2. SCIENCE

GeneralBiology_cool_Button1 Lecture Learning Tools Hub Slide Review Ch.1 & Ch.2

MAIN TOPICS OUTLINE

2.1 SCIENCE
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2.11 NATURE OF SCIENCE (Scientific Fundamentals)
2.12 SCIENTIFIC METHOD
2.13 CONTROLLED EXPERIMENT
2.14 THEORY AND LAW
2.15 SCIENTIFIC PUBLICATIONS (Not Covered This Semester)

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2.2 SYSTEM INTERNATIONAL (Metric measurements)
2.21 METRIC (SI) REFERENCE UNITS
2.22 SI SYSTEM PREFIXES
2.23 TEMPERATURE MEASUREMENTS

2.3 MICROSCOPY
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2.31 TYPES OF MICROSCOPES
2.32 COMPOUND LIGHT MICROSCOPE
2.33 BINOCULAR DISSECTING MICROSCOPE (Stereomicroscope)


LECTURE OBJECTIVES:

Differentiate between science, non-science, and pseudoscience.
Explain the underlying assumptions and the limitations of science, and understand that scientific 'fact' may change with changing scientific knowledge.
List the steps in the scientific method.
Explain the purpose of a controlled experiment, and understand the difference between a control group and a test group.
Differentiate between a scientific hypothesis, a scientific theory, and a scientific law.
List the SI-system reference units for scientific mass, length, volume and temperature measurements, list and understand the SI-system prefixes, and know some standard temperature points in the three temperature scales (Celsius, Fahrenheit and Kelvin).
Know how to use a microscope including the meaning of the term parfocal, know the various microscope parts, understand depth of focus / field of vision and understand how to calculate the total magnification.
Define selected key terms


Key Terms

def. Control: In a scientific experiment the version in which everything is the same as in the tested version except for the single factor being tested (= the variable).
def. Controlled Experiment: An experiment, in which two or more parallel trials are performed, that allows for a comparison, with trial conditions differing in only one factor. (A necessary procedure so that variations in results can then be reliably attributed to the factor tested.)
def. Control group: In a scientific experiment the group in which everything is the same as in the experimental group except for the single factor being tested (= the variable).
def. Hypothesis: A possible explanation (or answer) to a specific question about a specific phenomenon (one natural event), that accounts for all observed facts, and is supported by a test. ("an educated guess")
def. Law: A constant (or uniform) fact of nature, supported by (based on) several accepted theories -- or one elevated accepted theory.
def. Model: A simplified view of how things operate.
def. Non-science: A non-challenged, non-organized study of information.
def. Pseudoscience: Use of the appearance of science to mislead.
def. Science: A continually challenged, organized study of information (facts).
(Organized because the Scientific Method is used.)
def. Scientific Method: A way of gaining information (facts) about something
using a certain procedure (forming and testing hypotheses).
def. Theory: An generalized explanation of several related phenomena (natural events), supported by (based on) many accepted hypotheses.
def. Variable : In a scientific experiment, the factor being tested, the only factor in the experimental group that is not exactly the same as it is in the control group.





2.1 SCIENCE

2.11 NATURE OF SCIENCE

Definition of Science vs. Non-science, and Pseudoscience


Non-science: The scientific method cannot be used in certain areas.

-- art, literature, religion, philosophy


These areas are VALUE SYSTEMS -- beauty, emotions, faith, and speculation, based on VALUE JUDGMENTS not facts. Facts can be TESTED (a keystone procedure in the field of Science), VALUE JUDGMENTS cannot be tested.


Pseudoscience: looks like science, but is not. The scientific method is avoided in order to confuse and mislead (pretense that it is used).

-- e.g., the area of nutrition and medicine (advertisement).





Underlying assumptions of Science


deals only with what we perceive with our basic five senses.
-- vision, touch, taste, hearing, and smell
what we perceive functions according to certain basic principles that remain consistent through time and space.
-- principle of uniformity
all events are caused by natural phenomena
-- principle of natural causality (vs. supernatural forces)
we can discover and understand natural phenomena using a systematic form of inquiry.
-- the scientific method
(observations, speculations, and reasoning)




Limitations of Science


Science is concerned with the material universe:

(1) science discovers facts with the 5 basic senses
(2) science fits those facts into theories and laws


This creates the following limitations:


scientific conclusions must always remain tentative
-- hypotheses cannot be proven
scientific hypotheses must always be testable
-- this limits the range of science
science cannot deal with values
-- cannot make subjective value judgments


THE TESTING GROUND FOR SCIENCE IS THE EXTERNAL WORLD, NOT FAITH OR INTERNAL CONVICTION.






