Presentation on theme: "What is “Inquiry in the Natural World”? Clare 102 - Inquiry in the Natural World Ted Georgian 19 January 2005."— Presentation transcript:
What is “Inquiry in the Natural World”? Clare 102 - Inquiry in the Natural World Ted Georgian 19 January 2005
Natty-world is a great course - really!
Two simple questions: 1.What is the “natural world”? 2.What does it mean to “inquire” about it?
What is the “natural world”? http://www.howardhallis.com/artgallery/tpoe/index.html
What’s a “physical object”? http://the.honoluluadvertiser.com/article/200 2/Dec/10/ln/ln12a.html
Is “love” a physical object”?
Are there physical objects that we can’t sense? Dogs know who’s been at the fire hydrant
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)
Are there physical objects that we can’t sense? Modern instruments have greatly extended our detection abilities
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?
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?
What’s “inquiry” in the natural world?
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? home.att.net/~rwskinner/ pictures/brown-cow-2.jpg
Two different sorts of answers 1. Descriptions “The sky is dark blue.” 2. Explanations “The sky is blue because …” http://www.albforumi.com/cgi- bin/ultimatebb.cgi?ubb=get_t opic;f=16;t=000024;p= www.sciencemadesimple.com/ sky_blue.html
Why inquire into the natural world? Two fundamental reasons: Curiosity Problem solving
Curiosity-driven science Serena Parente Charlebois Basic or “pure” Often leads to surprisingly practical discoveries Lasers X-rays Teflon DNA Flubber (?)
Problem-solving science Applied or “practical” Gives us substantial power over the natural world Weapons Computers Contraceptives Transgenic crops Internal combustion engines
Why do physical objects behave the way they do? Anthropomorphic explanation
Why do physical objects behave the way they do? Mechanistic explanation
A complex and very general explanation is often called a “Model” http://www.metaresearch.org/cosmology/cosmology.asp www.prometheus-delft.org/ Isaac%20Newton.jpg Isaac Newton’s model of “Universal Gravitation” darwin.apnet.com/ www/ap/newton.htm
Newton’s model of “Universal Gravitation” has been very successful Buffalo News, 13 Jan 2005, A8 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. Craft launched to dive into comet By MARCIA DUNN Associated Press 1/13/2005
How do we investigate physical objects? perl.plover.com/yak/ regex/samples/slide004.html www.geocities.com/ jkostaras/big_ben.jpg
What are physical objects made of? Here’s one early idea – “atomism” (Leucippus and Democritus, ~ 500 BC) Trefil, J. & R. M. Hazen. The Sciences. 2 nd ed. P. 163
What are physical objects made of? Here’s an alternate view – “elementalism” http://astsun.astro.virginia.edu/~jh8h/Foundations/c hapter2.html Aristotle (384 – 322 BC)
Aristotle’s “model” of physical objects Here’s how it worked: http://www.chem.uidaho.edu/~honors/history.html
Aristotle’s “model” was widely accepted as “true” from ~ 300 B.C. until ~ 1700s
Atomism was revived in the 1800s John Dalton, 1808. A New System of Chemistry
How do scientists decide which explanations are best? Democritus Aristotle
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
Francis Bacon (1561-1626) Stressed observation over philosophical speculation Proposed a new method of studying nature Argued that if we understand nature we can dominate it
Steps in the scientific method Step 1: Observations
Steps in the scientific method Step 1 a: decide what to study Too much Better http://svdp.org/santaclara/images/Car_Lot.jpg
Steps in the scientific method In western New York, cars in winter! http://www.bigfoto.com/themes/nature/winter/ http://www.heatherandpatrick.com/Kitten-Library/details.php?photoID=194 http://www.budinas.narod.ru/current/winter4/winter4e.htm
How can we answer our questions about the natural world? This step uses a process called Inductive Reasoning This step uses a process called Inductive Reasoning in which we develop a rule based on many individual examples Step 1b: look for a general pattern
Steps in the scientific method Step 1b: look for a general pattern http://emd.wa.gov/5-ppt/trng/pubed/winterprep/starting-car-cold.htm
How can we answer our questions about the natural world? A useful hypothesis: 1. 1. 2. 2. 3. 3. Step 2: Think up explanations (hypotheses) for the patterns observed
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.
Ockham’s “Razor” Start with the simplest possible explanation and go to more complex explanations only if the simpler explanations don’t work. 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)
But the natural world isn’t necessarily simple! “Make everything as simple as possible, but not simpler." -- Albert Einstein (1879-1955) sprott.physics.wisc.edu/ images/einstein.jpg
Steps in the scientific method How can we tell which hypothesis is a better explanation of our observations? 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 answer our questions about the natural world? This step uses a process called Deductive reasoning in which we use the rules of logic to generate a prediction Step 3: Make a testable prediction
Steps in the scientific method IF the trouble starting the car is caused by the coolant being frozen, Step 3: Make a testable prediction THEN we should see ice when we open the radiator cap.
Steps in the scientific method A good experiment: 1. 2. 3. 1. 2. 3. Step 4: Make observations or do experiments to test our explanations
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???
Start over over again! again!
Steps in the scientific method IF the trouble starting the car is caused by the battery being weaker at low temperatures, Step 3: Make a testable prediction THEN replacing the battery should enable the car to start on cold mornings
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
Good experiments have: Replication The experiment needs to be repeated by other people on many other cars before we can be sure it’s generally reliable. Controls Need 2+ identical cars Need 2+ identical cars Experimental car: remove old battery and install a new one. Control car: remove old battery and reinstall it.
How can we test Aristotle’s model? http://www.chem.uidaho.edu/~honors/history.html Aristotle (384 – 322 BC)
What predictions does it make? D. Park. 1988. The How and the Why: An essay on the origins and development of physical theory. Princeton University Press, p. 49 According to Aristotle, each element has a natural resting place, and will return to it
Here’s an example What’s mud made of?
Here’s another example 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. 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.
How can we decide if this model is a good scientific explanation? 1. Let’s not burn down Murphy Hall 2. Pick an easier object to study: water 3. Do experiments rather than just observe
What does Aristotle’s model predict? 1. If the electric current heats the Water, it should produce “Air” 2. The resulting Air should rise 3. Pure Water should produce only one type of Air
Here’s what the experiment looks like
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
What do we do now? 1. Give up and go to work at McDonalds "The great tragedy of Science— the slaying of a beautiful hypothesis by an ugly fact." Thomas Huxley 2. Modify the hypothesis 3.Develop a better explanation of the nature of matter
Here’s another model of water The mechanical model of the 1800s
So: is this the right answer? Not since ~1900! Stay tuned for details later.
How does science make progress? 1. Occurs in cycles 2. Gradually eliminates poor explanations, but... 3. The process is never complete. M. Johnson. 2003. Human Biology. 2 nd ed. Benjamin Cummings.