"Young scientists should renounce the false modesty of their predecessors. Do not be afraid to name the agent of the action in a sentence, even when it is 'I' or 'we.' Once you get into the habit of saying 'I found,' you will also find that you tend to write 'S. aureus produced lactate' rather than 'Lactate was produced by S. aureus.'"
Barbara Gastel and Robert A. Day, How to Write and Publish a Scientific Paper,
Greenwood (2016), p. 202.
Preparation
Due 12:00 PM before start of lab
Prelab assignment 6 (*.html)
Equipment
rulers/metersticks (12", 1 m, 2 m)
wood boards of various lengths
(at least 20 different lengths in the range: 10 cm  2.00 m)
whiteboards, markers
laboratory laptop, PASCO Capstone
Microsoft Excel
Big Ideas
Abstracts in science concisely summarize research, and can be written in various formats. The falling time for a (nearly) vertical uniform bar released from rest depends on its length.
Goals
Students work in (selfassigned?) groups to evaluate actual published abstracts in terms of completeness, conciseness, and following an activevoice descriptive format.
Students build upon previous knowledge of graphing and curvefitting software, and best practices for data collection and graphical analysis.
Students execute a research task by taking and analyzing data, and write a conclusion and finally a descriptive abstract in a group lab report.
Tasks
(Record your lab partners' names on your worksheet for tasks 12, to be turned in at the end of today's lab for randomly selected grading for your group.)
1. Descriptive Abstracts
Lab reports in this course will use a terse descriptive abstract format, which is typically used for conference proceedings and research posters (in contrast to a longer, formal informative abstract format used for scientific journal papers)."A descriptive abstract indicates the type of information found in the work. It makes no judgments about the work, nor does it provide results or conclusions of the research. It does incorporate key words found in the text and may include the purpose, methods, and scope of the research. Essentially, the descriptive abstract describes the work being abstracted. Some people consider it an outline of the work, rather than a summary. Descriptive abstracts are usually very short—100 words or less."
"Abstracts," The Writing Center, University of North Carolina at Chapel Hill. Suggested guidelines for writing a descriptive abstract for lab reports in this course are listed below:
 Describes measurement made, equipment and methods used.
 Describes data analysis and mathematical modeling.
 Describes how mathematical model is validated with experimental values (or vice versa).
 Uses active voice and firstperson pronouns ("we" or "I"), instead of passive voice.
 Written in pasttense, instead of present, future, or mixedtense.
 Omits opinions and unnecessary facts.
 Avoids abbreviations, equations, and symbols.
 Omits specific numerical results, conclusions, and recommendations.
Use these guidelines to evaluate four sample abstracts below. (Note that not every guideline can be absolutely determined for these sample abstracts; at least pick out the most obvious practices that were followed or not followed, and it's okay to select "maybe" if you're uncertain. Also pace yourself to allow enough time today for the following "fallingstick" experiment.)
 Abstract (a):
"...Rapid deformations were studied by dropping masses onto one end of a Silly Putty cylinder, and slow deformations were studied by compressing the cylinder in a materials testing machine. The results were compared with a simple engineering model of viscoelastic materials to estimate the stiffness and the viscosity of the Silly Putty cylinder. It was found that stress induced in Silly Putty relaxes with a time constant of about 0.1 s, Young's modulus for a rapid deformation is about 1.7×10^{6} N/m^{2}, and the viscosity for a slow compression is about 8×10 Pa⋅s. When subject to a short impact, Silly Putty vibrates as a result of compressional wave propagation through the material."
Rod Cross, "Elastic and viscous properties of Silly Putty," American Journal of Physics, vol. 80 no. 10 (2012), p. 870. Were these best practices followed for abstract (a)? If "yes," then merely state so. If "maybe" or "no," give a brief explanation.
 Describes measurements/equipment/methods.
[ yes  maybe  no ]
 Describes data analysis/modeling.
[ yes  maybe  no ]
 Validates model with experiment.
[ yes  maybe  no ]
 Active voice, firstperson pronouns.
[ yes  maybe  no ]
 Written in pasttense.
[ yes  maybe  no ]
 No opinions, unnecessary facts.
[ yes  maybe  no ]
 No abbreviations, equations, symbols.
[ yes  maybe  no ]
 No specific numbers, conclusions, recommendations.
[ yes  maybe  no ]
 Abstract (b):
"...The radius of a rubber balloon is measured as it is cooled with liquid nitrogen. For balloons filled with simple gases that condense at liquid nitrogen temperatures, we found that the volume decreases linearly with time. We compared our measurements with a simplified model based on elementary kinetic theory and thermodynamics that explains this behavior. Students are encouraged to test the validity of the model by repeating the experiment using gas mixtures and gases that do not condense at liquid nitrogen temperatures."
A. J. Moreno, H. Ferrari, and V. Bekeris, "Cooling Balloons with Liquid Nitrogen," American Journal of Physics, vol. 78 no. 12 (December 2010), p. 1312. Were these best practices followed for abstract (b)? If "yes," then merely state so. If "maybe" or "no," give a brief explanation.
 Describes measurements/equipment/methods.
[ yes  maybe  no ]
 Describes data analysis/modeling.
[ yes  maybe  no ]
 Validates model with experiment.
[ yes  maybe  no ]
 Active voice, firstperson pronouns.
[ yes  maybe  no ]
 Written in pasttense.
[ yes  maybe  no ]
 No opinions, unnecessary facts.
[ yes  maybe  no ]
 No abbreviations, equations, symbols.
[ yes  maybe  no ]
 No specific numbers, conclusions, recommendations.
[ yes  maybe  no ]
 Abstract (c):
"A microwave oven operating at a frequency of 2.45 GHz was designed for demonstrating threedimensional standing waves. The threedimensional standing wave patterns formed on cobalt chloride paper placed at the center of the oven chamber were examined. The images on the cobalt chloride paper corresponding to antinodes of the standing waves were recorded by a digital camera after turning on the microwave oven. The results show that the numbers of antinodes of the standing waves in each plane agree with those of the theoretical calculation of the electric field distribution in the oven chamber."
S. Kamol, P. Limsuwan, and W. Onreabroy, "ThreeDimensional Standing Waves in a Microwave Oven," American Journal of Physics, vol. 78 no. 5 (2010), p. 492. Were these best practices followed for abstract (c)? If "yes," then merely state so. If "maybe" or "no," give a brief explanation.
 Describes measurements/equipment/methods.
[ yes  maybe  no ]
 Describes data analysis/modeling.
[ yes  maybe  no ]
 Validates model with experiment.
[ yes  maybe  no ]
 Active voice, firstperson pronouns.
[ yes  maybe  no ]
 Written in pasttense.
[ yes  maybe  no ]
 No opinions, unnecessary facts.
[ yes  maybe  no ]
 No abbreviations, equations, symbols.
[ yes  maybe  no ]
 No specific numbers, conclusions, recommendations.
[ yes  maybe  no ]
 Abstract (d):
"We analyze the motion of a gravitypowered model race car on a downhill track of variable slope. Using a simple algebraic function to approximate the height of the track as a function of the distance along the track, and taking account of the rotational energy of the wheels, rolling friction, and air resistance, we obtain analytic expressions for the velocity and time of the car as functions of the distance traveled along the track. Photogates are used to measure the time at selected points along the track, and the measured values are in excellent agreement with the values predicted from theory. The design and analysis of model race cars provides a good application of principles of mechanics and suggests interesting projects for classes in introductory and intermediate mechanics."
Vincent P. Coletta and Jonathan Evans, "Analysis of a Model Race Car," American Journal of Physics, vol. 76 no. 10 (2008), p. 903. Were these best practices followed for abstract (d)? If "yes," then merely state so. If "maybe" or "no," give a brief explanation.
 Describes measurements/equipment/methods.
[ yes  maybe  no ]
 Describes data analysis/modeling.
[ yes  maybe  no ]
 Validates model with experiment.
[ yes  maybe  no ]
 Active voice, firstperson pronouns.
[ yes  maybe  no ]
 Written in pasttense.
[ yes  maybe  no ]
 No opinions, unnecessary facts.
[ yes  maybe  no ]
 No abbreviations, equations, symbols.
[ yes  maybe  no ]
 No specific numbers, conclusions, recommendations.
[ yes  maybe  no ]
 Discuss which of the above abstract(s) (a)(d) you consider the most complete in terms of the content guideline(s) (i)(iii), and specifically why.
Abstract(s): __________.
Brief explanation:
 Discuss which of the above abstract(s) (a)(d) you consider the most compliant with the stylistic guideline(s) (iv)(viii), and specifically why.
Abstract(s): __________.
Brief explanation:
2. Falling Stick Times (preliminary setup) Set up a 0.10 m and a 1.00 m stick (these lengths may be approximate) such that they are just about to tip over, and then release them. (You may need to have something placed on the floor such that their base will pivot in one place, and use a shim to set a consistent release angle.) Which stick falls onto the ground first?
Stick with shortest falling time: [ 0.10 m stick  1.00 m stick ]
 Time the fall for a meter stick (or any stick approximately 1 m in length), by either by timing consecutive falls, and/or using people with multiple timers for the same fall (or a mixture of consecutive falls with multiple timers). Measure five fairly consistent values for the maximum falling time and record these values below.
Falling time for a 1.00 m stick
Trial → 
1 
2 
3 
4 
5 
falling t (s): 





