Experiments

							                   Agree or Disagree?

• When cows fall asleep standing up, it is
  easy (and fun!) to sneak up next to them and
  tip them over.
• Birds eating rice thrown at weddings swell
  up and die (even burst).
• Animals exposed to radioactive waste
  mutate and turn into other types of animals.
                   Agree or Disagree?
• Earthworms come up onto the sidewalks
  after heavy rain to avoid being drowned in
  their underground tunnels.
• People licking toads have hallucinations.
• Lennon wrote better music than
  Tchaikovsky.
• Heaven is not in our solar system, but it is
  somewhere in the universe.
                     Science involves…

•   Using and extending the senses
•   Observing and collecting
•   Probing and testing
•   Deductive hypothesis testing
•   Inductive search for patterns
•   Building increasingly accurate explanations
    based on evidence
Mendeleev and the Periodic
Table of Chemical Elements
Fleming and the serendipitous
discovery of the first antibiotic
Goodall and the willingness to
       break with convention
                The Scientific Method

• There is simply no fixed set of steps that
  scientists always follow, no one path that
  leads them unerringly to scientific
  knowledge.
      “The Scientific Method”




1) Question or Problem   2) Hypothesize
3) Predict Consequences 4) Experiment
5) Interpret Experimental Results
                            Experiments
• An experiment is a test
  used to determine if
  there is evidence to
  support a hypothesis
                What is a hypothesis?

• A hypothesis is a guess or prediction about
  a phenomenon.

• Hypotheses can be stated as positive or
  negative.
• The “null” hypothesis predicts that there
  will be NO difference between experimental
  groups.
         Write your own hypothesis

• Write your prediction for the outcome of the
  radish seed experiment
• You should also provide a REASON…why
  do you think the experiment will turn out
  the way it will?
                      What is a theory?

• A theory is an explanation that has a very
  large amount of evidence to support it.


• A fact is an observation about nature. A
  theory is an explanation. So a theory can
  never “become” a fact.
                      Experiment Titles

• Usually, experiments are titled in a format
  like this:
• “The Effect of _______ on _________”

• Sample title: “The Effect of Light on
  Growth of Radish seeds”
             Experimental variables

• The ONE factor that you cause to be
  different between experimental groups is
  the MANIPULATED variable (also called
  INDEPENDENT variable).


• Sample: In the radish seed experiment, the
  manipulated variable is”Amount of Light”
             Experimental variables

• The factor that you measure as the outcome
  of the experiment is called the
  RESPONDING variable (also called
  DEPENDENT variable)
• In the radish seed experiment, the
  responding variable is ___________.
• The responding variable is LENGTH of
  STEM, measured in millimeters.
                                Constants

• All other factors in the experiment must be
  controlled so they are the same for all
  groups.

• Examples of constants in radish seed
  experiment:
• Type of Petri dish type of seed
• Number of seed           paper towel
• Water, Location    temperature
Measure the responding variable

• Draw a data table for recording radish plant
  sizes


   Date        Light             Dark
               Writing an experiment
                          description
• Title
• Hypothesis
• Short description of procedure
• Identify control and experimental groups.
• Name the manipulated, responding
  variables
• Identify five constants
                          Measurements

• Obtain a flexible plastic ruler and measure
  the length of the radish seeds today in
  millimeters.
• Record your data and your partner’s data in
  the data table.
   Fact, Hypothesis, Law, Theory

• Fact = a stated observation
• Hypothesis = a proposition that may
  be investigated
• Law or Principle = a description of
  observable phenomena
• Theory = an explanation based on
  extensive evidence
                     Big Questions
• What is LIFE?   • How can we tell things
                    that are alive from
                    things that were alive
                    or were never alive?
                        OBSERVING
                  LIFE and NONLIFE

• We now need to practice making
  observations of things and determining if
  they are alive, once alive, or never alive.


• This activity will allow you to practice
  writing CAREFUL and THOROUGH
  descriptions of what you see.
                        Life or Nonlife?

• Watch the short video clip of the Rover
  “Spirit” which is explored the planet Mars.
                       Life or Nonlife?

• Imagine that you have two soil samples
  returned from somewhere on Earth. Your
  job is to examine them, write a complete
  description of the objects you see, and
  determine whether objects are ALIVE,
  ONCE ALIVE or NEVER ALIVE
              Observing soil samples

• I will place soil samples on your desk:
  today you will examine soil from a
  DESERT.
• Observe a part of each sample in a half Petri
  dish
• Use a microscope and a magnifying glass.
              Observing soil samples
• Each person should write careful
  descriptions of soil samples
• Use as many adjectives as you can
• Describe size, shape, color of particles
• Explain WHY you think each object you
  see is alive, once alive or never alive
              Observing soil samples
• You will be able to add to your observations
  tomorrow.
• TODAY< before you leave, please add
  clean spring water (with no chlorine) to the
  DESERT SOIL only.
• Add water until the cup is half full.
• Water sometimes activates dormant living
  things.
                   Soil samples: Day Two

• Observe forest soil and desert soil again, adding to your
  descriptions of the objects you see in the soil.
• Make small drawings of any objects you see in the soil.
• Make note of any changes you see in the samples today.
• (Use a pipette to add a few drops of desert water to the
  Petri dish, so you can look at it under the microscope
• Then you will turn in your written observations on Friday.
Observing plant growth:
• Take bean and pea seeds and put them in
  containers of soil under our light source.

• Water them consistently.

• Each day in class, take note of any changes
  that you observe.
The Borderlands of Science
          Shermer, (2001)
     • Normal Science
        – Empirical claims
        – Vast body of evidence
     • Borderland Science
        – Empirical work
        – Growing body of evidence
     • Pseudoscience
        – Fake science disguised as
          normal science
        – Lacks evidence
        10 different areas of inquiry:
•   Acupuncture      • Heliocentrism
•   Astrology        • Hypnosis
•   Big Bang         • Neurophysiology of
                       Brain Function
•   Big Foot
                     • Punctuated
•   Chiropractic       Equilibrium
                     • Search for
                       Extraterrestrial
                       Intelligence (SETI)
                     The Borderlands of Science
                               Shermer, (2001)

•   Heliocentrism, .9
•   Neurophysiology of Brain Function, .8
•   Punctuated equilibrium, .7 ……normal science
•   SETI, Hypnosis, .5
•   Chiropractic, .4 ……………borderland science
•   Acupuncture, .3
•   Astrology, Big Foot, .1 ………pseudoscience