Middle School Science 0439

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The basic process that drives scientific discovery.
The logical problem-solving technique that requires reasoning, skepticism, and direction.
Used by scientists to discover the truth, by confirming or rejecting hypotheses, thoughts, & ideas.

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Scientific Method

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10 Main Steps of the Scientific Method

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Observation
Research question(s)
Research
Hypothesis
Test of hypothesis
Analysis of data
If data supports the hypothesis, state a conclusion.
If data does not support the hypothesis, go back to Research.
Conclusion
Communication

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An unproved theory or educated guess to best explain a phenomenon.
Research and testing prove or disprove this.
A prediction that proposes the cause (independent variable) and effect (dependent variable) for the observed phenomenon.
Often written in the if-then format; if is the independent variable, and then is the dependent variable.

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Hypothesis

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A proven hypothesis that explains a set of related observations or relationships.
A statement of understanding, based on accumulated evidence that has been challenged by multiple peer researchers who have confirmed the statement of understanding multiple times in varying contexts.

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Theory

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States that the expected cause (independent variable) has no effect on the outcome (dependent variable).

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Null hypothesis

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A statement that confirms or rejects the hypothesis, and is based on the data collected for that experiment.
Should explain why the results of the experiment either proved or disproved the hypothesis.
If over time successfully withstand the intensive scientific scrutiny, review, and experimentation, this may become a theory.

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Conclusion

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Predicts events that occur with uniformity under the same conditions.

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Law

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A simplification or substitute for what we are actually studying, understanding, or predicting and is a basic element of the scientific method.

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Model
examples: The Periodic Table of the elements, continental drift model of continents

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In an experiment, the specific group that does not receive any treatment, and is used for comparison.
The experiment run under normal conditions.

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Control

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In an experiment, the group that is changed or manipulated by the researcher.

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Independent Variable

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In an experiment, the factor being measured.
What is influenced by the other variable.

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Dependent Variable

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An experiment that is run with one factor that is changed.

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Variable
examples: light, temperature, pH, time
**Only 1 variable should be tested at a time.**

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Misc. notes on researcher bias aspect of scientific method:
Scientists sometimes become so convinced that their hypothesis is correct that they over look a flaw or misread the data. The process of independent scientific investigation exposes researcher bias. Conclusions become increasingly valid as independent researchers confirm or deny results.
When designing an experiment, it is important to limit bias as much as possible. Scientific research can be biased in the choice of which data to consider, in the reporting or recording of the data, and/or in how the data are interpreted. The scientist's emphasis may be influenced by his/her nationality, sex, ethnic origin, age, or political convictions. Awareness of potential biases will aid you in planning your experiment.

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Misc. notes on researcher bias aspect of scientific method

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3 Common Characteristics applied to every aspect of the scientific method:

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Skepticism
Tolerance of uncertainty
Researcher bias

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Misc. notes on skepticism aspect of scientific method: Scientists are trained to treat new data with doubt. In reproducing another scientist's experiment or analyzing his or her data, scientists always look for the hidden uncontrolled variables that may have influenced the experiment and confounded the data. High standards in the judging of evidence and skepticism of one's own work are the mark of a good scientist.

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Misc. notes on skepticism aspect of scientific method

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The Pitdown hoax is a common example of the gullibility of the scientific community. This "discovery" of the missing link between man and ape at an archaeological site in England between 1908 and 1912 turned out to be a fake.

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Example of the need for skepticism aspect of scientific method

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Misc. notes on tolerance of uncertainty aspect of scientific method:
Researchers often discover that their data produce a piece of the puzzle, but not in the anticipated order. Productive research is similar to assembling a jigsaw puzzle. Scientists are trained not to ignore data that do not fit into their preconceived ideas or training.
The discovery and understanding of micro-RNA was delayed because of poor review of unexpected data.

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Misc. notes on tolerance of uncertainty aspect of scientific method

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Example of _________: In 1988, Jacques Benveniste was the center of a scientific controversy surrounding his research on histamines. Benveniste showed research data that "proved" molecules of water had memory and could be digitized and reinserted into another patient in need of histamines. Unfortunately, the scientific community was unable to independently achieve the same results after replicating the experiment many times. Further investigation showed that DR. Benveniste's salary and that of his coauthors was funded by a French firm that would likely have benefitted from his original results.

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Example of researcher bias

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Something that is always true, such as an incident that actually happened.

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Fact
Example: Gravity pulls all objects with mass toward the earth.

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In science, the test to determine if a concept is a fact.

