The scientific method is a general approach to problems that involves making observations, seeking patterns in the observations, formulating hypotheses to explain the observations, and testing these hypotheses by further experiments.
Scientific methods in Chemistry
Chemistry is an experimental science. The idea of using experiments to understand nature seems like such a natural pattern of thought to us now, but there was a time, before the seventeenth century, when experiments were rarely used. The ancient Greeks, for example, did not rely on experiments to test their ideas.
What is the scientific method?
Although two different scientists rarely approach the same problem in exactly the same way, there are guidelines for the practice of science that have come to be known as the scientific method.
These guidelines or stages of the scientific method begin with the collection of information or data through observation and experiment. However, the collection of information is not the ultimate goal. The goal is to find a pattern or sense of order in our observations and understand the origin of this order.
As we conduct our experiments, we may begin to see patterns that lead us to an explanation or provisional hypothesis that guides us in planning new experiments. Eventually, we may be able to tie a large number of observations in terms of a single statement or equation called a scientific law.
What is a scientific law?
A scientific law is a concise oral explanation or mathematical equation that summarizes a wide variety of observations and experiences. We tend to regard the laws of nature as the basic rules under which nature functions. However, it is not so much that matter obeys the laws of nature, but rather that the laws of nature describe the behavior of matter.
Theory and model
At many stages of our studies, we can propose explanations of why nature behaves in a particular way. If a hypothesis is sufficiently general and continuously effective in predicting facts yet to be observed, it is called a theory or model.
What is a theory?
A theory is an explanation of the general principles of certain phenomena with considerable evidence or facts to support it.
As we move forward in this text, we will rarely have the opportunity to discuss the doubts, conflicts, personality shocks, and revolutions of perception that have led to our current ideas. We need to be aware that just because we can explain the results of science so concisely and neatly in textbooks, this does not mean that scientific progress is smooth, right and predictable. Some of the ideas that we present in this text took centuries to develop and involved a large number of scientists. We acquire our view of the natural world by leaning on the shoulders of the scientists who came before us.
There are four basic forces or interactions known in nature.
Gravitational forces or gravity
Gravitational forces or gravity act between all objects in proportion to their masses. Gravitational forces between atoms or subatomic particles are so small that they are of no chemical significance.
Electromagnetism or electromagnetic forces
Electromagnetism or electromagnetic forces act between electrically charged or magnetic objects. Electric and magnetic forces are intimately related. Electric forces are of fundamental importance in understanding the chemical behaviour of atoms. The magnitude of the electrical force between two charged particles is given by Coulomb’s law as follows.
Coulomb Law: F = kQ1Q2 / d2
- Q1 and Q2 are the magnitudes of the charges on the two particles
- d is the distance between their centers
- k is a constant determined by the units for Q and d.
A negative value for the force indicates attraction and a positive value indicates repulsion.
All nuclei, except those of hydrogen atoms, contain two or more protons. Because as the charges repel, the electrical repulsion would cause the protons to fly if a stronger force did not hold them together in the core.
Strong nuclear forces
The strong forces that prevent protons from separating are called the strong nuclear force. A strong nuclear force acts between subatomic particles that are extremely close to each other, since they are in the nucleus. At this small distance, this force is stronger than the electric force. therefore, the core holds together.
Weak nuclear forces
The weak or nuclear weak force is weaker than electronic force but stronger than gravity. We are aware of the existence of weak nuclear forces because weak nuclear forces manifest themselves in certain types of radioactivity.