Scientific Fact is Open to Interpretation and Change


Question: Are scientists always right? (Does scientific fact change?)

def. Science: A continually challenged, organized study of information (facts). (Organized because the Scientific Method is used.)

Answer: No.

-- hypothesis tests can be misinterpreted
-- the wrong question may have been asked
-- scientific fact may change when new explanations are supported using the scientific method





2.12 SCIENTIFIC METHOD


In the next 20 years, the Earth's booming population and dwindling resources will force scientists and non-scientists to make many tough decisions. Educated men and women need to understand not just the 'facts' of biology, but also the ways that biologists go about learning and integrating knowledge.




Major Steps of the Scientific Method



Def. Scientific Method: A way of gaining information (facts) about something using a certain procedure (forming and testing hypotheses).



Five (5) major steps:



1. Observation of a phenomenon

i. -- basis of all scientific discovery (careful observation)

Scientists need to be curious and imaginative. No imagination = No knowledge. (Albert Einstein: "Imagination is more important than knowledge, and there is no completely logical way to a new scientific idea." In Miller, Environmental Science, p. 42.) Scientists need to be diligent (hardworking) observers. Many discoveries were chance occurrences (e.g., Fleming, Penicillin).

ii. -- we observe (perceive) with our basic five senses

See underlying assumptions above: Science deals only with what we perceive with our five basic senses (vision, touch, taste, hearing, and smell)



2. Asking a Question concerning the phenomenon



3. Hypothesis formulation concerning the phenomenon

def. Hypothesis: A possible explanation (or answer) to a specific phenomenon (or question),
supported by a test (and accounts for all observed facts).

i. -- must be testable (disprovable; a hypothesis NOT testable is of no interest to science)
ii. -- must account for all facts
iii. -- must be falsifiable (i.e., disproved so it can be eliminated, but cannot be proved)

4. Test of the hypothesis (attempt to disprove the hypothesis)

-- the test must be repeatable (allow for repetition by others)



5. Conclusion to accept or reject the hypothesis

If the hypothesis is:


rejected (falsified, fail to confirm):
-- the test is repeated or the hypothesis is eliminated
(use a modified or new hypothesis)

The test should be repeated because even if the hypothesis was rejected, it may not be the wrong explanation
-- e.g., bears eat berries vs. ‘wrong’ time of year]


accepted (confirmed, but always tentative, NEVER proven):
-- the test is repeated (-- to be sure; often repeated by peers)

A hypothesis can never be confirmed with absolute certainty. The statement "scientifically proven" falsely implies absolute proof. If a hypothesis is accepted it means that the hypothesis is a good explanation for the observation, with present day knowledge. But nothing is proven because new knowledge may change things.




Variations in the Scientific Method



Scientists debate and disagree as essential steps in the process of reaching scientific understanding.

Scientists often do not follow these steps exactly. The scope of biology is enormous. Every biologist has a unique view of the field as a whole.

Different fields of biology demand different working styles:
-- Descriptive science: only the first step (OBSERVATION).
-- Biochemist: experiment may only last a fraction of a second.
-- Ecologist: experiment may last a lifetime.


def. Model: A simplified view of how things operate.





The outline below illustrates the Scientific Method using 10 steps (i - x) subdivided into 4 major categories (1 - 4). Note, however, the 5 important steps outlined above are always there (observation, question, hypothesis, test, conclusion).


1. Observation of a phenomenon

i. OBSERVATION



2.
Hypothesis formulation concerning the phenomenon

ii. QUESTION


iii. EXAMINE PREVIOUS WORK
(Isaac Newton: "If I have seen farther than others it is because I have stood on the shoulders of giants.")


iv. MODEL


v. HYPOTHESIS


vi. PREDICTION



3.
Test of the hypothesis

vii. TEST

A. Further Observation
B. Controlled Experiment


viii. RESULTS (analysis of data)



4.
Conclusion to accept or reject the hypothesis (interpretation of data)

ix. REJECT Hypothesis or ACCEPT Hypothesis

same, modified or new hypothesis repeat test


x. - - - - CONCLUSION STATEMENT - - - -





2.13 CONTROLLED EXPERIMENT


def. Control: (= control group) In a scientific experiment the version (or the group) in which everything is the same (as in the experimental group) except for the single factor being tested (= the variable).
def. Controlled Experiment: An experiment, in which two or more parallel trials are performed, that allows for a comparison, with trial conditions differing in only one factor. (A necessary procedure so that variations in results can then be reliably attributed to the factor tested.)
def. Variable : In a scientific experiment, the only factor in the experimental group that is not exactly the same as it is in the control group


To test an hypothesis scientists must do further observations or do an experiment. A scientist must use CONTROLLED experiments to allow for comparison of experimental results (in the experimental group) with the results of a control (in a control group).

