History and Philosophy of Science

General Studies Unit Kaduna State University, Kaduna Kaduna State, Nigeria GST 203 HISTORY AND PHILOSOPHY OF SCIENCE LECTURE NOTES COURSE INTRODUCTION:
This course is designed with the objectives of not only educating students on the historical developments that have taken place in the fields of science and technology and the philosophical basis on which achievements were made but to stimulate discuss and interests in the minds of students irrespective of the course they offer in the University, it is understood that cross disciplinary exposures of students in this manner will enable them appreciate the need to think alike and work together especially that they are our future leaders.
The end result is lifting our country to joining the elite nations of scientific and technologically developed societies. Man, His Origin and Nature Introduction The origin of man is based on the modern theory concerning the evolution of man which proposes that humans and apes derive from an apelike ancestor that lived on earth a few million years ago. The theory states that man, through a combination of environmental and genetic factors, emerged as a species to produce the variety of ethnicities seen today, while modern apes evolved on a separate evolutionary pathway.

Perhaps the most famous proponent of evolutionary theory is Charles Darwin (1809-82) who authored The Origin of Species (1859) to describe his theory of evolution. It was based largely on observations which he made during his 5-year voyage around the world aboard the HMS Beagle (1831-36). Since then, mankind’s origin has generally been explained from an evolutionary perspective. Moreover, the theory of man’s evolution has been and continues to be modified as new findings are discovered, revisions to the theory are adopted, and earlier concepts proven incorrect are discarded.
Evolution of Man – Concepts in Evolutionary Theory` The currently-accepted theory of the evolution of man rests on three major principles. These principles hinge on the innate ability which all creatures have to pass on their genetic information to their offspring through the reproductive process. An alternative explanation for homology is a common designer. According to this reasoning, the similarities in anatomical features between species point to a blueprint used by a Creator/Designer. The first tenet is microevolution, the occurrence and build-up of mutations in the genetic sequence of an organism.
Mutations are predominantly random and can occur naturally through errors in the reproductive process or through environmental impacts such as chemicals or radiation. The second tenet of evolution is natural selection. Natural selection is a natural mechanism by which the fittest members of a species survive to pass on their genetic information, while the weakest are eliminated (die off) because they are unable to compete in the wild. Natural selection is often termed “survival of the fittest” or “elimination of the weakest. The third tenet is speciation, which occurs when members of a species mutate to the point where they are no longer able to breed with other members of the same species. The new population becomes a reproductively isolated community that is unable to breed with its former community. Through speciation, the genes of the new population become isolated from the previous group. Evolution of Man – Scientific Evidence The theory of evolution of man is supported by a set of independent observations within the fields of anthropology, paleontology, and molecular biology.
Collectively, they depict life branching out from a common ancestor through gradual genetic changes over millions of years, commonly known as the “tree of life. ” Although accepted in mainstream science as altogether factual and experimentally proven, a closer examination of the evidences reveal some inaccuracies and reasonable alternative explanations. This causes a growing number of scientists to dissent from the Darwinian theory of evolution for its inability to satisfactorily explain the origin of man.
One of the major evidences for the evolution of man is homology, that is, the similarity of either anatomical or genetic features between species. For instance, the resemblance in the skeleton structure of apes and humans has been correlated to the homologous genetic sequences within each species as strong evidence for common ancestry. This argument contains the major assumption that similarity equals relatedness. In other words, the more alike two species appear the more closely they are related to one another. This is known to be a poor assumption.
Two species can have homologous anatomy even though they are not related in any way. This is called “convergence” in evolutionary terms. It is now known that homologous features can be generated from entirely different gene segments within different unrelated species. The reality of convergence implies that anatomical features arise because of the need for specific functionality, which is a serious blow to the concept of homology and ancestry. Additionally, the evolution of man from ape-like ancestors is often argued on the grounds of comparative anatomy within the fossil record.
