The Nature of Scientific Investigation

Key Terms

fact
Galileo Galilei
hypothesis
law
Occam's Razor
theory

Chances are you are not a scientist (or even know any scientists). Yet we seem to rely on science so much to solve our many daily problems. This can be seen in the medicines we take, the high tech gadgets we use, and even the food we eat. Some people praise scientists for the lucrative lifestyle their technology produces. Others mistrust scientists for the new problems that arise from their work. Both views have valid points. There is very little doubt that science has yielded great benefits but also inflicted new dangers in our lives. However, most people should realize that "science" is only a process of learning. It is entirely a different matter deciding how that knowledge is used and who uses it. Let us try to separate these two different (important) aspects of science and concentrate on the former - the process of science. Somewhere in high school you surely learned about (or heard the phrase) the "scientific method". You probably got the impression that this is only something done by a nerd wearing a white jacket in some basement of a government-funded building. No! It is probably something you did recently! It is a common sense way of looking at something and trying to figure out "what gives???".

The Scientific Method

Suppose you were confronted with a problem or perhaps you observed something that puzzled you. What would you do, or how would you handle it? If you were to think like a scientist .... you would have to be open to new ideas. You must be willing to let go of traditions and "rules" which may have been handed down by authority and explore the possibility of a new way. Most teenagers have no problem with this!!!!

Example: Suppose you were a radio technician, and you kept getting unwanted radio static from your receiver. Most technicians would spend countless hours trying to find flaws in the way the radio was put together. But the technician who thinks like a scientist may explore the possibility that the radio is just fine ... there may be some kind of unknown radio signal hitting the antenna.

This is the next step ... offering an alternative idea to explain the problem. This is known as a hypothesis.

So, if the radio is receiving signals that show up as static ... what is the source of these signals? Are they coming from something local or from a distant place? Is the signal stronger in one direction than another?

So now comes the crucial step: a test! You set up your antenna and find it produces the same annoying static no matter which way you point it. You get the same thing day and night. You even go out of your way to eliminate all known sources of radio noise. It will not go away. The conclusion of the experiment: The radio could be receiving radio signals (noise) from all directions at all times! Does this prove that radio signals are coming from all directions at all times? NO! The radio could still be malfunctioning.

If this is the way you would have approached the problem ... too late! Arno Penzias and Robert Wilson received the Nobel Prize by providing the best evidence (in 1964) to support another idea that the universe started in a Big Bang.

A closer look at the process

Science is a process of learning about the world around us. It is based on the idea that everything in the universe works in ways that can be understood. That is, events and changes we observe do so because the behavior of all matter and energy are guided by certain fundamental "laws". The goal of science is to discover these "laws" and give understanding to the cause of events. This understanding allows us to predict the future behavior of the universe.

It is an unbiased way of understanding nature because it can be reproduced by anyone inclined to refute its claims. Because of the way science proceeds, it is always subject to scrutiny ... in science, nothing can be proven ... it can only be shown false. Let's look at the finer points of the scientific method.

An observer notices something and wonders why it behaves the way it does.
- The observer must be an unbiased observer.
- The observer must distinguish between a "fact" and a belief.
  - A fact is something all observers can agree on.
  - For example, if you look out the window and you see drops falling ... can you assume they are droplets of water? A fact is something any person in a similar situation would concur with. You might all be seeing droplets falling out your window. That is a fact! However, the belief that they are composed of water may not be true.
- This observation often leads to a question such as:
  - "Why is the sky blue?" or
  - "Why do objects fall?"
The observer develops a hypothesis or "guess" as to why the event occurred.
- There is an adage in science called Occam's Razor which states "all things being equal, the simplest explanation is usually the best explanation".
- The hypothesis represents a possible explanation of the event.
- This may invoke a prediction - a claim about what you think will happen in similar but slightly different conditions (based on the hypothesis).
The observer now tests the hypothesis
- This is what separates science from any other methods of finding the "truth".
- A good experiment is designed with controls which isolate your specific question (only one thing changes at a time).
- A good experiment is repeatable by you and others and must achieve the same results each time it is performed.
- If the test shows the hypothesis false, the hypothesis is rejected or modified.
- If the test confirms the hypothesis. The hypothesis stands.
  - The passing of the test does NOT prove the hypothesis true ... it only strengthens the hypothesis. Based on more confirming tests, the hypothesis becomes more "reliable" or "accepted" by the scientific community.
- The steps outlined above are a general guide to the way science works. On occasion, great discoveries are made by pure dumb luck. These serendipitous discoveries, such as the discovery of X-Rays and many others, are examples of scientific "short cuts" and can be considered a bonus.