The design of a control is very important and not always obvious.

E.g., Trauma may effect the results when performing the experiment (e.g., giving a shot):
Solution: two controls.
Experimental group: given a shot with the experimental chemical
Control 1: given a shot with the control chemical (a placebo)
Control 1: given a shot but nothing is injected





2.14 THEORY AND LAW




Scientific Explanations beyond Hypothesis Testing



def. Hypothesis: A possible explanation (or answer) to a specific question about a specific phenomenon (one natural event), that accounts for all observed facts, and is supported by a test. ("an educated guess")
def. Law: A constant (or uniform) fact of nature, supported by (based on) several accepted theories -- or one elevated accepted theory.
def. Theory: An generalized explanation of several related phenomena (natural events), supported by (based on) many accepted hypotheses.


Hypothesis -- Theory (many hypotheses) -- Law (many theories)



1. Scientific Hypothesis:


-- specific, tentative, testable explanation, that accounts for all the observed facts, of a specific natural event


- - a "specific explanation" of one specific phenomenon


The hypothesis can then be tested further, and when this process has been repeated, and several scientists come to the same result and conclusion, eventually a biological theory can be formed.



2. Scientific Theory:


-- generalized explanation of several natural events, based on many supported related scientific hypotheses


- - a "generalized explanation" of several related phenomena


The theory can then be tested further, eventually a biological law may be formed.



3. Scientific Law:


-- constant fact of nature, based on several scientific theories, or one elevated theory


- a "very generalized explanation" of many complex phenomena


NOTE:

• The word HYPOTHESIS:

hypo = less, hypo-theory -- less than a theory.
The distinction between a hypothesis and a theory is only in the amount of information covered.

def. Hypothesis: A possible explanation (or answer) to a specific question about a specific phenomenon (one natural event), that accounts for all observed facts, and is supported by a test. ("an educated guess")


• The word THEORY:

Often non-scientists misunderstand what scientists mean by 'theory' ("just a theory"):
-- Non-scientist = speculation (untested idea).
-- Scientist = a set of interconnected, rigorously tested hypotheses.

def. Theory: An generalized explanation of several related phenomena (natural events), supported by (based on) many accepted hypotheses.

A scientific theory: a set of interconnected, rigorously tested hypotheses.





2.15 SCIENTIFIC PUBLICATIONS (not covered this semester)



Various forms of publications written by scientists



-- primary publication w. original research
-- secondary publication w. review of other peoples’ research




I. Scientific Journals
-- primary or secondary publications, peer reviewed, with a rigorous format

1. Research Paper
-- primary publication w. original research (follows the scientific format)

2. Research Note
-- primary publication w. short original research (may or may not follow the scientific format)

3. Review Paper
-- secondary publication w. review of other peoples’ research (regular cited essay style)

4. Monograph (usually a Masters thesis, or a Ph.D. dissertation)
-- primary publication w. original research, interm. between a research paper and review paper

-- secondary publication, review of what has been done in the original research field

-- scientific "book" -- a periodical article too thick to be called an article, but cited as if an article
-- written for specialists, scientists in a specialized, narrow field

II. Science Books
-- secondary publication

1. Text books
-- written for students & specialist in the field the text covers

2. Reference books
-- written for librarians, people working in the information industry, and students & specialists in the field the reference text covers: i. handbook, ii. encyclopedia, iii. dictionary

3. Trade books
-- written for the general public interested in the field the reference text covers
-- not very scientific, usually the books sold in bookstores




Other forms of publications with “science” writings



III. Book Reviews
-- secondary publication with a review (summary) of important points + evaluation
-- someone spared you the trouble of reading the book


IV. Scientific Magazines
-- secondary publication that have articles that may or may not be written by scientists
-- less rigorous format compared to journals

V. Other
-- secondary publications
-- Newspapers. Fiction. Nonscientific magazines. Advertisements. Personal publications. Propaganda.

-- SOMETHING A SCIENTIST MAY WRITE -- but these are NOT scientific publications! Some may be pseudoscience, and attempts to mislead.

The Internet? The WWW?
All of these publication forms listed above can be found on the WWW (in electronic form rather than on paper).







2.2 SYSTEM INTERNATIONAL (Metric measurements)




Easier to communicate if everyone uses the same system of measurement.



The Metric System, or the SI-system (System International)

-- the system of measurement units used in most of the civilized world

-- the system used for scientific work (including United States).

-- first adopted in France in 1795.

-- Even though the International (Metric) System received legislative sanction by the U.S. Congress as early as 1866, it has not yet become the accepted system of measurement in the United States.


Easier to use.


