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.

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 is not backed by 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. This is based on observations, such as:
Spontaneous generation is a theory that life can arise from non-living matter.
This idea arose sometime in the 4th century B.C., and persisted through the mid-19th century.
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. Since the time of ancient Greece, many chemists believed that all matter was composed of four elements: earth, water, air, and fire.
Alchemy used this hypothesis to try to devise ways to transform common elements (like lead) into gold.
This led to many early discoveries in chemistry, such as Hennig Brand discovering phosphorous as he tried to isolate gold from his own urine!
Alchemists kept much of their research a secret, and this lack of knowledge sharing kept progress in the field of chemistry at a standstill for many centuries.
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.
This is partially based on the zodiac, a series of constellations that the sun crosses from the perspective of the Earth.
The original 12 zodiac signs were recorded by the ancient Babylonians in about the 5th century B.C., but are no longer accurate.
A “new” zodiac chart was created by the Minnesota Planetarium Society to reflect a shift in the Earth’s axis.

7. 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 to solve some of the greatest problems to face humanity, including the treatment of disease.

8. The First Vaccination
Up through the 20th century, one of the most serious diseases of mankind was smallpox.
The most common form of smallpox had a 30% fatality rate.
The only known “cure” was to contract the disease and recover.
Some inoculated themselves with fluid and pus from the sick, hoping to contract a mild case and survive.

9. The First Vaccination
A British physician named Edward Jenner observed that dairymaids living in his hometown often contracted cowpox, a nonlethal disease with similar symptoms to smallpox.
He decided to intentionally infect a young boy with cowpox, then expose him to smallpox.
Immunity was successfully conferred to the boy.
This discover serves as the basis for all vaccines used today, which have prevented over 700,000 deaths in the past 20 years alone.
Edward Jenner vaccinating a child with cowpox from a dairymaid. Source: Bettman Archive / Corbis.

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 Aelbert Cuyp.

11. The goal is to be able to explain the observation.
A hypothesis, or testable explanation, will be made based on the scientist’s prior experience and research.
Hypotheses are preliminary explanations – they can and are often not supported by the resulting experiment.
Dr. Jenner’s hypothesis was that if a child 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.
Dr. Jenner’s experiment was to inoculate the 8 year-old son of his gardener with fluid from a cowpox pustule, allow the infection to pass, then repeat with a smallpox pustule.
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.

13. 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,

14. 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.

15. 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”.

16. 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.

17. Combating Bias
Another significant problem in science is bias; the preference for an experiment to turn out in a certain way.
Bias is not always intentional, but 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.

18. Scientific Fraud
There are many examples of published studies or report that have been later found biased, flawed, or outright fraudulent.
These are always detected, eventually, due to the scientific method and peer review.
The net effect is loss of time, resources, and public mistrust.
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.

19. 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.
Similar movements can be seen opposing climate change and the use of genetically- modified organisms (GMOs).
“Green our vaccines” was a rally held in 2008 to raise awareness of supposedly toxic substances in vaccines.