In this discussion we shall examine the general nature of science, its subject matter, method and concepts. The aims is to situate science in a proper perspective so that the questions posed and the solutions proffered by Philosophers of science can be understood against the background of a large scientific and philosophical canvas.
The knowledge of scientific method will enable us to underscore the actual producer of scientific research a process through which we shall be able to carry out an informed evaluation of the various methodologies of science favoured by various philosophers of science.
To achieve this we shall also examine generalisations, explanations, and prediction in the sciences with a view to highlighting their common features. The questions of truth and certainty upon which the laws of nature are hinged will equally be examined.
In this section the subject matter and methods of the sciences shall be examined. In doing this, Astronomy, Biology, Physics and Chemistry will be our focus. We inquire into the differences, as well as the similarities between the afomentioned disciplines.
Astronomy, as a scientific endeavour, centres on the investigation of the location, magnitude, motions, nature and constitution of Celestial bodies and structures. The early beginning of astronomy is linked with the activities of the gods. This explains why priests of primitive religious were interested in astronomy. Celestial objects, most especially the sun, moon, and planets played significant roles in primitive superstitious religion. The priests anxiously observed the skies as a symbol of worship.
Astronomers have since progressed beyond this primitive stage. Nonetheless, modern astronomers, "try to gain understanding of the universe by stuying it different parts." (Abott, 1984:3)
The sky remains the main point of emphasis of astronomy. By a deep scrutiny of the stars, astronomers are able to penetrate the relationship between the stars and nature.
Celestial Navigation
Celestial bodies are things that related to the sky or visible heaven. Celestial navigation, on the other hand, centres on the attempt to probe into the celestial bodies. It is a means of equiry by which a geographical location is determined by making reference to the position of the celestial bodies. The universe on the other hand, can be conceived as the totality of existing or created things. This includes the earth with everything in it, the heavenly bodies and everythings inhabiting the space or the cosmos, including mankind.
A person position on the surface of the earth is determined by the observations calculations of astronomers after a careful observance of the heavens. Their discoveries are made up of enormous data based on the apparent day-by-day movement of the Moon Jupiter , Venus, Saturn, Mars and a number of bright stars. The findings of the astronomers are usually recorded in nautical and air almanac published annually by the governments many countries. As Graham and Murray (1979:165) point out,
Navigations by air or sea observe these heavenly bodies and compare their findings with the data given in almanacs. They can determine their position with amazing degree of accuracy.
As a result of advancement in science and technology, electronic devices have been developed which guide navigators of ship or planes. Nervertheless, a thorough knowledge of celestial navigation proves invaluable when the electronic equipment fail.
Also, the orbits of the comets and asteriods are studied by the astronomers. They chart the positions of the stars in the skies, determine their composition and study "the transformations of the atoms of which they are composed" (Abott, 1984), With their sophiscated telescopes, they are able to speculate about the number and origins of the distant galaxies
click to view AstronomyA number of astronomers had actually made commendable attempts to speculate on the structure of the universe. For instance, the astronomer Ptolemy thought and believed that the earth was at the centre of the universe and that the sun and planets revolve around the earth Copernicus was to prove this wrong as he established that the earth, Moon and Planents revolved around the sun. He was nonetheless wrong in thinking that the orbits were perfect circles.
Astronomers have made tremendous breakthrough that are of immense benefit to both scientists and laymen. They have enhanced the advancement of physics and chemistry.
The stars are laboratories in which physical and chemical theories can be tested under condition of temperature, pressure, velocity and density that could not be duplicated upon the earth. These celestial laborataries have already helped us fill many a gap in our knowledge (Abott, 1984)
Astronomy also contributed much in the advancement of the study of atomic energy. Before man was able to split an atom, he needed to have an in-dept knowledge of the structure and behaviour of atoms naturally therefore, the astronomers had to supply a good deal of useful information based on the study of the atoms of the sun and other stars, they were able to establish that the release of energy from these celestial bodies must have resulted from these atoms. In the same vein, they showed the extensiveness of this energy outpouring.
The sun for example releases into space about 2,000,000 times as much energy as the earth receives from it. Yet the tiny fraction we receive is ample for our needs and supplies us not only with light and heat but even with life itself (Abott, 1984) 41.
