AST 191 Inquiry Project, Spring 2018
Background
Why this project? – AST 191 is part of the UK Core curriculum. In particular, AST 191 is one
of the courses in Intellectual Inquiry in the Natural, Physical and Mathematical Sciences.
Therefore, the course must include a student project that involves data collection and analysis so
that students gain further insights into how science works. Ever done a science fair project? The
project described below resembles a science fair project in some ways since it involves making
testable predictions, gathering data, interpreting the data and drawing conclusions. However,
you need not think up your own project since a suitable project is described in detail below.
Please submit your own work – Students are welcome to talk with each other and share ideas
on this project. Of course, you may also consult the Internet for explanations of lunar phases (e.g.
Wikipedia). However, each submitted project report should be the student’s own work in his or
her own words. Verifiable cases of plagiarism, if any, will be dealt with according to university
policies on these matters.
Important information
• Course credit of 10% – This project is worth 10% of your final grade, as specified in the
course syllabus. If you make a reasonable effort on this project, follow the instructions,
make no serious omissions, and turn in your report on time, you are likely to earn the full
credit. (The instructor wants you to succeed with this project!) You can also earn bonus
points on this project. Please see the end of this document.
• Time commitment of only a few hours – The instructor has designed this project to be
economical of your time, realizing that you have many other academic responsibilities.
However, the project does offer you the opportunity to gain experience in scientific methods.
The instructor estimates that this project should take no more than 8 hours total of your time
between now and the due date. Students may be able to complete the project in a satisfactory
manner in less time.
• Submission of your project to Canvas as a pdf file by April 23 – Submit your project to
Canvas as a single pdf file by 11:59p, Monday, April 23, 2018. (See the submission
instructions at the end of this document.) Each day of delay in submission will result in the
loss of 2% of the available credit (i.e. one day late means 8% credit at most). This rule is
essential so that graders will be able to assess projects in time for final grade calculations.
• This is not a “recipe” type of project – The instructor provides below a number of
instructions for completing the Moon phases project. However, these instructions are not
intended to be a recipe for exactly what to do. The instructions for data interpretation have
deliberately been left open ended to allow you to develop your own thoughts and
interpretations. In scientific research, it is often not clear just how to proceed. Scientists
usually have to figure out by themselves how to proceed in a research project.
Instructions for the Moon phases inquiry project
Please follow the steps outlined below to complete your inquiry project on Moon phases. Please
read the instructions carefully!
Two models to explain Moon phases
Oftentimes in science, more than one “model” or explanation for a natural phenomenon can be
imagined. In these cases, scientists devise testable predictions of the various models. Then
scientists conduct experiments or observations of nature to see which predictions are most
closely borne out. The model whose predictions are best borne out in nature is then considered
most likely to be correct. (Of course, it is possible that none of the imagined models is correct.
In this case, scientists must scratch their heads and think of yet new models.)
For example, consider the cause of phases of the Moon. When most people are asked about
phases of the Moon, they offer one of two explanations or “models”.
1. Moon phases are caused by the shadow of the Earth on the Moon – According to this
model, the Earth casts its shadow on the Moon. At different times, the Earth’s shadow
covers more or less of the Moon, thus accounting for the different phases of the Moon.
2. Moon phases are caused by different angles between the Moon, Earth and Sun –
According to this model, the angle between the Moon and Sun changes over time. As a
result, we see different fractions of the Moon’s illuminated hemisphere at different times,
thus accounting for the different phases of the Moon.
Recall that a model in science is a conceptual description of some phenomenon in nature. (For
example, we talked about the “celestial sphere” model in class, even though we know that this
particular model is not literally correct.) In this inquiry project, you will be asked to develop
testable predictions for each of the two Moon phase models above. Then you will be asked to
gather data, as described below, and test your predictions to determine which model best fits
your predictions. In so doing, you will be learning about how science works.
