Lab Exercises
During the course of the semester, we will peform the laboratory excercises listed at the left. The links will take you to additional information on each activity.
On Writing Scientific Reports
The following notes are based on information provided by Professor Steven Spangler at The University of Iowa Department of Physics and Astronomy when I was an undergraduate.
A scientific report is a clear, concise essay describing an experiment or series of observations. The paper should be terse but contain enough information for another investigator to reproduce the experiment: one of the hallmarks of a sound scientific theory is that experiments and observations be repeatable. Additionally, the fact that the report is for a scientific audience does not absolve the writer of the reponsibility of using proper English—sentences must be complete with well thought out ideas and must use proper syntax and grammar. Although it takes practice to perfect the style of writing required of scientific reports, the lessons learned may prove very valuable when called upon to present information later in life.
Although it may seem unnatural and is not accepted in other forms of narrative prose, scientific reports are typically written in the third person passive voice. This is preferable because observations, data, and results (i.e. the objects of the action) are more important than the observer.
Although students have some freedom in writing a scientific report, the paper should be based on the following format: (1) Abstract, (2) Introduction, (3) Procedure, ( 4) Observational/Experimental results, and (5) Conclusion. The individual sections are described in more detail below.
Abstract
The abstract is a brief synopsis of the experiment or observation. The
principle results should be summarized here and the abstract rarely
needs to be more than one paragraph in length. Below is an example:
Abstract: Observations of the binary star η Cassiopeiae were made using a Celestron 5 telescope. It was determined that the orbital period of the secondary component is 591 ± 55 yrs and at the present time the linear separation of the two components is 8.2 x 1014 ± 1.1 x 1014 cm ( 55 ± 5.7 A.U.). Further calculation indicates that the mass of the primary component is 4.8 ± 2.1 solar masses.
Introduction
The introduction should describe the reason the experiment is being performed
and what phenomenon is being studied. It should also briefly describe
the apparatus or materials being used (e.g. a telescope, data from the
astronomical almanac, etc.). For purposes of the lab reports in this
course, this section should be two or three paragraphs in length.
Procedure
This very important section includes a narrative that describes in detail
what the experimenter did. A narrative style is quite effective, but
it is important to be brief as well as clear. Equipment used should be
described as should how measurements were made. Any difficulties that
effected the results should also be described, particularly those that
are related to the equipment and techniques involved with the experiment.
Experimental or Observational Results
In this section the actual results of the experiment are presented. Much
of this information may be presented in the form of tables and graphs,
but the accompanying text should provide the context of the results
in a manner that ties the data together in a continuous and coherent
way. Tables should be numbered with Roman numerals and clearly labeled
(e.g. Table II. Distances to Galaxies). The column headings should
include proper symbolic notation (e.g. v (km/s)) and the text
should contain a verbal presentation of the information listed in the
tables or charts. An example of the narrative accompanying a data table
is given below:
"...t is the time the star was observed, δ is the declination of the star, and α is the angle through which the star drifted during the observation interval."
Graphs are used to display relationships between observed quantities such as the angular velocity across the sky and the declination of a star. The graph should be mentioned in the text and a brief summary of what it demonstrates should be included. Graphs should be numbered with Arabic numbers (e.g. Figure 6) and should include a caption that briefly describes the contents of the graph. Axes should be clearly labeled and numbered.
Results should also include errors or uncetainties in the obsevations or measurements.
Conclusions
In this section, the results of the experiments or observations should
be given as should what has been learned as a result of carrying out
the experiment. It is good practice to number the conclusions and place
them in a list. Below is an example:
"...the following was determined:
(1) The period of the secondary star was calculated to be...
(2) The linear separation of the two compenents was...
(3) The mass of the primary star was estimated to be..."
A final concluding paragraph or suggestions for further investigation may be included at the end.