The New Elements
The astronomers are also responsible for the information provided on the dark areas of the sun's surface known as sunsports. Scientist has investigated this nd concluded that the sun sports affect rainfall and weather in general. it is believed in the scientific circles that a thorough knowledge of the relationship between sun sports and weather will make it possible, some day, to predict both times of bumper harvest and famine.
In the ancient days the eclipse of the moon and the sun was terrifying to people. The Chinese of the ancient period were of the view that solar eclipses were caused by a great Dragon trying to swallow the sun. This kind of mystic notion died as soon as men learnt that eclipses take place when the earth gets between the sun and the moon. Until recently, the appearance of a great comet in the sky was seen as portending dreadful events like pestilence, drought, or the death of a king. When Edmund Halley, a contemporary of sir Isaac Newton, predicted the return of the comet that now bears his name, he remarkably demystified this superstitious given that his prediction came through. Through Halley's work the comets were tamed once and for all and thus, through him, all the superstitious, beliefs about the comets lost credibility.
An astronomer requires the knowledge of mathematics, chemistry and physics to be able to operate successfully. He constantly applies the laws and theories of physics and mathematics in order to grapple with the activities in the skies. He requires the knowledge of chemistry to carry out his study of the composition of the sun and stars, theoretical astrophysicists (those that are concerned with the stars at advanced physical laboratories) study the observation and theories of the past and make prediction concerning the heavenly bodies. It is not always that their predictions comes through. New physical properties could suddenly come into existence, thus thwarting the basis of their predictions.
Method in Astronomy
The method usually adopted in astronomical research is quite different from what obtains in Physics, Biology and Chemistry. Astronomers use scientific instruments such as telescope with which they speculate about the numbers and origins of the distant worlds, and the structure of the universe. They also used the spectroscope to observe the planets and make predictions. Their findings are equally recorded as data and verification taken. But it has to be remarked that much of their work is done by observation; they hardly get into physical contact with the objects of their enquiries. This fact contributes in a large extent to the proberbility of occurence of their predictions and this explains why astronomical research is based on trial and error.
Biology
Biology is concerned with the study of living things plants and animals. We know from common sense that certain things are living while others are not. Biology centres on the study of the characteristics of life, of plants and animals. All living things are made up of protoplasm. This protoplasm which is a complex substance is arranged in cells. To study protoplasm is to study life. The activities of living things take place in this complex substance. It is noteworthy that certain organisms such as viruses do not have protoplasm and cellular structure and yet they are classified as living things.
Living things irritatable. By this is meant that living things (men, animals, trees, etc.) respond to changes in the environment. And this is expressed in movement. Nevertheless, water which is not a living thing responds to external forces. For instance, gravity causes it to flow from a higher to a lower level. Living things, respond to both internal stimuli as well as external forces. Whenever there is a change in its internal structure, it is easily noticeable in a living thing. It is also easy to notice its response to external forces.
Growth is another essential feature of life. The manner of growth of living things is quite different from that of non-living things.
Things that are not alive are capable of growth only by accretion that is by adding to their existing bulk, a mass made up of the same substance. In this way, river increases its size as brooks flow into it. An icicle becomes bigger as more water is added to the core of ice and is frozen in its turn (Graham, 1979:375).
It has to be noted, however that the water in the enlarged river has not changed- it is still remains water. A child, who typifies living things, for instance develops by taking into its body food that is chemically different from itself. This food is chemically transferred and part of it forms part of the body of the child.
Reproduction is another essential feature of living things. They (living things) reproduce their kind trees yield seeds which invariably develop into trees. Non-living things do not posses this quality. It is through reproduction that living things regenerate themselves. It used to be believed earlier that;
aphide or plant lice come from dew in plants, that maggots were for med from decaying meat, that horse-hair turned into worms, that the mud of the nile gave forth fishes. We know now that aphide maggots, worms, and fishes are all produced from eggs that are laid by the adult female (Graham et al, 1979:376)
Reproduction or procreation is the exclusive preserve of living things. Viruses are the only exceptions. They are sometimes known as filtrable viruses, for they can filter through any porus mass. They cannot be seen through the ordinary microscope hence they are called ultra microscopic virus.
