The Scientific Method

A method used to gain, organize, and apply new knowledge

Beliefs and Values vs Scientific Method

• Personal decisions vs measurable , physical characteristics

Typical Steps in The Scientific Method

• Question– Observe & recognize a

problem

• Research the problem• Hypothesis

– A testable proposed solution to the problem

• Experiment/test– Independent/dependent

variables– Control

• Analyze the Data• Conclusion

– No!! Yes!! I Don’t Know!

Parts of an experiment

• Independent variable– The thing the experimenter changes

• Dependent variable– The thing that is observed changing– Changes as a result of the changes to

the independent variable

• Control group– The standard in which all conditions

are kept the same

• Experimental group– The test group in which all conditions

are kept the same except for one (the independent variable

Types of data

• Quantitative data– Exact measurements– Numbers with units– Example: 100O C, 1.5 grams

• Qualitative data– Descriptions– Example: red liquid, hot, heavy

If your conclusion supports your hypothesis, it can become a . . .• Law (Principle)

– Hypothesis tested many times and never disproved• Example: Law of Gravity

• Fact– Something about which competent observers agree

• Example: Eating more calories than you burn off will result in weight gain.

• Theory– The simplest rule that organizes the hypothesis,

prediction, and experimental outcome.– Theory is not the end!

• Example: Theory of evolution

Serendipity (chance discovery)

Characteristics of living things

Growth

• The increase in mass or the number of cells

• (made of cells)

Cell division

Development

• The process of natural changes that take place during the life of an organism

Reproduction

• The creation of offspring

Stimulus / Response• Anything that causes

a reaction by an organism

• The reaction to a stimulus

• Wilting

Organization

• Arrangement in an orderly way.

• Potato cells

All cells require energy

Homeostasis

• Regulation of an organism’s internal conditions

Information (Adaptation)

• Inherited characteristics that results from changes to a species over time

• Genetic material DNA

Life Span

Abiogenesis Read chapter 14 sec. 2 pages 401-407

• The Spontaneous Generation hypothesis

• Earlier notions of abiogenesis, now more commonly known as spontaneous generation, held that complex, living organisms are generated by decaying organic substances, e.g. that mice spontaneously appear in stored grain or maggots spontaneously appear in meat.

Biogenesis

Ch 14.2 Origin of life

• Oparin’s Chemosynthesis Hypothesis

Miller & Urey 1953

• Organic Evolution• Experimented w/ gases

thought to be in the early atmosphere and created amino acids and other organic compounds.

• Since then, other scientists have refined the process and have produced amino acids, sugars, and nucleic acids (DNA)

REDI –Biogenesis pg 401

Maggots on cheese cloth

Pasteur pg 402

• Emperor Napoleon III asked Pasteur to investigate the diseases afflicting wine which were causing considerable economic losses to the wine industry. Pasteur went to a vineyard in Arbois in 1864 to study this problem. He demonstrated that wine diseases are caused by microorganisms that can be killed by heating the wine to 55deg.C for several minutes. Applied to beer and milk, this process, called "pasteurization", soon came into use throughout the world.

Louis Pasteur

• . His discovery that most infectious diseases are caused by germs, known as the "germ theory of disease",

• (is one of the most important in medical history. His work became the foundation for the science of microbiology, and a cornerstone of modern medicine. )

Joseph Lister

Joseph Lister used carbonic acid sprays and ether in the operating

rooms sterilization

Tyndall Experiment

• Dust in the air contained bacteria and spores. Sterilizing heat killed them

Endosymbiosis Hypothesis

• Engulfing of ‘primitive’ cells and incorporating them into the function of the ‘new’ cell.

Microscopes

Microscope Practice

Know parts for test

Microscope Field of View

Test over ch 1, 14, & microscope structures

and functions