Exploring Theories and Laws

How are these four concepts related to each other? Theories Laws How are these four concepts related to each other? Facts Hypotheses

Common Descriptions Facts are indisputable, proven, known to have happened Hypotheses are educated guesses, hunches, unsubstantiated claims Theories are unsubstantiated ideas, opinions, unproven explanations Laws are proven theories that have withstood repeated testing over time, rules that must be followed, a piece of enacted legislation After they have talked about it move onto this slide

L A W (fact) THEORY HYPOTHESIS When proven that it always works When supported over time Only call on those with misconceptions Is this consistent with what Helen Curtis said? The rest of what we will be doing is exploring the validity of this Be to here in 10mins tops HYPOTHESIS

From Where Do These Ideas Originate?

Theories in Media

Laws in Media

Explicit Instruction Answer: A law is something that can be measured or observed to be true. A theory is something that can only be assumed to be true based on the best available knowledge. A theory can eventually, though not necessarily, become a law after time and scrutiny.

Student & Teacher Ideas A scientific law is a theory that has been proven over and over by different scientists. A scientific law is definite, and nothing is named a law unless scientists agree that there is no question to its being true. For example, scientists are open to finding new information about the atomic theory, but Newton’s law of motion has been tested enough times that scientists are certain it is true. Newton’s 1st Law is proven and through various testing and experiments it has come to be known as a proven law. Theories, however, have not been proved enough to be changed into laws.

Jigsaw Activity Read your article. Discuss the authors’ definitions and examples of scientific fact, theory, law, and hypothesis. How are these similar/different from the commonly used/Helen Curtis’ definitions of these terms? Be prepared to briefly share with the class.

List examples of scientific theories and laws…. Theories Laws

Theories Laws Theory of Special Relativity: The speed of light in a vacuum is constant regardless of the motion of the observer or the motion of the light source. Explains the relationship between mass and energy. Newton’s Laws of Motion: Describes the relationship between the forces acting on a body and its motion due to those forces. Atomic Theory: All matter is composed of elements made up of atoms. Explains why matter is conserved in chemical reactions. Ideal Gas Law: PV=nRT Describes the relationship between pressure, volume, moles, and temperature of a gas. Electromagnetic Field Theory: A change in an electric field produces a perpendicular magnetic field. A change in a electric field produces a perpendicular electric field. Explains the way in which charges and currents interact. Ohm’s Law: V = IR Describes the relationship between the voltage (V), current (I), and resistance (R). Theory of Plate Tectonics: Earth’s crust is divided into plates that move. Explains why earthquakes and volcanoes occur in certain zones. Law of Superposition: Describes the general principle that in undeformed layers of rock, the oldest rock will be at the bottom.

Theories Laws Theory of Special Relativity: The speed of light in a vacuum is constant regardless of the motion of the observer or the motion of the light source. Explains the relationship between mass and energy. Newton’s Laws of Motion: Describes the relationship between the forces acting on a body and its motion due to those forces. Atomic Theory: All matter is composed of elements made up of atoms. Explains why matter is conserved in chemical reactions. Ideal Gas Law: PV=nRT Describes the relationship between pressure, volume, moles, and temperature of a gas. Electromagnetic Field Theory: A change in an electric field produces a perpendicular magnetic field. A change in a electric field produces a perpendicular electric field. Explains the way in which charges and currents interact. Ohm’s Law: V = IR Describes the relationship between the voltage (V), current (I), and resistance (R). Theory of Plate Tectonics: Earth’s crust is divided into plates that move. Explains why earthquakes and volcanoes occur in certain zones. Law of Superposition: Describes the general principle that in undeformed layers of rock, the oldest rock will be at the bottom.

Theories Explain Observations Theory of Plate Tectonics: Earth’s crust is divided into plates that move. Explains why earthquakes and volcanoes occur in certain zones. Electromagnetic Field Theory: A change in an electric field produces a perpendicular magnetic field. A change in a magnetic field produces a perpendicular electric field. Explains the way in which charges and currents interact. Darwin’s theory of natural selection: Explains the diversity of life in terms of competition, survival, and inherited traits. Explains the fossil record and how species can change over time. Atomic Theory: Matter is composed of discrete units called atoms, as opposed to the obsolete notion that matter could be divided into any arbitrarily small quantity Explains why matter is conserved in chemical reactions.