Yet, the fossil record indicates more stability in the forms of species than slow or even drastic changes, which would indicate intermediate stages between modern species. The “missing links” are missing. And unfortunately, the field of paleoanthropology has been riddled with fraudulent claims of finding the missing link between humans and primates, to the extent that fragments of human skeletons have been combined with other species such as pigs and apes and passed off as legitimate. Although genetic variability is seen across all peoples, the process of natural selection leading to speciation is disputed.
Research challenging the accepted paradigm continues to surface raising significant questions about the certainty of evolution as the origin of man. Evolution of Man – The Scrutiny The theory concerning the evolution of man is under increased scrutiny due to the persistence of gaps in the fossil record, the inability to demonstrate “life-or-death” determining advantageous genetic mutations, and the lack of experiments or observations to truly confirm the evidence for speciation. Overall, the evolution of man pervades as the accepted paradigm on the origin of man within the scientific community.
This is not because it has been proven scientifically, but because alternative viewpoints bring with them metaphysical implications which go against the modern naturalistic paradigm. Nevertheless, a closer examination of the evidence reveals evolution to be increasingly less scientific and more reliant upon beliefs, not proof. Darwin’s Theory of Evolution – The Premise Darwin’s Theory of Evolution is the widely held notion that all life is related and has descended from a common ancestor: the birds and the bananas, the fishes and the flowers — all related.
Darwin’s general theory presumes the development of life from non-life and stresses a purely naturalistic (undirected) “descent with modification”. That is, complex creatures evolve from more simplistic ancestors naturally over time. In a nutshell, as random genetic mutations occur within an organism’s genetic code, the beneficial mutations are preserved because they aid survival — a process known as “natural selection. ” These beneficial mutations are passed on to the next generation.
Over time, beneficial mutations accumulate and the result is an entirely different organism (not just a variation of the original, but an entirely different creature). Darwin’s Theory of Evolution – Natural Selection While Darwin’s Theory of Evolution is a relatively young archetype, the evolutionary worldview itself is as old as antiquity. Ancient Greek philosophers such as Anaximander postulated the development of life from non-life and the evolutionary descent of man from animal. Charles Darwin simply brought something new to the old philosophy — a plausible mechanism called “natural selection. Natural selection acts to preserve and accumulate minor advantageous genetic mutations. Suppose a member of a species developed a functional advantage (it grew wings and learned to fly). Its offspring would inherit that advantage and pass it on to their offspring. The inferior (disadvantaged) members of the same species would gradually die out, leaving only the superior (advantaged) members of the species. Natural selection is the preservation of a functional advantage that enables a species to compete better in the wild. Natural selection is the naturalistic equivalent to domestic breeding.
Over the centuries, human breeders have produced dramatic changes in domestic animal populations by selecting individuals to breed. Breeders eliminate undesirable traits gradually over time. Similarly, natural selection eliminates inferior species gradually over time. Darwin’s Theory of Evolution – Slowly But Surely… Darwin’s Theory of Evolution is a slow gradual process. Darwin wrote, “…Natural selection acts only by taking advantage of slight successive variations; she can never take a great and sudden leap, but must advance by short and sure, though slow steps. Thus, Darwin conceded that, “If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down. ” Such a complex organ would be known as an “irreducibly complex system”. An irreducibly complex system is one composed of multiple parts, all of which are necessary for the system to function. If even one part is missing, the entire system will fail to function. Every individual part is integral. Thus, such a system could not have evolved slowly, piece by piece.
The common mousetrap is an everyday non-biological example of irreducible complexity. It is composed of five basic parts: a catch (to hold the bait), a powerful spring, a thin rod called “the hammer,” a holding bar to secure the hammer in place, and a platform to mount the trap. If any one of these parts is missing, the mechanism will not work. Each individual part is integral. The mousetrap is irreducibly complex. Darwin’s Theory of Evolution – A Theory in Crisis Darwin’s Theory of Evolution is a theory in crisis in light of the tremendous advances we’ve made in molecular biology, biochemistry and genetics over the past fifty years.
