a history of the scientific method thales of miletus (a small town originally on the coast of...

A History of the Scientific Method

Thales of Miletus (a small town originally on the coast of Turkey)

Pythagoras and Mathematics

c

a

b

a2 + b2 = c2

Plato and Knowledge

The universe is knowable--it just takes logic.

Roger Bacon and Empiricism

Observations tell us how nature works.

Rene Descartes and Rationalism

Intellect is enough to tell us how things work.

Not THIS Francis Bacon . . .

Sir Francis Bacon andthe Scientific Method

•People serve and interpret nature

•Truth is not derived from authority

•Knowledge is the fruit of experience

The Scientific Method Recognize what the question or problem actually

is Make an educated guess (aka “hypothesis”) as to

what’s causing it Predict further consequences of your hypothesis Perform experiments testing your predictions Formulate a rule governing what you see Repeat as necessary

Examples of “Bad Science” Intransigence in the face of compelling

evidence Not having a test for falseness (or

wrongness, if you prefer) “Fudging” data (equivalent to lying)

??

Mathematics & Science

Admittedly, mathematics can be a bit like a foreign language, but at least there are no “exception to the rule” problems. But nothing can so briefly state a scientific theory as an equation.

F=ma(“Force = mass times acceleration”, but really it’s a lot more than that!)

The Scientific Method vs. “Bad” Science as Applied to Air Resistance

Aristotle said that the rate at which objects fall depends upon their mass.

Galileo said that all objects fall at a constant rate of acceleration (9.8 m/s2 = 32 ft/s2).

My casual observations suggest that neither of these is correct.

Bad Science says . . .

It’s air resistance, Bonehead! Duhhhh! Let’s go to the next problem, in which we show that black is white and white is black and Bill Gates is the Anti-Christ . . . .

Good Science Says . . .

We seem to have a problem in that objects fall at different rates. Mass has an effect, but it’s not the only effect. Our hypothesis is that it is due to resistance from the air through which the object is falling.

Let’s make some predictions based upon our hypothesis: Greater cross-sectional area should lead to

greater effects from air resistance For two objects of equal cross-sectional

area, the heavier one falls at a greater rate of acceleration

The faster an object falls, the greater the air resistance

In a vacuum, all objects fall at equal rates

We now must test our predictions

Drop two objects of equal mass but different cross-sectional area

Drop two objects of equal cross-sectional area but different mass

Drop an object from a great height and see if it eventually stops accelerating

Create a vacuum and drop two very different objects

Bad Science says:

You just saw it happen. Why do you run that experiment again and again?

Nah, I don’t think that humidity or altitude would affect anything. We’ve covered it all.

We have our numbers. They’re precise enough.

Our hypothesis seems correct, but that doesn’t mean it’s complete: If the cross sectional area doubles/triples, does

the air resistance double/triple? A cube and a sphere can have the same cross

sectional area. Do they fall the same? Does the air resistance increase proportionally

with velocity? Does it increase faster? Slower?

What about resistance by gases other than air?