Moon%20Phases

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Moon Phases

• And some basic ideas about science and the
  scientific method

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Who can tell me

• What the moon looks like when you observe it?

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How were you able to draw the moon?

• Its not visible from here in the class room!
• You did it from memory?
• But lets say we want to know what the moons of
  Jupiter would look like from Jupiter?
• Would doing it from memory help?
• What we really want

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Is what scientists call a THEORY

• In this case a theory that can predict what (any)
  moon should look like when observed.
• Regardless of where the moon is and where it is
  observed from!

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THEORY

• In the context of science, the word THEORY has
  special meaning. The FreeDictionary says
• theory \the-?-re, thir-e\ Noun, plural
  theories
• 1. A set of statements or principles devised to
  explain a group of facts or phenomena, especially
  one that has been repeatedly tested or is widely
  accepted and can be used to make predictions
  about natural phenomena.
• 2. The branch of a science or art consisting of
  its explanatory statements, accepted principles,
  and methods of analysis, as opposed to practice
  a fine musician who had never studied theory.
• 3. A set of theorems that constitute a systematic
  view of a branch of mathematics.
• 4. Abstract reasoning speculation a decision
  based on experience rather than theory.
• 5. A belief or principle that guides action or
  assists comprehension or judgment staked out the
  house on the theory that criminals usually return
  to the scene of the crime.
• 6. An assumption based on limited information or
  knowledge a conjecture.

A set of statements or principles devised to
explain a group of facts or phenomena, especially
one that has been repeatedly tested or is widely
accepted and can be used to make predictions
about natural phenomena
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Conjecture and Hypothesis also have only one
meaning when used in a scientific sense

• conjecture
• 1. Inference or judgment based on inconclusive or
  incomplete evidence guesswork.
• 2. A statement, opinion, or conclusion based on
  guesswork.
• hypotheses
• 1. A tentative explanation for an observation,
  phenomenon, or scientific problem that can be
  tested by further investigation.
• 2. Something taken to be true for the purpose of
  argument or investigation an assumption.
• 3. The antecedent of a conditional statement.

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Its a fact

• You can NOT prove a theory to be true!
• In math, you can prove a theorem to be true
  that is something different

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By the way

• Galileo Galilei (1564 1642) is credited with
  formalizing what we now call the scientific method

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Models

• When scientists develop theories, they usually
  create a model to describe the physical
  observations they make
• Models dont have to be perfect, they only have
  to be good enough to cover the domain of the
  theory

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Lets play a game

• You are scientists and your job is to develop a
  theory
• You make an accidental observation
• From those observations you will make a
  hypothesis
• From the hypothesis you will create more
  experiments
• And repeat until you have a theory
• Remember, among other things a theory must have
  predictive value!

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Heres the universe and your accidental
observation
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?
TRUE
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Your turn
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Can you

• think of a theory that everyone was sure was
  correct but 228 years later was shown to not be
  correct?

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Newtons theory of gravity, 1687
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Einsteins theory of general relativity, 1915
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What we came here for

• Develop a theory that will predict what the moon
  will look like each day of the lunar cycle
• AND
• Where to find the moon in the sky given we know
  what it looks like

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How to measure and record your data

• Going to measure distance in fist widths
• This is about 10 degrees
• Were going to practice this in a few minutes
• Going to use the sun as your reference point
• Going to do this for 4 weeks

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NEVER, EVER
Look at the sun without specially designed eye
protection!
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What to record for your data

• Position of the moon relative to the sun
• Appearance of the moon
• Date/time observation made

Moon
Sun
6 fists
March 99, 2008 4PM
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Bonus items

• Sketch in the appearance of the markings on the
  moon
• Indicate in which direction(s) the sun and moon
  are (E, SE, S, SW, W) when you observed them

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How to measure

• Use one hand to cover the sun
• Measure in fists from the sun to the moon
• Measure 3 times, record each, and average them
• If they are far apart in the sky
• From horizon to horizon is 180 degrees or 18 fist
  widths
• So you can measure up from the horizon for both
  and subtract from 18.
• Remember horizon means straight in front of you,
  not the visible horizon (like tree tops, roofs,
  etc.)

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Hints

• Moon will rise today (17 Mar 08) at 238PM
• Each day it rises about an hour later (350PM on
  Tuesday, 359 PM on Weds)
• You will not get data every day
• Clouds, bed time, and ????
• Think about what your theory is, and the model
  that you might use to demonstrate the theory