We now know that there are in fact tens of thousands of irreducibly complex systems on the cellular level. Specified complexity pervades the microscopic biological world. Molecular biologist Michael Denton wrote, “Although the tiniest bacterial cells are incredibly small, weighing less than 10-12 grams, each is in effect a veritable micro-miniaturized factory containing thousands of exquisitely designed pieces of intricate molecular machinery, made up altogether of one hundred thousand million atoms, far more complicated than any machinery built by man and absolutely without parallel in the non-living world. And we don’t need a microscope to observe irreducible complexity. The eye, the ear and the heart are all examples of irreducible complexity, though they were not recognized as such in Darwin’s day. Nevertheless, Darwin confessed, “To suppose that the eye with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection seems, absurd in the highest degree. However, despite all of its weaknesses and often unscientific character, human evolution will doubtless continue to be the most popular story in the evolutionary legend, and the cast of apes considered to be ancestral to man will continue to change, as it has in the past, but that is not important to evolutionism as long as the central “dogma” and its profound implications remains – man is a beast. Human Nature Human nature refers to the distinguishing characteristics, including ways of thinking, feeling and acting that humans tend to have naturally.
The questions of what these characteristics are, what causes them and how this causation works, and how fixed human nature is, are amongst the oldest and most important questions in western philosophy. These questions have particularly important implications in ethics, politics and theology. This is partly because human nature can be regarded as both a source of norms of conduct or ways of life, as well as presenting obstacles or constraints on living a good life.
The complex implications of such questions are also dealt with in art and literature, while the multiple branches of the Humanities together form an important domain of inquiry into human nature, and the question of what it means to be human. The branches of contemporary science associated with the study of human nature include anthropology, sociology, sociobiology and psychology, particularly evolutionary psychology and developmental psychology. The so-called “nature versus nurture” debate is a broadly inclusive and well-known instance of a discussion about human nature in the natural sciences.
Man and His Cosmic Environment: We are connected to the cosmic nature through the proximity and the presence of our local star which we know as the sun (sol). Completely dominating the generation of life within the terrestrial environment in which we all have co-evolved; the sun has nine planets in orbit about itself, collectively known as the solar system. Our home, the Earth, is the third planet after Mercury and Venus. Beyond the Earth is Mars, then the asteroid belt, then the outer planets of Jupiter, Saturn, Uranus, Neptune and lastly Pluto.
The sun is a huge cosmic fire which spends its fuel of hydrogen by way of nuclear processes, to generate huge amounts of energy which is continually radiated out and away from the sun’s surface, and across the expanse of the solar system, out into the inter-stellar spaces. It is the systematic of three celestial bodies, the Sun, Earth and the Moon, which have defined and continue to define the specifications of the chariot which bears our life through the greater way of the cosmos.
It is our relativity to these three bodies that has given rise to the human conception of both time and space in the cosmic environment. The terrestrial environment in which we dwell on a day to day basis is a subset of the greater cosmic environment. Earth Solar system Milky Way Galaxy Universe| Stars are found clustered together in galaxies, and galaxies in galactic clusters. There seems to be no observable end to the cosmos. For example, it is estimated that our galaxy, the Milky Way, contains about 200 billion stars.
It is further estimated that there are over 100 billion galaxies in the universe. The cosmos is thus observed to be an ocean of light, fed by the tributary streams of stars and galaxies. A vast and deep cosmic ocean of light, in which our planet, Earth is just an isolated and remote terrestrial island. Light travels at a speed of about 300,000km per second, capable of circulating about the Earth 712 times in one second. It takes about 8 minutes for light to reach us from the Sun, over four years from the nearest star and 400,000 years from the nearest galaxy.
Because of this huge vastness of the cosmos, one common unit of measurement of cosmic distance is the light-year, which represents the distance which light travels in one Earth year. The nearest galaxies to the Milky Way are the large and small Magellanic Clouds which are located at some 150,000 light-years distance. The brightest of the closest galaxies is the Andromeda Nebula, which are 2,000,000 light-years away. The stars which we see in the night sky may be stars within the Milky Way, but they may also be remote galaxies, or even remoter galactic clusters.