They live and reproduce in the living cells of more complex organisms where they can cause diseases such as small pox, measles, cold , cancers, influenza and rabies. When viruses hooked up to certain living cells of some organism, they dissolve their way into the cells and make use of the protoplasm to reproduce themselves. The cell suffers destruction as a result of this.
Physics
Natural Philosophy was the name given to the study of material things up to the end of the 18th century. As human society advanced in scientific breakthroughs, the need arose to arose to divide the study of nature into two main branches-the physical science and the biological sciences.
The physical sciences, which include physics are concerned with the study of the properties and behaviour of non-living matter.
Whereas Chemistry is concerned with the action of kind of substance on another. Physics centres essentially on matters relating to energy. we are said to be studying Physics when we are concerned with energy and the laws in which it can be transformed from one form to another and the laws governing the process.
The study of Physics could be grouped under the following headings: Mechanics, Optics, Motion, General Physics, Waves, Magnetism and Electricity. At an advanced stage, we can talk about particle physics which centres on the altimate particle of which matter is composed. Nuclear physics deals with atomic nuclei and plasma physics has to do with researches on the production of energy. Physics can equally be applied to researches in other seemingly unrelated fields such as: medicine and surgery. The wave motion is particularly essential in X-ray matters.
In Physics, we measure certain properties of matter, and result are evaluated to help ascertain if there is any mathematical relationship between them. Also there is a frequent use of equation in Physics. The essence of this is not so much to reveal things as they are in themselves, but to express the laws governing their behaviour. This is the pivot of science-to seek out the laws of the universe and if possible to put the same in a simple mathematical form. Hence the view that technologists use this information for such purposes as designing of electric dynamos and motors, radio, television and radar of installation, artificial satellites, space craft and nuclear power. Material well-being has been remarkably improved as a result of these science functions. All measurements in physics includung such things as electric current are related to the three chosen fundamental quantities of length, mass and time. They give us the structure of our object of interest.
Common Terms in Physics
Force: Force is generally understood to connote push or pull. At any point in time a body is acted upon, it is expected that a force may alter its speed or its direction of motion or else bring it to rest. Force can thus be seen as that which changes a body's state rest or uniform motion in a straight line. A force can equally be said to be responsible for the acceleration of a body. One unit of force is thus defined in terms of the acceleration produced when the force acts on a mass of one kilogramme. This unit of force that is known as the Newton (N) is defined as, "the force required to give a mass of one kilogramme an accelerationof one meter per second" The Newton derives its name in honour of sir Isaac Newton who laid the foundation for the study of the relation between force and motion in the 17th century. A Newton is roughly equal to the weight of 100g mass.
Gravitational Force: The force we are most familiar with is that which pulls us towards the earth. This kind of force is known as gravitation. Newton pointed out that gravitational force exists between all bodies. For instance, two stones are both attracted to each other as well as attract each other. This force cannot be noticed because of its minimal nature, but its measurement can be carried out with sensitive instruments.
Gravitational attraction is applicable to all masses no matter where they are located. This according to Graham and Murray (1979:165)
Explains why a base ball falls to the ground when it is dropped from the hand, why a rope sags when it is slung between two poles, and why planets keep whirling in their orbits around the sum(Graham. et al, 1979:165).
It is noteworthy that the force resulting from gravitational attraction acts on all bodies involved. The earth which has a mass that is far greater than that of the moon attracts the moon through the force of gravitation. The moon equally attracts the earth. Our assumption is that the earth and the moon are moving about a common centre. This is much closer to the centre of the earth than that of the moon as a result of the difference in their masses. Thus,
Newton's law of universal gravitation states that any two particles of matter attract one another with a force which is proportional to the product of their masses and inversely proportional to the square of their distance apart (Abott. 1984:13).
Newton states that gravitational attraction is applicable not only to bodies on the earth, but is also responsible for holding the moon in its orbit arround the earth. The same holds for the earth and its fellow planets in their orbits round the sun.
Centripetal Force: For a body to be kept moving in a circle, there must be a force directed towards the centre. This force is known as centripetal force. Before Newton, the erroneous belief was held that invisible spokes radiate out from the sun and push the planets around. Newton's investigation revealed that this kind of push was not necessary:
The planets carrying their atmosphere with them go on moving in their orbits because the great vacuum of space offers no opposing force to their motion.