• An example of a model and a testable prediction – Suppose this project were about
seasons. Then your model might be as follows: “The Earth goes around the Sun in an
elongated orbit, causing the distance between the Earth and Sun to vary significantly during
the year. This yearly variation in Earth-Sun distance causes seasonal variations in
temperature on the Earth.” A testable prediction might be as follows: “Everywhere on
Earth, temperatures should be highest on about the same date of the year, namely the date
when the Earth is closest to the Sun. Therefore, summer should take place all over the Earth
at around the same time of year.” Note that this particular model is false. Nonetheless, if the
project were about seasons, you could gather temperature data throughout the year for
various locations on Earth (Northern and Southern Hemispheres), compare these data with
your prediction, and infer that the model is false. Then you would try to create another
model about seasons for which the testable predictions were verified by the data.
Ready? Please follow steps 1- 4 below. Don’t worry if everything is not 100% clear to you,
especially when you first read these steps. Things are rarely 100% clear in science, especially at
the beginning of an investigation.
1. Develop testable predictions for the moon phase models
Think about testable predictions for Moon phases, based on the two Moon phase models listed
above. By comparing your predictions with naked eye Moon observations and, especially, with
web data on Moon phases, you can argue which model above is correct. Of course, you may
already know which model is correct. If so, good for you! Nonetheless, you are asked in this
inquiry project to clearly demonstrate why you think one Moon phase model is correct and the
other is incorrect.
To help you develop testable hypotheses for both models, recall that the Moon orbits the Earth in
about one month’s time. Then consider these questions:
• If Moon phases are caused by the shadow of the Earth on the Moon (model 1), where do you
predict the Moon should lie in its orbit when the Moon is new? (It might help you to make a
simple drawing of the Earth, the Moon’s orbit about the Earth, and the Sun off to one side.
Your drawing need not be to scale.) What will be the angle between the Sun and the Moon
in the sky at new Moon? Note that new Moon is the phase in which all of the Moon’s face is
dark in our Earthly sky. So in model 1, the Moon must be entirely in the shadow of the Earth.
• If Moon phases are caused by the shadow of the Earth on the Moon (model 1), is the Moon
full for most of the lunar month, for part (say, about half) of the lunar month, or for only a
small fraction of the lunar month (say, a day)?
• If Moon phases are caused by different angles between the Moon and Sun (model 2), then
how should the illuminated fraction of the Moon’s face be related to the angle between the
Sun and the Moon in the sky? For example, when half of the Moon’s illuminated
hemisphere is visible from Earth (“half moon” in popular language), what should the angle
be between the Sun and Moon in the sky?
• If Moon phases are caused by different angles between the Moon and Sun (model 2), is the
Moon full for most of the lunar month, for part (say, about half) of the lunar month or for
only a small fraction of the lunar month?
To Do – Using the questions above and/or your own ideas, develop two testable predictions for
each of models 1 and 2. You should briefly explain your reasoning for each of these testable
hypotheses.
2. Gather Moon phase data from a website
• Where to find Moon data on the internet – Information about the Moon is available at the
U.S. Naval Observatory website http://aa.usno.navy.mil/data/.
• Get data for a specific date of the year – Go to this site and choose Complete Sun and
Moon Data for One Day near the top of the webpage. Insert the requested information into
Form A – U.S. Cities or Towns on the webpage, and then click on Get data to see the results
for a specified location and date. Chose Lexington Kentucky as your location. During
Daylight Savings Time, the times given for moonrise, etc. are in Eastern Daylight Time.
Subtract one hour to convert to Eastern Standard Time (EST).
• Generate data tables for all year – You can generate a table of moonrise & moonset times
and a separate table of sunrise & sunset times for all dates in 2018. To do so, go back to the
homepage cited above and click on Table of Sunrise/Sunset, Moonrise/Moonset… Specify
Year, Type of table and Lexington KY. Then click on Compute Table. The requested table
(sunrise/sunset or moonrise/moonset) will appear in your browser, and you can save it to
your computer. Times in these tables are all in EST.
• What information to record from the website – Gather data for every other day over a
period of a month (that is, data for about 15 different days, spanning a total period of about
30 days). If your last (i.e. family) name begins with “A”, begin gathering web data for April
1, 2018. (So you will gather data for April 1, 3, 5…) If your last name begins with “B”,
begin gathering web data for April 2, 2018. (So you will gather data for April 2, 4, 6…)
And so on. If your last name begins with Z, begin gathering web data for April 26, 2018.
