Moon Phases

And some basic ideas about And some basic ideas about science and the scientific methodscience and the scientific method

Who can tell me…

What the moon looks like when you What the moon looks like when you observe it?observe it?

How were you able to draw the moon?

It’s not visible from here in the class room!It’s not visible from here in the class room!You did it from memory?You did it from memory?But let’s say we want to know what the But let’s say we want to know what the

moons of Jupiter would look like from moons of Jupiter would look like from Jupiter?Jupiter?Would doing it from memory help?Would doing it from memory help?

What we really want…What we really want…

Is what scientists call a THEORY

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

is observed from!is observed from!

THEORY In the context of science, the word In the context of science, the word THEORYTHEORY has special meaning. The has special meaning. The

FreeDictionary says:FreeDictionary says: the·o·ry \`thē-ə-rē, `thir-ē\ the·o·ry \`thē-ə-rē, `thir-ē\ Noun, pluralNoun, plural the·o·ries the·o·ries 1. 1. A set of statements or principles devised to explain a group of facts or 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 phenomena, especially one that has been repeatedly tested or is widely accepted and can be used to make predictions about natural phenomena.accepted and can be used to make predictions about natural phenomena.

2. 2. The branch of a science or art consisting of its explanatory statements, The branch of a science or art consisting of its explanatory statements, accepted principles, and methods of analysis, as opposed to practice: accepted principles, and methods of analysis, as opposed to practice: a fine a fine musician who had never studied theorymusician who had never studied theory..

3. 3. A set of theorems that constitute a systematic view of a branch of A set of theorems that constitute a systematic view of a branch of mathematics.mathematics.

4. 4. Abstract reasoning; speculation: Abstract reasoning; speculation: a decision based on experience rather than a decision based on experience rather than theory.theory.

5. 5. A belief or principle that guides action or assists comprehension or judgment: 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 staked out the house on the theory that criminals usually return to the scene of the crime.the crime.

6. 6. An assumption based on limited information or knowledge; a conjecture.An assumption based on limited information or knowledge; a conjecture.

A set of statements or principles devised to A set of statements or principles devised to explain a group of facts or phenomena, explain a group of facts or phenomena, especially one that has been repeatedly tested especially one that has been repeatedly tested or is widely accepted and can be used to make or is widely accepted and can be used to make predictions about natural phenomenapredictions about natural phenomena

Conjecture and Hypothesis also have only one meaning when used

in a scientific sense con·jec·ture con·jec·ture

1. 1. Inference or judgment based on inconclusive or Inference or judgment based on inconclusive or incomplete evidence; guesswork.incomplete evidence; guesswork.

2. 2. A statement, opinion, or conclusion based on A statement, opinion, or conclusion based on guesswork.guesswork.

hy·poth·e·seshy·poth·e·ses 1. 1. A tentative explanation for an observation, A tentative explanation for an observation,

phenomenon, or scientific problem that can be tested phenomenon, or scientific problem that can be tested by further investigation.by further investigation.

2. 2. Something taken to be true for the purpose of Something taken to be true for the purpose of argument or investigation; an assumption.argument or investigation; an assumption.

3. 3. The antecedent of a conditional statement.The antecedent of a conditional statement.

It’s a fact…

You can NOT prove a You can NOT prove a theorytheory to be true! to be true!

In math, you can prove a theorem to be In math, you can prove a theorem to be true – that is something differenttrue – that is something different

By the way…

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

Models

When scientists develop theories, they When scientists develop theories, they usually create a model to describe the usually create a model to describe the physical observations they makephysical observations they makeModels don’t have to be perfect, they only Models don’t have to be perfect, they only

have to be good enough to cover the domain have to be good enough to cover the domain of the theoryof the theory

Let’s play a game You are scientists and your job is to develop a You are scientists and your job is to develop a

theorytheory You make an accidental observationYou make an accidental observation From those observations you will make a From those observations you will make a

hypothesishypothesis From the hypothesis you will create more From the hypothesis you will create more

experimentsexperiments And repeat until you have a theoryAnd repeat until you have a theory

Remember, among other things a theory must have Remember, among other things a theory must have predictive value!predictive value!

Here’s the universe and your accidental observation

2

4

6

?TRUE

Your turn…

Can you…

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

Newton’s theory of gravity, 1687

Einstein’s theory of general relativity, 1915

What we came here for…

Develop a theory that will predict what the Develop a theory that will predict what the moon will look like each day of the lunar moon will look like each day of the lunar cyclecycle

AND…AND…Where to find the moon in the sky given Where to find the moon in the sky given

we know what it looks likewe know what it looks like

How to measure and record your data

Going to measure distance in fist widthsGoing to measure distance in fist widthsThis is about 10 degreesThis is about 10 degreesWe’re going to practice this in a few minutesWe’re going to practice this in a few minutes

Going to use the sun as your reference Going to use the sun as your reference pointpoint

Going to do this for 4 weeksGoing to do this for 4 weeks

NEVER, EVER…

Look at the sun without specially designed eye protection!

What to record for your data

Position of the moon relative to the sunPosition of the moon relative to the sunAppearance of the moonAppearance of the moonDate/time observation madeDate/time observation made

SunMoon

6 fists

March 99, 2008 4PM

Bonus items

Sketch in the appearance of the markings Sketch in the appearance of the markings on the moonon the moon

Indicate in which direction(s) the sun and Indicate in which direction(s) the sun and moon are (E, SE, S, SW, W) when you moon are (E, SE, S, SW, W) when you observed themobserved them

How to measure Use one hand to cover the sunUse one hand to cover the sun Measure in fists from the sun to the moonMeasure in fists from the sun to the moon

Measure 3 times, record each, and average themMeasure 3 times, record each, and average them If they are far apart in the skyIf they are far apart in the sky

From horizon to horizon is 180 degrees or 18 fist From horizon to horizon is 180 degrees or 18 fist widths…widths…

So you can measure ‘up’ from the horizon for both So you can measure ‘up’ from the horizon for both and subtract from 18.and subtract from 18.

Remember horizon means straight in front of Remember horizon means straight in front of you, not the visible horizon (like tree tops, roofs, you, not the visible horizon (like tree tops, roofs, etc.)etc.)

Hints

Moon will rise today (17 Mar 08) at Moon will rise today (17 Mar 08) at 2:38PM2:38PM

Each day it rises about an hour later Each day it rises about an hour later (3:50PM on Tuesday, 3:59 PM on Weds)(3:50PM on Tuesday, 3:59 PM on Weds)

You will not get data every dayYou will not get data every dayClouds, bed time, and ????Clouds, bed time, and ????

Think about what your theory is, and the Think about what your theory is, and the model that you might use to demonstrate model that you might use to demonstrate the theorythe theory