The Scientific Method

iSkylab

• Went really well!• Data 10, Form 3, Questions 7, explain ½, wrt, etc.• Type and repeat questions!• Moon phases are NOT due to shadow of the Earth!• If you say “we know that…” explain how you

know: from your data, from books,…• No “feelings”, please!• Criticism is meant to be helpful; might sting…

Activity: Kepler’s 2nd law

• Get out your worksheet books• Form a group of 3-4 people• Work on the questions on the sheet• Fill out the sheet and put your name on top• Hold on to the sheet until we’ve talked about

the correct answers• Hand in a sheet with the group member’s

names at the end of the lecture • I’ll come around to help out !

Activity: Kepler’s 3rd law

• Get out your worksheet books• Form a group of 3-4 people• Work on the questions on the sheet• Fill out the sheet and put your name on top• Hold on to the sheet until we’ve talked about

the correct answers• Hand in a sheet with the group member’s

names at the end of the lecture • I’ll come around to help out !

The Scientific Method• Systematized by Francis

Bacon, Descartes and Galileo in the 17th century

• Not the only way of knowing, but a very successful one

• A method to yield conclusions that are independent of the individual

• Conclusions are based on observation

Francis Bacon (1561-1626)

Contemporary of Shakespeare,

Elizabeth I, Kepler and Galilei

Rejects Aristotelianism and Scholasticism

Major Work:• Novum Organum (1620) (“New Tools”, the old Organum was Aristotle’s)

Francis Bacon (1561-1626)

Novum Organum Title:

Allegory on the daring mind: A Ship passes

through the “pillars of

Hercules”, beyond old

knowledge.

Rene Descartes – The RationalistDescribed the method to do science,

known for his mind-body dualism

Major Works:• Discourse (1637) [full title: Discours

de la méthode pour bien conduire sa raison et chercher la vérité dans les sciences]

• Meditations on first Philosophy (1641) [6 Meditations: Of the Things that we may doubt;

Of the Nature of the Human Mind; Of God: that He exists; Of Truth and Error; Of the Essence of Material Things; Of the Existence of Material Things; Of the Real Distinction between the Mind and the Body of Man]

Rene Descartes (1596-1650)

Rene Descartes’ Discourse

Describes the method to do science in a straightforward way (see below)

Major points:

• Science must be based on correct reasoning (logic)

• Science must be formulated in mathematical language

Starting line: “Good sense is the most evenly distributed thing in the world, for all people suppose themselves so well provided with it that even those who are the most difficult to satisfy

in every other respect never seem to desire more than they have.”

WUP 02: Describe, in your own words, the four principal rules of Descartes’ method of rightly conducting one's

reason and of seeking truth in the sciences.• Scooby-Doo: 1. Never believe something that you have not seen clearly

and without doubt for yourself. 2. Break problems down into parts so that they can be solved as adequately as possible. 3. Start by working with the simplest and easiest things and work your way up to the more difficult and complex things. 4. Make reviews and summaries so complete and general that it is not possible to leave something out.

• Silver: Descartes' method of conducting one's reason and discovering actual truth in the sciences first involves not accepting any bit of knowledge as fact unless it is without a doubt accurate. Second, partition the issue under examination into as many pieces as possible to best help reach a legitimate conclusion. Third, once an issue is split into separate problems to investigate, a person must start with the simplest and easiest to know truths and facts about the problem and build up from there to reach complex conclusions. Fourth, based of the complex conclusions come up with a theory that covers all possible situations related to that problem.

WUP 01: Describe, in your own words, the four principal rules of Descartes’ method of rightly conducting one's

reason and of seeking truth in the sciences.

• science rules! descartes thought he knew everything

• Tjfrifdhjj: Not sure

• Happy Gilmore: 1. Accept as true only what has no doubts. 2. Break each question into manageable parts. 3. Start with the easiest issues, and work towards the more difficult ones. 4. Occasionally review topic, to be able to retain the whole argument at once.

• TK 1) to never believe anything unless he can prove it himself 2) to reduce every problem to its simplest parts 3) to always be orderly in his thoughts and proceed from the simplest part to the most difficult 4) to always, when solving a problem, create a long chain of reasoning and leave nothing out

A Classical Example

• Aristotle observes that during lunar eclipses the Earth’s shadow on the moon is curved

• He assumes it will be curved for all eclipses• A hypothesis that explains this: the earth is a sphere• A prediction of this theory is that the location of the

stars in the sky should be different for observers at different latitudes

• This is confirmed by additional observations– E.g. Canopus is visible in Egypt but not further north

• It is applied by Eratosthenes to determine the size of Earth

HOMEWORK QUESTIONS?