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What is “Inquiry in the Natural World”?

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Presentation on theme: "What is “Inquiry in the Natural World”?"— Presentation transcript:

1 What is “Inquiry in the Natural World”?
Clare Inquiry in the Natural World Ted Georgian 19 January 2005

2 Natty-world is a great course - really!
This course isn’t as hard as you’ve heard. To do well: 1. Attend ALL lectures and small classes 2. Use the learning objectives (demonstrate) 3. Ask for help - early

3 Two simple questions: What is the “natural world”?
What does it mean to “inquire” about it?

4 What is the “natural world”?
A collection of physical objects – but, a staggering diversity of numbers and types

5 What’s a “physical object”?
Physical objects appear as consistent “packages” with: 1. measurable properties 2. philosophers, theologians, scientists don’t agree as to whether this is ALL that exists

6 Is “love” a physical object”?
But the NATURAL SCIENCES (physics, chemistry, and biology) study only physical objects that are observable and measurable: 1. Could study their hormone levels or EEGs 2. But not the idea of love

7 Are there physical objects that we can’t sense?
Dogs know who’s been at the fire hydrant

8 Are there physical object that we can’t sense?
Do Honey bees see objects that we can’t? Medical and Scientific Photography: An online resource for doctors, scientists and students (http://msp.rmit.edu.au/Article_01/13.html)

9 Are there physical objects that we can’t sense?
Modern instruments have greatly extended our detection abilities Science leads to technological progress, but technology also encourages scientific progress - Microscopes: 1600s; lead to the discovery of MICROORGANISMS and great progress in fighting disease - Telescopes: also 1600s; showed us the nature of the universe – but ~90% of the universe may be “dark matter” which we can’t detect

10 Can we make predictions about the natural world?
Given a knowledge of the “laws” of physics, can you predict where this car will go if you release the parking brake? A car is a MACHINE – doesn’t decide whether or not to roll down hill.

11 Can we make predictions about the natural world?
Given the same knowledge of the “laws” of physics, can you predict where a car will go if it’s hijacked by a 14-year old? But a human does make decisions: - some scientists believe we will eventually understand neurobiology, psychology, & sociology so well that human behavior will be completely predictable - others believe that human freedom of choice is absolute and can never be completely predictable

12 What’s “inquiry” in the natural world?

13 Scientists ask a lot of questions, like kids
Some common questions kids ask: Why is the sky blue? Where do babies come from? Why does the moon follow my car? And my favorite: How can a brown cow eat green grass and make white milk? My parents couldn’t answer my question about the moon (most adults can’t). A quick answer is that it’s caused by something called “parallax” that we’ll study later this semester Most kids, sadly, stop asking questions pretty quickly: - trained to accept home.att.net/~rwskinner/ pictures/brown-cow-2.jpg

14 Two different sorts of answers
1. Descriptions “The sky is dark blue.” Explanations “The sky is blue because …” sky_blue.html

15 Why inquire into the natural world?
Two fundamental reasons: Curiosity Problem solving

16 Curiosity-driven science
Basic or “pure” Often leads to surprisingly practical discoveries Teflon Lasers DNA Serena Parente Charlebois Flubber (?) X-rays

17 Problem-solving science
Applied or “practical” Gives us substantial power over the natural world Contraceptives Weapons Transgenic crops Internal combustion engines Computers

18 Problem-solving science

19 Why do physical objects behave the way they do?
Anthropomorphic explanation

20 Why do physical objects behave the way they do?
Mechanistic explanation

21 A complex and very general explanation is often called a “Model”
Isaac Newton’s model of “Universal Gravitation” darwin.apnet.com/ www/ap/newton.htm Isaac%20Newton.jpg

22 Newton’s model of “Universal Gravitation” has been very successful
Craft launched to dive into comet By MARCIA DUNN Associated Press 1/13/2005 CAPE CANAVERAL, Fla. - A NASA spacecraft with a Hollywood name - Deep Impact - blasted off Wednesday on a mission to smash a hole in a comet and give scientists a glimpse of the frozen primordial ingredients of the solar system. With a launch window only one second long, Deep Impact rocketed away at the designated moment on a six-month, 268 million-mile journey to comet Tempel 1. It will be a one-way trip that NASA hopes will reach a cataclysmic end on the Fourth of July. Nothing like this has ever been attempted before. Little is known about comet Tempel 1, other than that it is an icy, rocky body about nine miles long and three miles wide. Buffalo News, 13 Jan 2005, A8

23 How do we investigate physical objects?
jkostaras/big_ben.jpg perl.plover.com/yak/ regex/samples/slide004.html

24 What are physical objects made of?
Here’s one early idea – “atomism” (Leucippus and Democritus, ~ 500 BC) Trefil, J. & R. M. Hazen. The Sciences. 2nd ed. P. 163

25 What are physical objects made of?
Here’s an alternate view – “elementalism” Aristotle (384 – 322 BC)

26 Aristotle’s “model” of physical objects
Here’s how it worked:

27 Aristotle’s “model” was widely accepted as “true” from ~ 300 B. C
Aristotle’s “model” was widely accepted as “true” from ~ 300 B.C. until ~ 1700s