The Earth is estimated to be 412 billion years old while the sun is estimated to be about 5 billion years old. The supply of Sun’s fuel of Hydrogen is estimated to last another 5 billion years. Scientific Methodology: Science: (From the Latin Scientia, means “knowledge”) is a reliable body of knowledge that can be logically and rationally explained. Scientific method: refers to a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge.
Philosophies fall into two primary categories namely: 1. Idealism and 2. Materialism. The basic proposition of these two categories pertains to the nature of reality, while to the idealist, spirit or mind is primary, and created matter is secondary. The materialistic philosophers believe that matter is primary and mind or spirit is secondary. The theory holds that the only thing that exists is matter and that all things are composed of material and all phenomena (including consciousness) are the result of material interaction.
Scientific method agrees with the materialistic philosophy where all scientific discoveries arise from human interaction with nature. This method of discovery is characterized by a sequence of steps, although these steps or procedures may vary from one field of inquiry to another, the general identifiable features that form the major steps in scientific method include: Observation, Problem definition, Hypothesis formulation, Experimentation, Conclusion and Theory formulation. 1. Observation: This is the first step in scientific method.
It is either an activity of living being (such as human), consisting of receiving knowledge of the outside world through the senses, or the recording of data using scientific instruments. Observations that are made using the senses are said to be direct observation, while indirect observation is a situation where data are recorded using scientific instruments. In science, anything that cannot be observed cannot be investigated scientifically. For instance, it is easy to observe that when a stone is thrown up, it must always come down.
Also, someone can observe plant growing in the dark produced pale yellow color instead of the normal green. Observations can be classified into two: (a)Spontaneous or passive observation: These are unexpected observations which arise from impulse or inclination, rather than from planning or response to situations. This type of observation begins with one noticing an object or event. Observation can only be meaningful if observer either consciously or unconsciously relates observations with relevant knowledge. (b)Induced or active observation: These are deliberate or intentional observations.
In this case, the researcher carefully plans on how to study an object, a process, an event or response to a situation. Scientific observation can be enhanced by developing the habit of watching things with an active enquiring mind. A good observation comes after so many errors and corrections; more so, it should be observed independently by other scientist and report the same thing. 2. Problem definition: After an observation has been made, the hypothetical student becomes curious, for instance, he will decide to find out why a stone always comes down when thrown up.
To be able to define a problem, questions must be asked. Just like good observation, to be of value to science a good question must be relevant and it must be testable. 3. Hypothesis: Once questions have been raised over a certain phenomenon, a good scientist then guesses what the answer to the question might be. This assumed answer is called a hypothesis. A hypothesis is a suggested explanation of a phenomenon or alternatively a reasoned proposal suggesting a possible correlation between or among a set of phenomena. Normally hypotheses have the form of a mathematical model.
Sometimes, but not always, they can also be formulated as existential statements, stating that some particular instance of the phenomenon being studied has some characteristics and causal explanations, which have the general form of universal statements, stating that every instance of the phenomenon has a particular characteristics. Not all hypotheses relating to a particular problem are valid. The only way to decide which hypothesis is correct or valid is to test each of the hypotheses. This is where scientific experiments are important.
The outcome of the experiment could lead to; i. Acceptance of the hypothesis ii. Modification of the hypothesis or iii. Rejection of the hypothesis. Once a hypothesis is modified or new once formulated, they must be tested afresh for validity by performing new experiments. Clearly, the guessing and guess testing might go on for years and a right answer might never be found. Much faster progress would be made if the number of hypotheses were few. The amount of previous knowledge a scientist has, enables him to achieve this. 4. Experimentation:
This is a technique for dealing with observational errors whereby a deliberate controlled of some properties (factors or variables) under different conditions is applied to see what varies or what remain the same. Once guesses are made, they can be tested by experiments. If test results contradict predictions, then hypotheses are called to question and explanations may be sought. Sometimes experiments are conducted incorrectly and are at fault. If the results confirm predictions, then the hypotheses are considered likely to be correct but might still be wrong are subject to further testing. . Conclusion: They are reached after analyses of experimental results are made . Conclusions may sometimes include in clear terms the acceptance or rejection of a hypothesis. The hypothesis can also be redefined, modified and clarified when the situation arises. Some other conclusions may even be overthrown and discarded. For example, if after a controlled experiment involving only one variable, one may conclude that the other factors beside the one varied may be responsible for the observed problem/phenomenon. 6. Theory Formulation:
A scientific theory comprises a collection of concepts, including abstractions of observable phenomena expressed as quantifiable properties, together with rules (called scientific laws) that express relationships between observations of such concepts. A scientific theory is constructed to conform to available empirical data about such observations, and is put forth as a principle or body of principles for explaining a class of phenomena. A theory is usually proposed when a hypothesis has been supported by really convincing evidence. This evidence must be obtainable in many different laboratories and by many researchers.
