The Nature of Science

1. The Nature of Science Intuition leads to the flat Earth society and bloodletting; experiments lead men to the moon and microsurgery. - Seth Mnookin

2. Basic Rules of Science • Science is the pursuit and application of the natural and social world through the collection and analysis of evidence. • There are four major concepts in the pursuit of science: • Facts are observations that we make about the world. • Hypotheses are proposed, testable explanations of observations that can serve as a basis for experimentation. • Theories are much broader explanations of various observations that have been tested and confirmed through observation and experimentation. • Laws describe a constant phenomenon of nature, but do not explain it. Nearpod

3. Pseudoscience • A far different idea is pseudoscience – practices or beliefs that appear or claim to be scientific, but does not follow scientific principles. • The claim is not repeatable or reproducible. • The claim has no experimental evidence. • No alternative explanations for the claim have been tested. • There are many examples of pseudoscience throughout science, impacting the disciplines of biology, chemistry, and astronomy.

4. Spontaneous generation is a theory from the 4th century B.C. that life can arise from non-living matter. • This is based on observations, such as: • Beetles will appear in piles of animal dung. • Maggots will grow out of rotting meat. • Mice will generate from jars containing dirty garments and husks of wheat. • Fleas will arise from dust. • Spontaneous generation is considered pseudoscience, because: • No alternative explanations were considered. • No controlled experiments were conducted to test it.

5. The Four Elements theory proposed that all matter was composed of fire, air, water, and earth. • Alchemystudied ways to transform common substances (like lead) into gold through the manipulation of the four elements. • Alchemy is considered pseudoscience because… • The Four Elements theory was never experimentally tested. • Alchemists did not share or publish their results. The Alchemist in Search of the Philosophers Stone (1771) by Joseph Wright.

6. Astrology is the belief that the movements and positions of stars and planets affects the natural world. • The Zodiac Chart is based on what constellation the sun first crosses each day.

7. Astrology is considered pseudoscience because: • Predictions made by astrologers tend to be very generic and open to interpretation. • The Earth’s axis has shifted since the first chart was written 4,000 years ago. Nearpod

8. The Scientific Method • Scientists all follow the same basic set of steps when attempting to answer a question or explain an observation, called the scientific method. • The scientific method has been used in many important discoveries.

9. The First Vaccination • Smallpox was a deadly, contagious disease that called painful blisters all over the body. • The most common form of smallpox had a 30% fatality rate. • The disease is now eradicated, due to a discovery made by Dr. Edward Jenner, who employed the scientific method.

10. Scientific Method • The first step in the scientific method is making an observation, information gathered by noticing specific details of a phenomenon. • Dr. Edward Jenner observed that dairymaids who contracted cowpox seemed to be protected from the more deadly smallpox. The Dairy Maid, 1650s, by AelbertCuyp.

11. A hypothesisis atestable explanationor prediction based on the observation and the scientist’s prior knowledge. • Hypotheses are preliminary explanations and may be either supported or rejected. • Dr. Jenner’s hypothesis was that if a person was exposed to cowpox , they would become immune to smallpox.

12. The experiment tests the hypothesis under controlled conditions, with carefully defined variables. • The independent variable is the new factor or condition that is to be introduced and tested. • The dependent variable changes as a result of the independent variable, and will be measured and recorded as data. • Controlled variables are kept constant throughout the experiment. Nearpod

13. Dr. Jenner’s experiment was to an 8 year-old child with fluid from a cowpox pustule, allow the infection to pass, then repeat with a smallpox pustule. • Independent variable: The vaccine. • Dependent variable: Was the patient protected from smallpox? • Constant variables: Only children who never contracted smallpox were used. Nearpod

14. The boy survived 20 inoculations without succumbing to smallpox! • The conclusion states whether or not the hypothesis is supported by the results of the experiment. • Jenner concluded that his hypothesis was supported by his results. Nearpod

15. The final step is communication, where the results are published and reviewed by others to check for errors, bias, or other issues. • Dr. Jenner submitted his study to the Royal Society for Medicine, but was told he needed more proof. “The Cow-Pock—or—the Wonderful Effects of the New Inoculation!—vide. the Publications of ye Anti-Vaccine Society.” - Satirical cartoon, 1802.

16. Margin of Error • Accounting for every single variable in a scientific study is nearly impossible; there will be variability in all data. • Margin of error is an estimate of the amount of random sampling error in a set of data due to errors in measurement, experimental design, or other factors. • The margin of error can be reduced by increasing sample size, or the number of observations used in an experiment or study.

17. Dr. Jenner was able to locate several other parents who were willing to volunteer their children. He even included his own 11 month-old son in the study. • The results were finally published. Jenner called his technique vaccination after the Latin word for cow “vacca”.

18. Experimental Design • Controlled experiments aren’t always possible or ideal. • Natural experiments are conducted in the field under normal circumstances. • The advantage is that these experiments take place in a more accurate, realistic environment. • The disadvantage is that natural phenomena are often very difficult to find.

19. Combating Bias • Another significant problem in science is bias; the (accidental or intentional) preference for an experiment to turn out in a certain way. • Bias must be controlled by the experimental design. • A blind experiment is conducted so the experimental subjects do not know which is the control and which is the experimental group. • Eliminates the “placebo effect” • A double-blind experiment also prevents the actual scientists from knowing which is the control or experimental group. Nearpod

20. Scientific Fraud • Biased, flawed, or outright fraudulent results are always detected, due to the scientific method and peer review. • This costs time, resources, and increases public mistrust in science. • In 1998, Dr. Andrew Wakefield published a study in the British journal The Lancet documenting a link between the MMR vaccine and autism in children.

21. Although the study was retracted, much of the public trust in vaccines was shaken, and vaccine rates dropped in many countries. • Pseudoscience books, articles, and speakers against the use of vaccines have become increasingly prevalent, even though there is no evidence to support their claims.