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Verifiability
Facts are verified by repeated experiments conducted by different researchers who yield the same data.

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A formal scientific statement that describes a phenomenon that has been scientifically proven to absolutely and invariably occur under given conditions.
Held to be a true and universal statement of fact meant to describe a phenomenon.

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Scientific law

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In an experiment, the procedure used to create a fair test of a hypothesis. (A completely fair test is one that shows no bias or favoritism toward any variable, whether controlled or uncontrolled, within the experiment. In that way, the data accumulated may be attributed solely to the independent variable being tested.

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Scientific design

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The blueprint of the procedure for a fair test of a hypothesis. This design yields unbiased data, from which a conclusion is drawn regarding the relationship between the independent and dependent variables.
The logical and complete conceptual framework for an experiment and must be completed before the experiment begins.

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Experimental design

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Includes the problem statement, research questions, and hypothesis.

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Experimental design

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A clear definition of the problem to be investigated.

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Problem statement

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The selected participants in the group that is in keeping with the intent of the independent variable.

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Test group

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The population that will receive the independent variable "treatment".

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Treatment group

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Major source of experimental error and may render the data useless.

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Uncontrolled variables

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Examples of sources of experimental error:

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Human error
Instrument limitations
Manipulations
External influences
Poor experimental design
Sampling

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The father of microscopy who made magnifying lenses that allowed him to see and describe microscopic life. Discovered bacteria, blood cells, and parasitic protists.

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Anton van Leeuwenhoek

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Discovered the role of microorganisms in the cause of disease, pasteurization, and the rabies vaccine.

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Louis Pasteur

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Discovered that specific diseases were caused by specific pathogens.
Responsible for these guidelines:
The same pathogen must be found in every diseased person.
The pathogen must be isolated and grown in culture.
The disease must be induced in experimental animals from the culture.
The same pathogen must be isolated from the experimental animal.

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Robert Koch

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Discovered that the structure of a DNA molecule is a double helix.

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James Watson & Francis Crick

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Developed in the 1950s.
Instead of light, a beam of electrons passes through the specimen.
Has a resolution about 1000x greater than light microscopes.
Disadvantage is that the chemical and physical methods used to prepare the sample result in the death of the specimen.

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Scanning electron microscope (SEM)

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Oversees and evaluates all aspects of an institution's animal care and use program.

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IACUC: Institutional Animal Care and Use Committee

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400 BCE: The "Father of Medicine"; he located sensory areas in the brain and stated that diseases have natural causes, and he also discovered that head injuries led to impairments on the opposite side of the body. He developed the ___________ method of care, which was to leave the patient at rest until the sickness passed.

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Hippocrates of Cos
Hippocratic method

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280 BCE: The "Father of Anatomy"; he studied and compared human and animal anatomy, distinguished between sensory and motor nerves, distinguished between the cerebrum and cerebellum, and identified the "duodenum", the first part of the human small intestine.

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Herophilus of Alexandria

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260 BCE: Stated that the moon revolved around Earth, and Earth revolved around the sun; he also determined a body immersed in a fluid is buoyed up by a force equal to the weight of the displaced fluid, which is now known as ______________.

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Archimedes
Archimedes' Principle

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Calendar stones were used in Egypt.

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4800 BCE

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Copper smelting and irrigation were used in Mesopotamia.

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4000 BCE

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The wheel was invented.

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3500 BCE

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The first machines for moving water were invented to help agriculture.

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1500 BCE

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A continuous record of solar and lunar eclipses was kept in Mesopotamia.

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747 BCE

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600 BCE: Discovered status electricity.

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Thales of Miletus

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510 BCE: The first person known to conduct human dissections for medicinal purposes; he located the seat of perception in the brain, and stated that connections exist between human sensors and the brain.

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Alcmaeon of Croton

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500 BCE: He analyzed fossils.

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Xenophanes of Colophon

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440 BCE: Stated that atoms were imperceptible individual particles that vary in shape, size, and position, and compose the world.

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Leucippus of Miletus

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450-400 BCE: Described the atomic hypothesis.

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Democritus

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430-400 BCE: Proposed the immune system.

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Thucydides

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425 BCE: Compiled a history of science.

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Herodotus

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420 BCE: He further developed Leucippus' idea of the atom, stating that atoms vibrate when hitched together in solid bodies, and exist in an infinite space in which each star is a sun and has its own world.

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Democritus

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Babylonian astronomers correctly predict lunar eclipses.

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400 BCE

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330 BCE: Stated that Earth turns daily on its axis, while the rest of the heavens are at rest.