 Calculate the average of these five measurements (keep the raw result for now, to be truncated later).
Average falling t = __________ s.
 Calculate the standard deviation σ of these five measurements, which is a measure of the "spread" of these data points (assuming that the error is random in nature). Use WolframAlpha (*.html) to calculate the standard deviation, by replacing the example numbers in the text box with your data points from above (keep the raw result for now, to be truncated later).
Standard deviation σ_{t} = __________ s.
 The standard deviation of the random experimental errors can be considered the uncertainty of the average. Truncate/round the average and standard deviation of the falling time to one uncertain significant figure.
Data set falling t = __________ ± __________ s.
 Compare the uncertainty of an individual falling time measurement (0.1 s? 0.01 s?) with the standard deviation of your repeated falling time measurements. The general rule to determine if a measurement can just be done once, or needs to be repeated (to find an average and standard deviation) is:
If trial measurements seem to vary by more than twice the value of the measurement uncertainty, then a number of repeated measurements should be made to determine an average value, until the standard deviation is comparable in value to the measurement uncertainty. (Or due to time constraints in this course, up to a maximum of 35 repeated measurements, if necessary.) Write a concluding statement discussing whether repeating this measurement only five times was sufficient in this case, and specifically why. Include the specific relevant numbers in this statement, such that it can be read (and cited) on its own without referring to the above calculations and numbers.
Brief concluding statement:
3. Modeling Falling Stick Time
(Done on whiteboard only, to be worked on and presented as a group.) Develop an experimental trendline equation of how the falling time (dependent variable) of a nearlyvertical stick released from rest depends on its length (independent variable), starting with an approximately 0.10 m long stick. Refer to the example data table below to create your spreadsheet; add more columns as necessary. (Do not enter the "A..." column headings and "1..." row headings, as those are just Excel spreadsheet "coordinates.") Create a detailed, stepbystep description of evidence that needs to be collected, and calculations to be donenot just "time each falling stick," but exactly what would someone need to do, stepbystep, to accomplish this. (Specifically, outline how many falls and/or different timers are used to collect data.)
Falling time vs. stick length
 A  B  C  ...  ...  ... 
1 
Stick length L (m) 
fall t trial 1 (s) 
fall t trial 2 (s) 
... 
Average fall t (s) 
Std dev (s) 
2 