Theories Explain Laws Einstein’s General Theory of Relativity: Explains gravity in terms of space-time curvature and that space-time is curved by matter. Law of universal gravitation: Describes the relationship between mass, distance, and the force of gravity. Chromosome Theory: chromosomes are the basis for all genetic inheritance. Explains the mechanism underlying Mendel’s laws. The law of independent assortment: Describes the principle that traits are passed on to offspring independent of each other . Kinetic Molecular Theory: Matter consists of tiny particles in constant motion, whose speed is proportional to the absolute temperature. Explains gas laws. Boyle’s Law: Describes the relationship between pressure and volume of a gas when temperature is held constant. it took less than a decade for researchers to start to identify some serious limitations to the patterns of inheritance seen by Mendel. Some of these will be familiar to anyone with a high school biology education: incomplete dominance, environmental influences, and so forth. But the basic insight Mendel had—that genes were more or less invariant across generations, even if the traits they promoted would sometimes be impossible to detect—could be used to explain all of these exceptions. The other major exception is imprinting, where the DNA is chemically modified, sometimes in response to environmental cues, and the modification can be retained across generations. This epigenetic inheritance is pretty rare, although there are some human diseases that are caused by improper imprinting. Works only for diploid organisms—many plants are haploid or even polyploid. Male animals are haploid for sex-linked traits.

Which Came First? General Theory of Relativity: Law of Universal Gravitation: Chromosome Theory: Law of Independent Assortment: Kinetic Molecular Theory: Boyle’s Law: it took less than a decade for researchers to start to identify some serious limitations to the patterns of inheritance seen by Mendel. Some of these will be familiar to anyone with a high school biology education: incomplete dominance, environmental influences, and so forth. But the basic insight Mendel had—that genes were more or less invariant across generations, even if the traits they promoted would sometimes be impossible to detect—could be used to explain all of these exceptions. The other major exception is imprinting, where the DNA is chemically modified, sometimes in response to environmental cues, and the modification can be retained across generations. This epigenetic inheritance is pretty rare, although there are some human diseases that are caused by improper imprinting. Works only for diploid organisms—many plants are haploid or even polyploid. Male animals are haploid for sex-linked traits.

Which Came First? General Theory of Relativity: Einstein: 1916 Law of Universal Gravitation: Newton: 1687 Kinetic Molecular Theory: Bernoulli, Clausius: 1738, 1857 Boyle’s Law: Boyle: 1662 Chromosome Theory: Thomas Hunt: 1910 Law of Independent Assortment: Mendel: 1866 it took less than a decade for researchers to start to identify some serious limitations to the patterns of inheritance seen by Mendel. Some of these will be familiar to anyone with a high school biology education: incomplete dominance, environmental influences, and so forth. But the basic insight Mendel had—that genes were more or less invariant across generations, even if the traits they promoted would sometimes be impossible to detect—could be used to explain all of these exceptions. The other major exception is imprinting, where the DNA is chemically modified, sometimes in response to environmental cues, and the modification can be retained across generations. This epigenetic inheritance is pretty rare, although there are some human diseases that are caused by improper imprinting. Works only for diploid organisms—many plants are haploid or even polyploid. Male animals are haploid for sex-linked traits.

Boyle’s Law New Experiments Physico-Mechanicall, Touching the Spring of the Air, and its Effects... (1662) http://www.chemteam.info/GasLaw/Gas-Boyle-Data.html Image Retrieved from: http://web.lemoyne.edu/~giunta/gaygas.html Image Retrieved from: http://www.leeds.ac.uk/library/adopt-a-book/boyle.htm 7 investigations deal with changes in pressure as a result of changes in volume

Boyle’s Law: 1662 Data Image Retrieved from: http://web.lemoyne.edu/~giunta/gaygas.html Graph Image retrieved from: http://www.mentorials.com/high-school-chemistry-matter-properties-of-gases-and-gas-laws.htm