Centripetal force is however required to produce the continuous change of direction which occur in the orbit and this is provided by gravitational force. (Abott. 1984:41)
Work and Energy: At any point in time a force produces motion, work is done. For instance, a locomotive pulling a train does work; so does a crane when it raises a load against the pull of the earth"(Abott, 1984:73). Work is done whenever the point of application of a force moves and its measurement is by product of the force and the distance moved in the direction of the force.
However, that has the capability to do work is said to have energy. Energy is thus the capability to perform work. In the universe energy manifests in different forms and chemical energy is divided into two kinds namely, potential and kinethic energy. Kinetic energy is the energy which a body has by reason of its motion.Speed is another important concept in physics, especially in the area of mechanics. And it speed is seen as the rate of change of distance moved with time. If distance is divided by time we get average speed, that is,
average speed = distance/time.km/h
In discussing speed, such topics as distance and displacement are broached. If for instance, we say a motor car travels distance of 100m, the expression. 100m stands for a scalar quantity (a scalar quantity is that which possesses magnitude (or size only). But if the car moves in a straight line and we mention the direction of travel. For instance 100m due east, we are then dealing with a vector quantity (a vector quantity is one which has direction in addition to magnitude ) and this is known as the displacement of the air. Thus, displacement can be defined as distance covered in a specified direction.
In the area of heat, temperature is a recurring concept. The temperature of a given substance is the number which indicate its degree of hotness or coldness on some chosen scale. Temperature is measured by means of a thermometer, of which a number of different types are available. But for accurate scientific work, this temperature is measured by means of a thermometer, of which a number of different types are avialable. But for accurate scientific work, this temperatures are often measure by platinum resistant thermometer. This consists of a fine platinum wire contained in a silica tube. Temperature changes are calculated from the changes in electrical resistance of the platinum. The principle underlying the graduation of all types of thermometer is to choose two fixed and easily obtainable temperature called the upper and lower fixed points and then to divide the interval between them into a number of equal points or degrees.
Newton's Laws of Motion
Galileo was the first scientist to initiate studies on the behaviour of falling bodies. Hitherto, scholars upheld the thesis of Aristotle to the effect that the rate of fall was proportional to the weight of the body.
This, Galileo showed was a conclusion erroneously drawn from the fact that air resistance showed the fall of light objects that offered comparatively large area to the air. Objects that were heavy enough and compact enough to be neglected fell at the same time (asimov, 1975:92).
Isaac Newton furthered the work started by Galileo on moving, bodies. He summed up Galileo's principles of motion (which centered on the study of motion) particularly those of the planets and other heavenly bodies into three basic laws.
laws of motion describe what happens to a moving object. Once we know the laws of motion we can predict the future of a moving object provided that we know certain things about it initially. (Gary-Zukay, 1979).Our predication becomes more accurate depending on the credibiity of the initial information gleaned from the object in reference. The first law states that whenever an object is moving in a straight line, it will not be diverted unless it is acted upon by force. 'Inertia" is the term given to the tendency of a body to remain at rest, or if moving, to continue in a straight line untill it is acted upon. Due to this, Newton's is called the law of inertia. The second law of motion states that the rate of change of momentum of a body is proportional to the applied force and take place in the direction in which the force acts. (Abott. 1984:36). The third law of motion states that whenever a force act on one body, an equal and opposite force acts on some other bodies. This is at times summarised thus. "To every action there is an equal and opposite reaction". It is to be noted that (the) action and reaction act on different bodies.
Newton was convinced that his laws were the outcome of thorough experimental works.
His critertion for the validity of everything that he wrote was that anyone should be able to reproduce his experiments and come up with the same results. If it could be verified experimentally it was true. If it could not be verified experimentally it was suspect (Zukay, 1979:48).
Newton, as we can see from the above, believed that one of the aims of science is the search for truth. He therefore reasoned that the only way we can demonstrate the validity of a law is by repeated experimention and verification of our thesis.
Newton's first law of motion is philosophically significant because it made it no longer necessary to support that "heavenly bodies moved because nothing existed in outer space to stop them after the initial impulse" (Zukay 1979). The second law of motion conceives force in the line of mass and acceleration. His effort in the above direction represents the first clear distinction between the mass of a body and its weight. It is to be recognised too, that Newton's gravitational law was influencial and useful in explaining the motion of the heavenly bodies.