3 






4 






5 






6 






7 






8 






9 






10 






11 






(Refer to the previous labs for instructions on how to generate a graph with independent and dependent variables in nonadjacent columns, with error bars.)
 Print out one copy of your data table, and print out one copy of your graph (with trendline equation and error bars); you do not need to record the data table or draw the graph on a whiteboard. Note that you should follow the suggested bestpractice guidelines for data collection and graphical analysis:
 Minimummaximum data range (spanning a factor of at least 5×, 10× is better).
 Has minimum number of data points (10).
 Concentrated data in rapidly changing portions of graph.
 Variable data points should be an average of repeated measurements (35 maximum), with a standard deviation reported in the data table, and represented with vertical error bars on the graph.
 Outlying data points should be replaced/removed.
 Proper choice of trendline fit type (in this case, linear, as you are testing a law of proportionality).
 Write out a concluding statement on the whiteboard regarding the validity of your mathematical modeltesting it by measuring the falling time using a stick length greater than your maximum experimental stick length, and comparing the percent discrepancies between the measured falling time, and predicted falling time from your trendline equation. Include the specific relevant numbers in this statement, such that it can be read (and cited) on its own without referring to the above calculations and numbers.
 After your procedure, data analysis, and concluding statement sections are complete, write out a descriptive abstract for your experiment. Note that you should follow the suggested bestpractice guidelines for content ((i)(iii)) and style ((iv)(viii)):
 Describes measurements/equipment/methods.
 Describes data analysis/modeling.
 Describes how model is validated with experiment.
 Use of active voice, firstperson pronouns.
 Written in pasttense.
 No opinions, unnecessary facts.
 No abbreviations, equations, symbols.
 No specific numbers, conclusions, recommendations.
 Bring up your whiteboards to the front of the class, to be presented to the instructor, which should include:
 A descriptive abstract.
 Stepbystep procedure.
 Data table, calculations and/or results.
 Evidencebased conclusion statement.
 Documentation Rubric (tasks 12)
(Graded from randomly selected group member)
Score  Description 
3  Explanations complete and calculations correct, or very nearly so. 
2  Essentially complete; few explanations/calculations missing or incorrect. 
1  Substandard effort; substantive amount of explanations/calculations missing or incorrect. 
0  Unacceptable or no significant effort. 
 Whiteboard Rubric (task 3)
(Graded as a group, evaluated by instructor during debrief session)
Score  Description 
3  Complete, thorough, understandable, with little or no clarification needed during verbal instructor critique (can be resubmitted and presented again with requested corrections/revisions made, and still receive full credit). 
2  Minor problems; some corrections/revisions requested by instructor still needed, but not completed during time remaining in lab. 
1  Minimally acceptable effort, essential/critical revisions still needed. 
0  Unacceptable or no significant effort beyond experimental work. 
Followup
Complete this week's postlab assignment, next week's prelab assignment, and review lab instructions.
Due 12:00 PM before start of next lab
Postlab assignment 6 (*.html)