(So you will gather data for April 26, 28, 30, May 2, 4…) For each day that you choose,
record the following information in a table: (a) date; (b) time of moonrise for that day,
Eastern Standard Time (EST), 24 hour clock; (c) phase of the Moon, e.g. waxing crescent;
(d) per cent of the Moon’s visible disk illuminated, and (e) time of sunrise.
A spreadsheet file to help you – If you wish, you may record your website data in the Excel
spreadsheet file Moon Phases Data AST 191 S18.xls. You will find this file on Canvas.
Choose the Canvas Menu item Files. Note the comments in the top row of the worksheet.
When entering times of moonrise and times of sunrise, take the information from the tables of
moonrise/moonset and sunrise/sunset described in the bulleted item immediately above. For
some dates (e.g. April 5, 2018), the moon does not rise in the 24 hour period of that day. For
these dates, leave your moonrise entry in the table blank.
3. Analyze and interpret your data for Moon phases
• Connections among the data you have gathered – Consider the data you have gathered
from the Internet about time of moonrise, time of sunrise, phase of the Moon and the per cent
of the Moon’s visible disk illuminated. What connections can you find among these data?
Consider, for example, the differences in times between sunrise and moonrise for the 15 or so
days. (You should calculate the differences in these times. Take, for example, the time of
moonrise minus the time of sunrise.) How are these time differences related to other data
about Moon phases? If you are reasonably familiar with Microsoft Excel, you may want to
make a graph or two of the moonrise – sunrise time differences versus other data on Moon
phases.
• Comparison of the data with the Moon phase models and your testable predictions –
How well are your testable predictions for the two Moon phase models borne out by the data
you have gathered (data from observations of Moon phases in the sky and, especially, data
from the internet)? Which Moon phase model is more consistent with your predictions and
why? If you had more time to complete this project, what additional data might you have
used to further test your model’s predictions?
• A useful suggestion – If you are at least moderately familiar with Excel (or whatever
spreadsheet program you use for this project), try creating another column in your
spreadsheet called Time Difference. In this column, calculate the time of moonrise minus the
time of sunrise. Then make a graph of Time Difference (on the X-axis) versus % of Moon
illuminated (on the Y-axis). Show this plot in your report and describe its significance to the
two models of moon phases. Of course, this plot will only be consistent with one of the
models because only one of the models is correct!
4. Write your report and submit to Canvas by Monday, April 23, 2018
• What to put in your report – Your report should consist of each of the four sections
outlined below. The credit to be assigned to each section is also listed. The instructor
envisions that reports on this project would typically be about 5-6 pages long, including
tables. However, grades for the report will be based solely upon how well you follow the
instructions for the project and carry out the requested data analysis, not upon the length of
the report. If you submit a shorter but thoughtful report that covers the important elements of
this project, you will receive full credit. Of course, there is no penalty for submitting a
somewhat longer report.
• How to submit your Inquiry Project report to Canvas as a single pdf file – Your report
must be submitted to the course Canvas site as a single pdf file. If you do not know how to
create a single pdf file, please consult on-line help or ask a friend. To submit your report,
choose Assignments in the Canvas menu on the left side of the course homepage. Then
choose the Inquiry Project assignment. Click on Submit Assignment, upload your pdf file,
and then click on Submit Assignment again.
Report sections (10% total credit)
1. Testable predictions for the two models (4%) – You should think of at least two testable
predictions for each model of Moon phases described earlier in this document. Briefly
explain your reasoning for the predictions you make for each model.
2. Data from the website on moonrise, sunrise, etc. for every other day over a period of a
month (2%) – These data, too, should be given in table form, extracted, if you like, from the
Excel spreadsheet file you may have used to record your information. Again, include a brief
text describing your table.
3. Analysis of the data (4%) – Discuss the questions outlined above in the section above
Analyze and interpret data for Moon phases.
Possible bonus credit!
Students who follow the instructions above with reasonable attention are quite likely to receive
full credit for this project. However, students who show evidence of additional effort in data
collection and, especially, in data analysis and interpretation are eligible for up to 3% of bonus
credit.