Once, people thought that the sun (and all planets) moved around a stationary earth. This was known as the geocentric hypothesis ... in fact, it was the longest held hypothesis in the history of science. We all know now that it is wrong! Then Nicholas Copernicus (1543) postulated that the earth (and all planets) moves around a stationary sun (heliocentric hypothesis). He offered no evidence to support his position but invoked Occam's Razor to say that this is the simplest explanation. Can you offer any observable test to support the hypothesis of Copernicus? The test came from Galileo (click link 1.1.a to see how he "disproved" the geocentric model).

Why do we bring up Galileo Galilei (1564-1642)? Because he is known as the "Father of the Scientific Method"! Galileo challenged several "laws" proposed by the ancient Greeks. One dealt with the natural way objects fell. The Greeks (Aristotle) proposed that heavy objects fall fast ... light objects fall slower (ever drop a leaf?). Galileo proposed that objects fall at the same rate and then performed experiments to test his idea by simultaneously tossing objects of different weights off of tall buildings. He was the first to propose this method of investigation. Oh yes, the different weights hit the ground all at the same time.

Strengths of the Scientific Method

Unbiased - not subject to personal beliefs
Ideas are always subject to change ... so "time honored" beliefs can be rejected in light of new evidence.
When new ideas are advanced and/or new claims are made, the "scientific community" will carefully scrutinize all aspects of the idea in minute detail. This offers a system of "checks and balances" which upholds the integrity of the discipline. Only after the idea has withstood the rigorous inspection by the scientific community, will the idea gain credibility in the eyes of the public. On occasion, claims are leaked to the public before this check system has worked itself to completion. This is bad because it may lead to an embarrassing public retraction, but it also tends to "drag down" the entire scientific process in the eyes of the public. You should understand that this does happen on occasion, but this is NOT the way science is designed to work. Remember, scientists are people too ... often with big egos. Claims of cold fusion (link 1.1.b) and cloning breakthroughs (link 1.1.c) come to mind here.

The weaknesses of the scientific method are:

It is limited to testable questions only.
- Science cannot answer questions like "Do ghosts exist?"
- Science can answer questions like "Can light be used to transmit a signal?"
It is limited by the capabilities of our testing instruments.
Some observations and/or events may be controlled by so many different variables that it becomes difficult to obtain a clear picture. One example is the problem of "global warming". We have clear data suggesting the world temperature is increasing (a fact), but the exact cause (or to what degree) is not entirely clear. This is because some variables controlling global climate are the known increase in greenhouse gasses but also other factors such as volcanic activity (plate tectonics), solar activity, changes in orbit, etc. All play a part in changing global climate. It also becomes difficult to test these ideas because experimenting on a planetary scale is impractical and dangerous. Experiments using computer models are the best we can hope for ... for now.
Scientists are humans! Humans have egos, pride, and greed. In an effort to gain recognition, a scientist may try to "scoop" competitors by announcing a discovery to the press before the data has been reviewed by peers. A scientist could falsify data in an effort to gain fame or riches. Please try to remember that the process of science has only one goal - to seek understanding, and humans may have other agendas.

Fact, Hypothesis, Law, and Theory

The terms "hypothesis", "law" and "theory" are often used interchangeably in the general public (and are often used in the wrong context). However, to a scientist they are quite different - each having a well defined meaning.

Fact - knowledge or observation which is known to be true by all rational observers.