Method in Physics
Measurement is a common feature in physics. Generally, measurement is related to three fundamental quantities of lenght, mass and time. Some of the instruments used in measurement in physics are cylinder measuring flask, pipette and burette.
Experiments in physics are essentially conducted for the verification of physical laws. In doing this, careful weighing and measurement are carried out to establish the behaviour of particles of matter (when) in motion and at rest. To know the method applicable in physics is the same as knowing the steps of carrying out experiments in it. In such experiments, a number of factors are involved. First is the statement of problems which scientists aim at solving. Second is the search and assemblage of appropriate apparatuses necessary for the experiment. Following on this is the question of the technical skill.
Is the researcher technically equipped for the experiment? Furthermore, there is the need for survey of the ways in which past scientists executed this experiment, the basis upon which the present crop of scientists state the condition under which they wish to carry out their own experiment.
Having done this, they begin with the test. When the test is completed, reading will be done alongside the collection of other information. Thus is usually done at the observation stage. When this is complete, then the researchers should state their conclusion in clear terms. In this spirit Newtonian physics was able to establish, for instance that;
the various irregularities in planetary motion were seen to be the result of their minor attraction (perturbation) for each other super imposed on the gigantic attraction of the sun. It even accounted for the complex variations in the motion of the moon (Asimov, 1975:138).
From the above knowledge, Aristotelian view that heavenly bodies were united in perfect harmony lost most of its relevance and credibility. It can be further learned from Newtonian physics that the universe is governed by laws that are susceptible to rational understanding. By the application of these laws, the knowledge of the universe was enhanced and this, invariably influenced our environment. A typical experiment in physics seeks to compare thermal conductividies (Abott, 1984:187)
A. Apparatuses
i. rods of wood and Copper
ii. Bunsen burner
iii. A piece of paper
iv. A lathe
B. Test
One end of a wooden rod is to be turned down so that it will fit into a copper tube of the same diameter. When this is done, the two materials (wood and copper) will form a single rod of uniform diameter. Having done this, a piece of paper is struck round the joint to ensure that the wood and the copper are covered equally. The rod will be passed through a bunsen flame as many times as possible.
C. Observation
It will be noticed "that the paper chars where it covers the wood, but remains unharmed where it covers the copper. Copper conducts the heat from the paper so rapidly that it remains comparatively cool" (Abott, 1984). The wood in contrast conducts the heat very slowly from the paper" with the result that its temperature quickly rises to the point at which it begins to burn" (Abott, 1984:188).
D. Conclusion
Copper is seen to be better conductor of heat than wood.
Chemistry
Chemistry is indispensable to ma. There is handly any human activity that does not involve chemistry. Man is perennially in contact with chemicals and chemical changes like soap, tooth-paste and the beverages he consumes from time to time. The food, drugs, clothes and even the air that catalyse man's health and existence are all chemicals and as Miller (19811) puts it.
Chemistry is thus the pivot of man's life or existence. The existence of chemical science predates history. However, the development of the science in human society has been made possible by chemical science. A knowledge of chemistry is needed for a deeper understanding of the universe. i.e. the stuff it is made of and its structure. The development of chemistry and its contribution to human development were brought about by the unlimited capacity of manto observe his environment and thus concomitantly question certain phenomena or realities. In this light, Miller (1981), has further observed that:
The story of the evolution of today's chemical concepts is filled with heroes who dared to question existing ideas, with demagogues who tried to mislead and with scientists engaged in honest and open disagreement.
We shall examine in the course of this study, some of the controversies rife in the study of chemistry and how they have helped in the advancement of the scientific enterprise generally.
Among other factors, metallurgy played the most singnificant role in the development of chemical science. Seven main metals were known in the ancient period viz: gold, tin, iron, lead, silver and mercury. A part from gold and silver, these metals usually not palpably noticed in nature. Before the metals were obtained, the process of smelting, which consisted of heating the ore had progressed to advanced stage culminating in the dawn of the iron age. Copper and lead were also needed by plumbers, especially those building the ancient Egyptian temples. Since gold was the most percious of these metals, the others were therefore utillised and processed to obtain more gold.
