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Big Idea 3 _ The Role of Theories_ Laws_ Hypotheses_ and Models

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Big Idea 3 _ The Role of Theories_ Laws_ Hypotheses_ and Models Powered By Docstoc
					                        Description
The terms that describe examples of
 scientific knowledge, (e.g. "theory,"
    "law," "hypothesis," and "model“)
     have very specific meanings and
             functions within science.
Benchmark Number
   & Descriptor
 SC.7.N.3.1
 Recognize and explain the difference
  between theories and laws, and give
  several examples of scientific theories
  and the evidence that supports them.
 SC.7.N.3.2
 Identify the benefits and limitations of
  the use of scientific models.
  SCIENTIFIC THEORY
 A scientific          Theories may be
  explanation to a      supported by
  pattern in the        scientific evidence
  natural world         at the time but may
 Many observations     be incorrect.
  and much evidence       Evidence may
  is needed in order       change with time;
  to create a valid        better technology
  theory.                 Example:
                           Geocentric (earth
 Scientific
                           in middle of solar
  investigation is a       system) to
  key part when            Heliocentric
  creating theories.       model (sun in
                           middle of solar
                           system)
    EXAMPLES of
SCIENTIFIC THEORIES
 Big Bang Theory          Theory of Matter
   The universe has       and Energy
    expanded from hot,       Matter and Energy
    dense, gaseous            are always
    conditions.               conserved.
 Tectonic Plate           Cell Theory
  Theory                     Cells form the
   The surface of the        foundation, the
    earth is composed         basic unit of all
    of tectonic plates,       living organisms.
    which move slowly.     Theory of
 Atomic Theory            Evolution
   All matter is made       All life on earth
    up of atoms.              evolved from simple
                              forms.
       SCIENTIFIC LAW
 This is a statement of fact meant to describe, in
  concise terms, an action or set of actions. It is
  generally accepted to be true and universal, and
  can sometimes be expressed in terms of a single
  mathematical equation. Scientific laws are
  similar to mathematical postulates. They don’t
  really need any complex external proofs; they
  are accepted at face value based upon the fact
  that they have always been observed to be true.
 Specifically, scientific laws must be simple,
  true, universal, and absolute. They represent
  the cornerstone of scientific discovery, because
  if a law ever did not apply, then all science
  based upon that law would collapse.
 Some scientific laws, or laws of nature, include
  the law of gravity, Newton's laws of motion, the
  laws of thermodynamics, Boyle's law of gases,
  the law of conservation of mass and energy, and
  Hook’s law of elasticity.

http://wilstar.net/theories.htm
   EXAMPLES of SCIENTIFIC
          LAWS
 Ohm’s Law                        Law of Segregation
    I = V/R                          For any pair of
    Relationship                      characteristics there
     between current,                  is only one gene in a
     voltage, and                      gamete even
     resistance                        though there are
    Named after Georg
                                       two genes in
     Ohm                               ordinary cells.
                                      Founder – Gregor
 Newton’s Law s                       Mendel
    Objects at
     rest/motion stay at
     rest/motion until a           Ideal Gas Law
     force acts on it.                Combination of
    Objects will                      Charles's and
     accelerate in the                 Boyle’s gas laws.
     direction of the                 Formula: pV = nRT
     force (F = M*A).                 Relates pressure,
    Action-Reaction                   temperature, and
     forces (equal and                 volume of gasses
     opposite)
         For additional laws see this website:
             http://en.wikipedia.org/wiki/List_of_scie
             ntific_laws_named_after_people
KNOWLEDGE CHECK
1. What is the difference between
   a scientific theory and a
   scientific law?

2. Can a scientific theory change
   over time? Why?

3. List 2 examples of scientific
   theory and scientific law.
KNOWLEDGE CHECK
1. What is the difference between a
   scientific theory and a scientific law?
   Laws are generalizations about what
   has happened; Theories are
   explanations of observations (or of
   laws).
2. Can a scientific theory change over
   time? Why? Yes, as technology
   progresses, new evidence can be
   discovered helping to justify or
   falsify a theory.
3. List 2 examples of scientific theory
   and scientific law. Theory: Atomic
   theory, Big Bang theory; Law:
   Newton’s Laws, Law of Segregation
        MODELS
 Models are a visual representation
  that help scientists study something
  in more depth.
 There are 2 general types of models:
   Physical
     Models that you can touch
     Representation of an item they want
      to study
   Mathematical
   • Made up of math equations and data

   • They allow you to calculate things.
        MODELS
  BENEFITS               LIMITATIONS
 Models can be used     Scientists must
                          realize the
 for the following:      limitations of
   Study objects        models, especially
                         when reading the
    that are too         information
    small to see         obtained by them.
   Study objects       Because we may not
                         see an actual picture,
    that are too large   models are thoughts
    to see               and ideas from our
                         heads.
   Help explain the  Some calculations
    past and the         are very complex,
    present              and computers are
                         needed to find the
   Help predict the     answer.
    future
KNOWLEDGE CHECK
1. Why do scientists use models?


2. Describe the two main types of
   scientific models.

3. List 2 benefits of using models.


4. List 2 limitations when using
   models.
KNOWLEDGE CHECK
1.   Why do scientists use models? To help create
     a visual representation when studying
     something in more depth.

2.   Describe the two main types of scientific
     models. Physical – Hands on model;
     Mathematical – equation providing data

1.   List 2 benefits of using models. To help
     explain the past and the present, study
     objects that are too small/large to see

3.   List 2 limitations when using models. Some
     physical models are subjective since they are
     based on theories/observations; since some
     theories need computers to solve them,
     scientists must be able to read and interpret
     the data.

				
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posted:12/5/2012
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