28 Atomism was revived in the 1800s
John Dalton, 1808. A New System of Chemistry

29 How do scientists decide which explanations are best?
Democritus Aristotle

30 The “hypothetico-deductive” scientific method
More of a description of what usually works than a set of directions that every scientist follows Still – no better way of investigating the natural world has been invented in the past 400 years

31 Francis Bacon ( ) Stressed observation over philosophical speculation Proposed a new method of studying nature Argued that if we understand nature we can dominate it

32 Steps in the scientific method
Step 1: Observations

33 Steps in the scientific method
Step 1 a: decide what to study Too much Better

34 Steps in the scientific method
In western New York, cars in winter!

35 How can we answer our questions about the natural world?
Step 1b: look for a general pattern This step uses a process called Inductive Reasoning in which we develop a rule based on many individual examples

36 Steps in the scientific method
Step 1b: look for a general pattern

37 How can we answer our questions about the natural world?
Step 2: Think up explanations (hypotheses) for the patterns observed A useful hypothesis:

38 Steps in the scientific method
Step 2: Think up explanations (hypotheses) for the patterns observed 1. Car won’t start because the coolant is frozen solid. 2. Car won’t start because the battery is too weak. 3. Car won’t start because it wants to be in Florida and it’s sulking. 4. Car won’t start because snow banks are actually alien spaceships and the aliens have ray guns that disable cars.

39 Ockham’s “Razor” Start with the simplest possible explanation and go to more complex explanations only if the simpler explanations don’t work. William of Ockham (1280 – 1347)

40 But the natural world isn’t necessarily simple!
“Make everything as simple as possible, but not simpler."   --  Albert Einstein ( ) sprott.physics.wisc.edu/ images/einstein.jpg

41 Steps in the scientific method
These two seem like reasonable hypotheses: Car won’t start because the coolant is frozen solid. Car won’t start because the battery is too weak. How can we tell which hypothesis is a better explanation of our observations?

42 How can we answer our questions about the natural world?
Step 3: Make a testable prediction This step uses a process called Deductive reasoning in which we use the rules of logic to generate a prediction

43 Steps in the scientific method
Step 3: Make a testable prediction IF the trouble starting the car is caused by the coolant being frozen, THEN we should see ice when we open the radiator cap.

44 Steps in the scientific method
Step 4: Make observations or do experiments to test our explanations A good experiment:

45 Steps in the scientific method
Step 4: Make observations or do experiments to test our explanations Observation: open the radiator cap and look. Result: antifreeze is fine – not frozen. Now what???

46 Start over again!

47 Steps in the scientific method
Step 3: Make a testable prediction IF the trouble starting the car is caused by the battery being weaker at low temperatures, THEN replacing the battery should enable the car to start on cold mornings

48 Steps in the scientific method
Step 4: Make observations or do experiments to test our explanations Observations: use a voltmeter to test the battery each time the car won’t start Experiment: try a new battery

49 Good experiments have:
Controls Need 2+ identical cars Experimental car: remove old battery and install a new one. Control car: remove old battery and reinstall it. Replication The experiment needs to be repeated by other people on many other cars before we can be sure it’s generally reliable.

50 How can we test Aristotle’s model?
Aristotle (384 – 322 BC)

51 What predictions does it make?
According to Aristotle, each element has a natural resting place, and will return to it D. Park The How and the Why: An essay on the origins and development of physical theory. Princeton University Press, p. 49

52 Here’s an example What’s mud made of?

53 Here’s another example
What happens when wood burns? Observations: at first bubbling liquid comes out of the end of the wood, then yellowish flames leap up, releasing light and heat. When the fire goes out, gray ash remains at the bottom of the fireplace. The ash helps plants grow in the garden.

54 What happens when wood burns?
Explanation: wood is a mixture of mainly Earth and Fire, with varying amounts of Air and Water. When wood burns, the Fire escapes as flames and rises to its natural resting place, leaving behind ash, which is mostly Earth and so nourishes plants.

55 How can we decide if this model is a good scientific explanation?
Let’s not burn down Murphy Hall Pick an easier object to study: water Do experiments rather than just observe

56 What does Aristotle’s model predict?
If the electric current heats the Water, it should produce “Air” The resulting Air should rise Pure Water should produce only one type of Air

57 Here’s what the experiment looks like

58 What actually happens? Results: “Air” from one tube floats, one sinks
One is flammable, one isn’t Conclusion: two different types of Air were produced

59 What do we do now? "The great tragedy of Science—the slaying of a beautiful hypothesis by an ugly fact." Thomas Huxley Give up and go to work at McDonalds Modify the hypothesis Develop a better explanation of the nature of matter

60 Here’s another model of water
The mechanical model of the 1800s

61 So: is this the right answer?
Not since ~1900! Stay tuned for details later.

62 How does science make progress?
Occurs in cycles Gradually eliminates poor explanations, but ... The process is never complete. M. Johnson Human Biology. 2nd ed. Benjamin Cummings.


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