In this exercise, you will apply the scientific method and critical thinking to a familiar, sometimes
misunderstood situation. You will plan and carry out your own observations and measurements
outside of class, and submit a report on your work.
The full moon is on February 24th so you will need to make your measurements sometime
between February 21st and February 27th. You can use programs like Starry Night or
viewing apps on your phone to check when the moon will rise to plan your observation but any
measurements must be made by hand. You can collect data with another person in the lab
but any written section of the lab must be done independently and you must clearly state
who you were working with.
If you have looked up at the full moon you may have noticed some of the variety of ways it can
appear in the sky. We have looked at the phases of the moon and eclipses in the ASTR courses
and labs before but here we want to look at the finer details of the moons appearance.
Specifically the apparent size of the moon during a full moon.
Your goal is to precisely measure the apparent size of the full moon in the sky over the course
of the night. You will follow the steps in the scientific method and document your process to
submit a written lab report. Be sure to read and follow the following instructions and rubric.
II. The Scientific Method
This is the process by which we develop explanations of the natural world and test them.
Generally, the process includes:
1) A problem or question to be addressed
2) A hypothesis (or educated guess as to what is happening, usually based on some
theory, and consistent with previous measurements or experiments)
3) An experiment or observation to test a prediction of the hypothesis
4) An analysis of the experimental data collected and any uncertainty in that data.
5) A conclusion, either that the hypothesis is consistent with the measurements, or that the
hypothesis is not supported by the measurements (a hypothesis cannot be completely
confirmed as the explanation from just one experiment).
Here are some additional details that are applicable to this particular activity.
1) The question we are asking is if the apparent size of the full moon in the night sky
changes as we view it at different times of the night.
2)Your hypothesis should clearly state if you think the apparent size of the moon will
change and why you think that. Statements supporting your rationale must be present
as part of your hypothesis.
3) Your experiment is measuring the apparent size of the moon at different times of the
night and thus different locations in the sky. You should have measurements from at
least 3 different times/heights above the horizon. These measurements must be as
precise as you can manage while accounting for uncertainty in your measurements. The
units of your measurements should be standard units (cm, mm,degrees, arcmin, arcsec).
You should have a measurement of both size and height above the horizon each time
you collect data.
4) Your analysis should include discussion of the uncertainty in your measurements and
how the uncertainty impacts what your data tells you about the apparent size of the
moon.
5) Your conclusion should summarize the results of your observations and state if the
results support or do not support your hypothesis. There is no proving a hypothesis true
from one experiment, we can only make statements of support.
Rubric:
Your report must include each of the sections mentioned below in the given order, clearly
labeled as such. Your report should be written in complete sentence paragraph structure in
each section. See the details for each section. To meet the section requirements your lab
should be about 2-4 pages in length.
Introduction:
The introduction should include your clearly stated hypothesis with supporting statements. You
can do as much research as you like to support your hypothesis. Be sure you are consistent in
your statements and your hypothesis is clear.
Procedure:
The procedure should begin with details on how you will measure the apparent size of the
moon.
Here are some details that must be included in your procedure description.
1) Tools/equipment you used to make your measurements and how you used them.
2) Units your measurements will be made in.
3) Actions you took to reduce error and uncertainty in your measurements.
4) Numerical uncertainty of your measurements (no such thing as 100% accurate
measurements).
Data and analysis:
This section should begin with well organized tables of the data you collected. Tables should
include what was measured, when it was measured and have the units clearly stated. It is
recommended you note the uncertainty of the measurements in or near the table.The analysis will follow the data tables and should be in complete sentence format. You should
clearly state what your data is showing based on the measurements and the uncertainty of the
measurements.
Conclusion:
This section is a summary of your experiment and results. Here you should state if your
observations supported or did not support your hypothesis. (You cannot make statements of
truth or prove a hypothesis with one experiment, do not make these statements).
You should also include ways to improve your experiment. This can include alternate (more
accurate) methods of measurement or other changes to the procedure to test the hypothesis.