A seminal scholarly work on the development of chemistry was done in the Greek World. Thinking about the material structure of the world, Empedocles (490-430 B.C) proposed that all materials were composed of four elements. These are earth, water, air, and fire, in various propotios. The existence of the three was in keeping with the observation that matter is either solid (earth) liquid (water) or gaseous (air). Fire was included to underline its importance in effecting changes of material substances. Aristle explained this theory by including the conditions of dryness, wetness, coldness and hotness to agree with the above elements. Hence, he stated that for fire is hot and dry, whereas air is cold and moist, while earth is cold and dry, "(Miller, (1981:2) Aristle further, posited that any of the four could be interchanged through an alternation of its properties. Thus, water could be changed into air, if coldness were replaced by dryness. This thesis was mainly based on observation. From a burnt wood are emitted flame, air (smoke) and possibly water, i.e on the condition that the wood was green. Earth (ash) becomes the residue. This idea which was borne out of an over simplification of the activities of nature did not hold survey for too long.
Another salient contribution made by the Greeks in the development of chemistry was their belief in the posibility of the infinite divisibility of matter. However, Democritus thought otherwise. He believed that there was a limit to the divisibility of matter. For him, at some point, small particles cannot be divisible. Hence, he conceived the idea of atoms, which (for the Greeks 'atom' means indivisible) to him, was the smallest indivisible particle of an element. This idea was later to because a landmark in the development of the science of chemistry. Serving, as it were as the fountain head of such theories as Dalton's atomic theory.The Alchemists
Generally, alchemy is accepted as the forerunner of the science of chemistry. It started cury into gold or silver (transmutation). They reasoned that every material was a blend of earth, water, air and fire. They thought too about changing the combination of these four elements in a material into another one. Lead, they claimed, was almost as dense as gold, and copper possessed a similar colour. Thus, they thought it would be easy to convert these two metals into gold. Unfortunately, when experimented, this experiment failed abysmally.
Paracelsus, one of the alchemists, had to redirect the efforts of the European alchemists to a more fruitful gaol, by experiments and their systemization. This new effort led to the discovery of new substances and invention of laboratory apparatuses for distilation and recrystalization. In this respect, observation and recording of some fundamental chemical behaviour became imperative. All this led to the emergence of chemistry as a useful branch of science and hence, led to the censation of the alchemists' inordinate ambition to transmute base metals into gold.
The Phlogiston Theory
The four elements basis for alchemy was finally debunked by the findings of two German Physicians, Johann Becher (1635:1682) and George Stahl (1660:1734). This development constituted another land mark in the future of the science of chemistry.
It was commonly observed that when combustion of say, wood, paper or metal takes place the flames escaped and ashes were left. Becher and stahl inquired and reached the conclusion that combustible materials contain a substance, phlogiston, which escapes during combustion. They believed that paper and wood have lots of phlogiston since only small ashes are left combustion. They equally noticed that metals, in contrast to paper and wood, burn much more slowly in order to form a powder of calx. And because a metal produces more ashes, than say a paper, they concluded that it should contain less phlogiston than say a paper, they concluded that it should contain less phlogiston than wood or paper. The idea of phlogiston being responsible for combustion dominated chemistry for quite a reasonable period of time. It was equally thought that phlogiston was taken from air and stored by plants. A major weakness of this thesis was that at any point in time that metals undergo combustion they gain weight. If their were really an escape of phlogiston the reverse should have been the case. Becher and stahl were aware of this. However they gave an unsatisfactory answer that phlogiston has a negative weight.
Karl W.Scheele (1742-1786) a Swedish apothecary, heated several substance "red calxmercury" and collected the gas which he observed, supported combustion more vigorously than air. He chose to call this gas, "fireair". Before this result was published in 1777. Joseph Priestley an English clergyman and a teacher, independently carried out the same experiment. he named the gas he collected "dephlogisticated air" because the gas he prepared appeared to absorb more phlogiston than ordinary air. Both Sheele and Priestley were able to establish that the gas they discovered occured in air but Scheele it was, especially, who discovered that the component of air they had in this gas explains the combustion which did not involve phlogiston part of the problems could be that; established ideas are not easily dispensed with even when there might be better and more viable theories. It was this kind of incident that led Rene Descartes to rely on his own reason, not on authority.