Hypothesis (see above) - an educated guess related to a specific observation or query. A hypothesis cannot be proven true but based on repeated testing, the validity of the hypothesis grows stronger until it is generally agreed (by the majority) that it is most likely true. Hypotheses deal with specific events. For example, if you observe that the population of one species of bird is decreasing in your area, you might hypothesize that the birds have altered their migration pattern.

Law - A law is a relationship between measurable quantities based on observation. It is often expressed in the form of a mathematical equation. For example, Newton's "inverse square law" of gravity calculates the force of attraction (F) between any two masses (M₁ and M₂) separated by a given distance (r) as:

Where G is a constant

Newton, himself, didn't understand why this relationship holds, but it is still found in astronomy books today. Does this mean the law is correct? True? Proven? No! Since "laws" are based on observation, they may be modified or "adjusted" based on more detailed information. For example, the ideal gas law (chemistry) works great under most situations, but does not take into account electrostatic forces between individual molecules and/or the container so the law fails under less than ideal conditions. However, a modification to the equation which takes these factors into consideration may work just fine.

The whole point is that a "law" shows us how measurable quantities are related under certain conditions but does not attempt to explain why they hold true. They are only based on observable facts. Although unproven, these "laws" are considered valid (accepted at face value by the scientific community) based on countless examples where the law holds up to rigorous testing.

Theory - A theory is a comprehensive explanation that governs the behavior of a phenomena or body of knowledge. It is much more encompassing than a scientific law and much more detailed because it attempts to explain why something occurs. A hypothesis might deal with a specific event, but a theory can be used to explain many types of events. For example, long after Newton's inverse square law was accepted by the scientific community, it remained a mystery why such a law should work. Einstein offered an explanation by suggesting that the properties of space are altered by the presence of matter - warping or curving it as the amount of mass increases. Wow! His idea was actually tested (twice) and after it passed the test, Einstein became a folk hero. To date, all predictions based on this theory have held firm. Now hold on ... does this mean that Einstein was correct? Sorry ... just like a hypothesis, a theory can break in an instant. Find one instance where it does not pass an observable test and a theory can go down in flames.

Theories are grand, bold ideas that revolutionize science. Often they are met with skepticism by the scientific community when first proposed. This is a good thing. A theory needs to be tested, tested, and tested again before it gets into the books. Once a theory has been offered, tested, and retested, it pushes aside older theories and sits on the throne. It is difficult to topple a theory once it is embedded in the scientific community. This is also a good thing because it offers a framework around which new research and ideas grow. Here are some grand theories the scientific community currently covets:

Kinetic Theory of Matter (which revolutionized chemistry) - All matter consists of basic building blocks. Quarks group to form protons, neutrons, etc ... protons, neutrons, and electrons group to form atoms. Atoms group to form molecules.

Plate Tectonics (which revolutionized geology) - The crust of the earth consists of separate plates which interact with each other to form mountains, earthquakes, and ocean basins.

Natural Selection (which revolutionized biology) - In any population, there will be individuals that are slightly more tolerant of changes in the limiting factors of the environment. When environmental conditions change, bringing individual organisms near their limits of tolerance, there will always be a few which are at least slightly more tolerant or BETTER ADAPTED than the population as a whole. The better adapted individuals will survive to reproduce. This passes along favorable traits to their offspring thus changing the overall traits of the entire population over time.

Why do we need to know all this?

It is important to understand the way science works. It gives you an opportunity to see that science is a journey, not an answer. This journey is filled with dead ends, rough roads, and many hills, but despite its flaws, it is a logical path to understanding the universe we live in. This class will be dealing with the way things work. In order to properly investigate the tools we use (technology) we must understand the scientific principles behind their operation. What better way to learn these principles than to discover them for yourself! My goal for you is to:

Develop a basic understanding of how common devices work.
Understand the underlying laws of nature these devices make use of.
Experience the method by which the laws of physics were originally formulated.
Observe similarities and common themes between objects and/or events.
Think logically in order to solve problems.

When you have finished this class, you will have a much better understanding about the world around you and, hopefully, acquire a sense of curiosity about things you still don't understand as well.