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Heraclides of Pontus

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323 BCE: Described and classified external plant parts from root to flower.

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Theophrastus

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260 BCE: He trigonometrically determined the size of the moon and its distance from Earth.

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Aristarchus

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50 BCE: Invented the first vertical water wheel.

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Vitruvius

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45 BCE: Designed a calendar with 365.25 days.

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Sosigenes of Alexandria

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62 CE: He displayed steam power and stated that the four elements were made of atoms.

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Hero of Alexandria

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170 CE: Used pulse taking as a diagnostic tool, studied human anatomy, and discussed "seeds of disease", probably referring to germs.

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Galen

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517 CE: Determined that objects fall at the same acceleration, which opposed Aristotle's idea that air was the motive force.

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John Philoponus

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530 CE: Wrote that gravity was the tendency of bodies to move to their natural place; he also claimed that gravitational strength is affected by the distance between the bodies.

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Simplicius

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Windmills were invented in the Middle East.

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600 CE

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700 CE: Began experimentation, which started the study of chemistry, discovering common acids, aqua regia, liquefaction, purification by crystallization, filtration, and sublimation.

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Jabir ibn Hayyan (Geber)

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The Chinese invented the first vision aids known as reading stones. The Assyrians may have used similar devices as early as 700 BCE.

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1000 CE

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1000 CE: Hypothesized two methods of mountain formation; deformation of the crust and erosion; he also wrote "The Canon of Medicine", in which he stated that medicines were to be known via experimentation or reasoning. "The Canon of Medicine" marked the beginning of experimental medicine and ushered in the discovery of the contagious nature of infectious diseases.

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Avicenna

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1000 CE: The "Father of Modern Optics" stated that light rays originated from a source and traveled in straight lines as well as in all directions.

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Alhazen

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1021 CE: Wrote the "Book of Optics", which began modern optics, including the scientific method and experimental applications to physics. He also correctly explained visual perception, binocular vision, atmospheric refraction, and, with Avicenna, developed a precursor to Newton's first and second laws of motion.

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Alhazen

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1020 CE: Began experimental astronomy and mechanics; he discovered the Milky Way Galaxy as a collection of nebular stars, determined that the speed of light was faster than the speed of sound, and developed a precursor to Newton's second law of motion, noting the relationship between acceleration and nonuniform motion.

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Abu Rayhan al-Biruni

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Chinese astronomers observed the supernova explosion within the Crab Nebula.

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1054 CE

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1121 CE: Discovered a variation of gravitation and gravitational potential energy at a distance; he also discovered the inverse relationship between decreased air density and increased altitude.

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Al-Khazani

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Alchemists further refined the process of distillation.

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1200s CE

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1242 CE: Described pulmonary circulation and parts of the circulatory system.

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Ibn al-Nafis

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1267 CE: Refined the use of the term hypothesis.

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St. Thomas Aquinas

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Italian doctors began writing case histories describing the symptoms and courses of diseases.

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1300s

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1323 CE: Distinguished between objects "being in motion" and "being moved", and added "Occam's Razor", which states that hypotheses should be stated as parsimonious as possible and that the simplest hypothesis containing the fewest assumptions is often the best one to use for experimentation.

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William of Occam/Ockham

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1350 CE: Opposed Aristotle's view on falling bodies and expanded on Philoponus's ideas of momentum an acceleration by stating that an object continues to accelerate as it falls.

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Jean Buridan

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1410 CE: Published an herbal notebook with 450 entries of plants, notes, and citations.

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Benedetto Rinio

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1444 CE: Stated that the Earth was in orbit around the sun, performed the first recorded biological experiment showing that plants absorb nourishment from the air, and created a hydrometer to measure atmospheric water content.

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Nicholas of Cusa

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1482 CE: Began assembling information on human anatomy, which was based on his dissections; these notebooks were later widely disseminated. He also compiled notebooks that contained thoughts on perpetual motion, machines, and statics.

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Leonardo da Vinci

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1512 CE: Hypothesized that Earth was a planet, and planets revolved in circles around the sun. He also noted the regression of planets. He further indicated that Earth rotated to form days and notable placed the sun at the center of the solar system, known as the heliocentric model.

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Nicolaus Copernicus

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1543 CE: He published meticulous human anatomy drawings, including organs.

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Andreas Vesalius

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1545 CE: He published drawings showing the venous and arterial systems, as well as the nervous system.

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Charles Estienne

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1556 CE: Classified minerals and referenced physical geography.

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Georgius Agricola

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1570s CE: Made detailed astronomical observations.

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Tycho Brahe