In France, Antoine Lavoister (1743-1794) was pre-occupid with studying the effect of heat on many substances. His pattern of research was quite different from those of his contemporaries. He weighed the substances he was heating before and after combustion. He was therefore able to establish that heating a metal in vessel open to the air produced an ash that weighed more than the starting metal. If the heating of the metal is carried out with air in a scaled vessel the ash formed, but the total weight of the vessel did not change. As the vessel is opened, air rushed in and the total weight increase. Irrespective of the size of the vessel Lavoisier made use of; the weight gained was the same as the difference between the weight of the weight gained was the same as the difference between the weight of the metal and the weight of the ash formed. By 1774, it was obvious to Lavoisier that the burning substance combined with an element in the air. Priestley visited him in october of that year and told him of his own findings. On repeating Priestly's experience, Lavoisier thus concluded that the new gas was the component of air that combined with substances undergoing combustion.
He named this gas 'Oxygen', a name which was formed from Greek words "acid formed" The name, 'acid' is important given that he thought that oxygen was an essential component of all acids. It was later on proved, nonetheless that hydrogen and not oxygen was the essential component of acid since some acide do not contain oxygen. Thus acid is any substance having in its molecule a hydrogen atom, (Graham and Murray, 1974-94). Against this background. hydrogen is found in every acid.
The stage was then set for a chemical resolution as more gases such as carbon dioxide discovered by Joseph Black and Sir Henry Cavendish and nitrogen and hydrogen by Cavendish were added to the list to the afore-discovered ones.
Method in chemistry.
In chemistry much is spoken about testing and it corresponding reaction. A lot of care is required in testing in chemistry. A Chemist is required to understand the results of his experiments and the experiments of others. There is also the need for one to abhor prejudice. Lavoister for instance, in his experiment on combustion "was not prejudiced by preconceived notions of what result he should obtain"(Miller, 1981:168).
This is in consonance with scientific method-where you allow things to be as they are without any preconception.
A typical experiment in Chemistry to determine its method is the determination of the amount of oxygen in water (about 2cm).
(A) Apparatuses:
(i) Water sample
(ii) Solution of manganous chloride.
(iii)Sodium Hydroxide containing Potassium iodide.
(iv) Solution of sodium thiosulphate (v) Burette
(Vi) Pipette
(vii)Chemical flask.
(B) Test:
We have to collect water with water sampler. A solution of manganous chloride is added to the water, after which a solution of sodium hydroxide containing potassium oxide is equally added. The solution is then acidified with hydrochloric acid. Having done this, the iodine liberated is to be titrated against a standard solution of sodium tioxyphate using starch as indicator.
Observation and Conclusion: The result from the titration will show the amount of oxygen in the water as the reading in the burette will definitely indicate. Two moles of hydrogen molecules will be released for every mole of oxygen molecules produced" (Holderness & Lamber, 1961:168).
A Comparative Appraisal of the Sciences
Some differences could be dicerned between astronomy, physical sciences (physics and chemistry) and biology in respect to subject matter. The focus of astronomy is on celestial Subjects, especially the sun, the moon and the planets; it aims to establish their roles in the scheme of things. Thus, the point of emphasis for astronomers remains the skies.
Like chemistry, physics is primarily interested in non - Living matter. The major difference between physics and chemistry is that while the former focuses on matter in relation to energy the latter emphasizes the action of one kind of substance on another. Biology, on the other hand, differs from the physical sciences as its central area of concern is living things. Overall, we can see a common link between the sciences in terms of subject matter. We shall evaluate this as the work progresses.
In method, there is a common identity between biology, physics and chemistry. In the experiment conducted in each of them above, we observed that all of them shared the following procedure in common: collection of apparatus, test, observation and conclusion. And before the commencement of the experiments, we stated clearly the possible problems and expected results.
For instance, we were able to authenticate that copper is a better conductor of heat than wood. In none of the experiments did our conclusion derive from this that were not observed. Besides all the materials used both chemical and physical constituents were observed to be operational within human system and equally susceptible to human control.
Nonetheless the difference identifiable between biology on the one hand and physics and chemistry on the other is that in the latter, some substances used, such as the flow of current and oxygen, could not be seen with naked eyes. This informed the need for measurement to determine the quantity of oxygen liberated from water and the use of volt meter and meter to take the readings of current. In biology