Presentation on theme: "What is “Inquiry in the Natural World”?"— Presentation transcript:
1What is “Inquiry in the Natural World”? Clare Inquiry in the Natural WorldTed Georgian19 January 2005
2Natty-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 classes2. Use the learning objectives (demonstrate)3. Ask for help - early
3Two simple questions: What is the “natural world”? What does it mean to “inquire” about it?
4What is the “natural world”? A collection of physical objects – but, a staggering diversity of numbers and types
5What’s a “physical object”? Physical objects appear as consistent “packages” with:1. measurable properties2. philosophers, theologians, scientists don’t agree as to whether this is ALL that exists
6Is “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 EEGs2. But not the idea of love
7Are there physical objects that we can’t sense? Dogs know who’s been at the fire hydrant
8Are 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)
9Are there physical objects that we can’t sense? Modern instruments have greatly extended our detection abilitiesScience 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
10Can 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.
11Can 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
13Scientists 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 semesterMost kids, sadly, stop asking questions pretty quickly:- trained to accepthome.att.net/~rwskinner/ pictures/brown-cow-2.jpg
14Two different sorts of answers 1. Descriptions “The sky is dark blue.”Explanations “The sky is blue because …”sky_blue.html
15Why inquire into the natural world? Two fundamental reasons:CuriosityProblem solving
16Curiosity-driven science Basic or “pure”Often leads to surprisingly practical discoveriesTeflonLasersDNASerena Parente CharleboisFlubber (?)X-rays
17Problem-solving science Applied or “practical”Gives us substantial power over the natural worldContraceptivesWeaponsTransgenic cropsInternal combustion enginesComputers
19Why do physical objects behave the way they do? Anthropomorphic explanation
20Why do physical objects behave the way they do? Mechanistic explanation
21A complex and very general explanation is often called a “Model” Isaac Newton’s model of “Universal Gravitation”darwin.apnet.com/ www/ap/newton.htmIsaac%20Newton.jpg
22Newton’s model of “Universal Gravitation” has been very successful Craft launched to dive into comet By MARCIA DUNN Associated Press 1/13/2005CAPE 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
23How do we investigate physical objects? jkostaras/big_ben.jpgperl.plover.com/yak/ regex/samples/slide004.html
24What 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
25What are physical objects made of? Here’s an alternate view – “elementalism”Aristotle (384 – 322 BC)
26Aristotle’s “model” of physical objects Here’s how it worked:
27Aristotle’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
28Atomism was revived in the 1800s John Dalton, 1808.A New System of Chemistry
29How do scientists decide which explanations are best? DemocritusAristotle
30The “hypothetico-deductive” scientific method More of a description of what usually works than a set of directions that every scientist followsStill – no better way of investigating the natural world has been invented in the past 400 years
31Francis Bacon ( )Stressed observation over philosophical speculationProposed a new method of studying natureArgued that if we understand nature we can dominate it
32Steps in the scientific method Step 1: Observations
33Steps in the scientific method Step 1 a: decide what to studyToo muchBetter
34Steps in the scientific method In western New York, cars in winter!
35How can we answer our questions about the natural world? Step 1b: look for a general patternThis step uses a process called Inductive Reasoningin which we develop a rule based on many individual examples
36Steps in the scientific method Step 1b: look for a general pattern
37How can we answer our questions about the natural world? Step 2: Think up explanations (hypotheses) for the patterns observedA useful hypothesis:
38Steps in the scientific method Step 2: Think up explanations (hypotheses) for the patterns observed1. 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.
39Ockham’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)
40But 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
41Steps 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?
42How can we answer our questions about the natural world? Step 3: Make a testable predictionThis step uses a process called Deductive reasoningin which we use the rules of logicto generate a prediction
43Steps in the scientific method Step 3: Make a testable predictionIF the trouble starting the car is caused by the coolant being frozen,THEN we should see ice when we open the radiator cap.
44Steps in the scientific method Step 4: Make observations or do experiments to test our explanationsA good experiment:
45Steps in the scientific method Step 4: Make observations or do experiments to test our explanationsObservation: open the radiator cap and look. Result: antifreeze is fine – not frozen.Now what???
47Steps in the scientific method Step 3: Make a testable predictionIF 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
48Steps in the scientific method Step 4: Make observations or do experiments to test our explanationsObservations: use a voltmeter to test the battery each time the car won’t start Experiment: try a new battery
49Good experiments have: ControlsNeed 2+ identical carsExperimental 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.
50How can we test Aristotle’s model? Aristotle (384 – 322 BC)
51What predictions does it make? According to Aristotle, each element has a natural resting place, and will return to itD. Park The How and the Why: An essay on the origins and development of physical theory. Princeton University Press, p. 49
53Here’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.
54What 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.
55How can we decide if this model is a good scientific explanation? Let’s not burn down Murphy HallPick an easier object to study: waterDo experiments rather than just observe
56What does Aristotle’s model predict? If the electric current heats the Water, it should produce “Air”The resulting Air should risePure Water should produce only one type of Air
58What actually happens? Results: “Air” from one tube floats, one sinks One is flammable, one isn’tConclusion: two different types of Air were produced
59What do we do now?"The great tragedy of Science—the slaying of a beautiful hypothesis by an ugly fact." Thomas HuxleyGive up and go to work at McDonaldsModify the hypothesisDevelop a better explanation of the nature of matter
60Here’s another model of water The mechanical model of the 1800s
61So: is this the right answer? Not since ~1900! Stay tuned for details later.
62How does science make progress? Occurs in cyclesGradually eliminates poor explanations, but ...The process is never complete.M. Johnson Human Biology. 2nd ed. Benjamin Cummings.