Kinetic Molecular Theory (Early Ideas about Molecular Motion) Bernoulli (1738): Hydrodynamica Gases consist of great numbers of molecules moving in all directions Impact on a surface causes gas pressure Heat is the kinetic energy of their motion Herapath (1821): Gas particle momentum is a measure of the absolute temperature of the gas Waterston (1843): Gas pressure is a function of the number of molecules per unit volume, molecular mass, and molecular mean-squared velocity Note: both Herapath and Waterston initially failed peer review when attempting to get their ideas published by the Royal Society of London http://web.lemoyne.edu/~giunta/herapath.html http://www-users.math.umd.edu/~lvrmr/History/EarlyTheories.html http://en.wikipedia.org/wiki/John_James_Waterston http://web.lemoyne.edu/~giunta/CLAUSIUS57.html

Kinetic Molecular Theory Clausius (1857) Included translational, rotational, and vibrational particle motion The size of a particle is negligibly small relative to its container The duration of impact is infinitesimal as compared to the time between two successive collisions. Others continued working on theory for the next 50 years: Maxwell (1859) Boltzmann (1890s) Einstein (1905) and Smoluchowski (1906) Brownian motion

Timeline of Gas Laws and KMT 1662 1738 1857 Boyle’s Law Bernoulli (initial ideas about particle motion) Clausius first “complete” version of Kinetic Molecular Theory

Scientific Hypothesis: Scientific Fact: “In science ‘fact’ can only mean ‘confirmed to such a degree that it would be perverse to withhold provisional consent’.” Stephen J. Gould Scientific Hypothesis: A proposed answer to a research question A tentative explanation for an observation or phenomena that can be tested through experimentation. Now we are going to look at the relationship

Scientific Theory: Scientific Law: A general principle supported by a substantial body of evidence offered to provide an explanation of observed facts and as a basis for future discussion or investigation. Lincoln, Boxshall, and Clark (1990) Scientific Law: A scientific law is a description of a natural relationship or principle, often expressed in mathematical terms.

Is there a hierarchy among the four original concepts? Facts Theories Laws Hypotheses

Laws Theories Hypotheses Facts More absolute And, eventually proven, become Theories Less absolute Which, when supported by experiments, become Hypotheses Lead scientists to develop Facts

Laws Theories Hypotheses Facts More absolute And, eventually proven, become Theories Less absolute Which, when supported by experiments, become Hypotheses Lead scientists to develop Facts

THEORY L A W HYPOTHESIS

THEORY L A W HYPOTHESIS Explanatory principal Based more on inference Concise, descriptive principal Based more on observation HYPOTHESIS

? So How Do We Teach This? Mystery Tube Law of Strings String Theory When any short string is pulled, the long string shortens by an equivalent amount. String Theory ? Activity to teach to you students Demo the mystery tube – predictions and observations Ask whether anyone can make a generalization about what is happening? When the short one is pulled the long one goes in. Law of the Strings. “Our next goal is to come up with String Theory” Have them start drawing on the templates in groups at their table. Make inferences in groups – have tubes scattered around the room and templates Have groups share their ideas – Circulate around the room to find ppl with different drawings 30

So How Do We Teach This? Mystery Tube Activity to teach to you students Demo the mystery tube – predictions and observations Ask whether anyone can make a generalization about what is happening? When the short one is pulled the long one goes in. Law of the Strings. “Our next goal is to come up with String Theory” Have them start drawing on the templates in groups at their table. Make inferences in groups – have tubes scattered around the room and templates Have groups share their ideas – Circulate around the room to find ppl with different drawings 31

Post-Instruction Quotes from Students & Teachers Scientific theories never turn into laws. A scientific law is often mathematical and is used to describe a pattern found in nature. A theory is used to try and explain the ‘why’ of a pattern or occurrence. A scientific law is a statement describing how something works. A scientific theory attempts to explain something that cannot be directly observed. Laws are usually something that is observable. Theories are based on inference, an effort to explain something.

Laws and Theories Laws Theories Based primarily on observations Based on evidence Can change with new evidence Cannot change into each other Based primarily on observations Holds for specific conditions More descriptive Answers “what happens?” Relies heavily on inferences Generalizations More explanatory Answers “How does it happen?” Closure Slide Laws: Primarily based on Observations Typically holds only under specific conditions More Descriptive “what” Theories: Based on Inferences Generalizations More Explanatory “why” Similarities: Based on lots of evidence Can change when new evidence is discovered These are 2 different types of scientific knowledge, they cannot change into each other