-- remember the reference units
-- multiply and divide by ten (10) --> easy to the calculations
-- remember the prefixes --> easy to understand the numbers


Decimal system 0.25 -- instead of 1/3 0.1 instead of 1/10 -- Calculators work on a decimal system

Convert between sub-units easy: 1m = 10dm = 100cm = 1000mm --> units of the metric system are related by (multiples of) the number 10

Inter-convert between different reference units is possible based on the definition:

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
1 kilo = 1 dm3 = 1 liter
or
1 g = 1 cm3 = 1 ml
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Note: standard reference chemical water at standard reference temperature 20°C

e.g., interconvert from liter (volume) gram (weight):

-- 1liter water = 1000g water





2.21 METRIC (SI) REFERENCE UNITS

Quantity Unit Abbreviation Conversion to U.S. unit
Mass gram g 1g = 0.035oz
Length meter m 1m = 3.28ft
Volume liter l 1 l = 0.26 gal
Temperature Celsius °C 1°C = 1.8°F


1oz = 28.35g 1ft = 0.31m 1gal = 3.79l



2.22 SI SYSTEM PREFIXES

Super-unit prefix



Tera– trillion 1,000,000,000,000 1Tm=1,000,000,000,000m
Giga– billion 1,000,000,000 1Gm=1,000,000,000m
Mega– million 1,000,000 1Mm=1,000,000m
Kilo– thousand 1000 1km = 1,000m
Hekto– hundred 100 1hg = 100g
Deca– ten 10 1dal = 10 l



Sub-unit prefix



Deci– 1 tenth 1 / 10 0.1l (e.g., 1dl)
Centi– 1 hundredth 1 / 100 0.01m (e.g., 1cm)
Milli– 1 thousandth 1 / 1,000 0.001g (1mg)
Micro– 1 millionth 1/ 1,000,000 0.000001m (1µm)
Nano– 1 billionth 1/ 1,000,000,000 0.000000001m (1nm)
Pico– 1 trillionth 1/ 1,000,000,000,000 0.000000000001m (1pm)
Femto– 1 quadrillionth 1/ 1,000,000,000,000,000 0.000000000000001m (1fm)





2.23 TEMPERATURE MEASUREMENTS


Presently 3 temperature scales are in use

Temperature unit Inventor Inventor information
Celsius °C Anders Celsius Swedish astronomer, 1701-1744
Fahrenheit °F Gabriel Fahrenheit German physicist, 1686-1736
Kelvin K William Thompson (Baron Kelvin) British matematician, 1824-1907



Celsius vs. Fahrenheit


- Different reference points used.

-- Water is used as reference chemical in the Celsius scale (visible boiling & freezing).

- The scale units between Celsius and Fahrenheit are not equal:
1°C = 1.8°F.

-- Because of the 0.8 unit scale difference the Fahrenheit temperatures in the table below are just approximate. Human body temperature of exactly 37°C translates to 98.6°F, or Absolute temperature -273°C translate to -459.4°F.

Conversion formulas:

convert to °F = (°C x 9 / 5) + 32 convert to °C = 5(°F - 32) / 9

or

convert to °F = °C (9/5) + 32 convert to °C = 5/9 (°F - 32)



A third temperature scale is the Kelvin scale – used in Chemistry



- - Same reference points used,boiling & freezing of water, but different zero points.
(no negative numbers in the Kelvin scale)
- The scale units between Celsius and Kelvin are equal: 1°C = 1K.

  Celsius Fahrenheit Kelvin
Boiling point of water 100°C 212°F 373 K
Milk Pasteurization 71°C 160°F 344K
Highest Recorded U.S. Temp. 57°C 134°F  
Human body temperature 37°C 98.6°F 310 K
Comfortable temperature 20°C Å 70°F 293 K
Freezing point of water 0°C 32°F 273 K
Freezer temperature -18°C 0°F 255K
Really cold weather (in ND) -40°C -40°F 233 K
Absolute zero -273°C -459°F 0 K


(exact absolute zero: -273.16°C, -459.69

The Celsius natural reference points are easy to observe and understand, and degrees Celsius (°C) are easy to use in calculations since there are 100 scale units between the reference points

-- Hence the incorrect but sometimes used name “centigrade”; Centi = 100.

In Fahrenheit (°F) there are 180 scale units; 212 °F - 32 °F = 180°F.

Because the Metric System is the accepted system of measurement in science, all measurements in biology laboratory exercises and class discussions will use this system.




2.3 MICROSCOPY

2.31 TYPES OF MICROSCOPES


(See lab manual)



2.32 COMPOUND LIGHT MICROSCOPE

(See lab manual)



2.33 BINOCULAR DISSECTING MICROSCOPE (Stereomicroscope)

(See lab manual)






GeneralBiology_cool_Button2 Lecture Learning Tools Hub Slide Review Ch.1 & Ch.2




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