. ** Your
grade will not depend on whether your experimental
results align with theoretical expectations or accepted standards. Your grade will depend on how well you conceived
and carried out the experiment.
Attendance
Attendance at every lab
is mandatory. Contact your uTAs and/or the professor if
you anticipate missing a lab session. With a VALID WRITTEN EXCUSE, one may
perform a makeup activity at the end of the semester which will take at least
two hours and may involve doing a novel lab, evaluating data, etc. You may
participate in a makeup lab for a maximum of one excused absence.
Without a valid written excuse, you will get a zero for the particular lab. You
may receive a failing grade for the entire class (both lecture and lab) if more
than one lab session is missed.