Theories are open to tests, revisions, and tentative acceptance or rejection. As soon as new information is observed in the course of applying the theory, such existing or established theory is revised. Application of scientific method: Whether the scientific method can legitimately and fruitfully be used in the social sciences, Art, and in the socio-natural or hybrid sciences such as psychology and linguistics, has been a subject of controversy. The history of these sciences shows conclusively that the scientific method has been fruitful whenever it has actually been employed.
For the pure sciences, the use of the scientific method stands out as a major characteristic aspect of their researches; its absence, therefore, is a sure indicator of non-science. In other words, a discipline where the scientific method plays no role is not a science. Thus, such field as theology, literacy criticism, psychoanalysis, homeopathy, graphology, and palmistry can hardly be regarded as scientific. Application: Scientific method can be applied in real life situation as well as in scientific discoveries. Creative and Critical Thinking:
Decision making is part of our daily activities and the quality of our decision could affect our lives and sometimes the lives of other people. For instance, imagine a cook in a restaurant who in trying to add salt to soup, pick a bottle containing cyanide instead; or when quality control officers in a flour company or a water board for instance, fail to take good decision. Many lives could be affected. The quality of our day to day decision depends to a great extent on the quality/procedure of our thinking. Effective thinking procedure consists basically of: . Creative thinking: is the type of thinking that is patterned towards formation of possible solution of problem or possible explanations of a phenomenon. 2. Critical thinking: is a purposeful reflective judgment concerning what to believe or what to do. Critical thinking calls for the ability to: •Recognize problems, to find workable means for meeting those problems •Understand the importance of prioritization and order of precedence in problem solving •Gather and marshal pertinent (relevant) information •Recognize unstated assumptions and values Comprehend and use language with accuracy, clarity, and discernment •Interpret data, to appraise evidence and evaluate arguments •Recognize the existence (or non-existence) of logical relationships between propositions •Draw warranted conclusions and generalizations •Put to test the conclusions and generalizations at which one arrives •Reconstruct one’s patterns of beliefs on the basis of wider experience •Render accurate judgments about specific things and qualities in everyday life Note: That an effective thinking must be creative as well as critical.
Thus, an effective thinker (good scientist) must be able to create solution and criticize existing ones. The six steps of scientific methods actually cover these types of thinking; if one is to have real assurance that his/her final decision is sound, then all phases/steps must be completed. Effective thinking requires practice if it must be mastered. The amount of success one gets in effective thinking depends on how objective one is in viewing things (he/ she and the world) without bias.
Willingness to concentrate on the pursuit of truth, taking up all problems and openness to one’s feelings is essential tools for objectivity. For the later, one must be able to discern when one’s feelings are relevant or not. Science and Technology in the Society and Service of Man: Science: This is an institution, a method or process of acquiring knowledge. It is the study of the physical and natural world and phenomenon, especially by using systematic observation and experiment. It is a systematically organized body of knowledge about a particular subject e. g. Chemistry, Physics etc. It is omething studied or performed methodically; an activity that is the object of careful study or that is carried out according to a developed method. Science is both the process and product of investigation and research. Technology: Technology is defined as the application of scientific knowledge and research, with the aim of developing products or processes for the use of man. It consists of the practical knowledge of what can be done and how. It is not a body of theoretically related laws and principles. It is characterized by the techniques, devices, procedures, processes and materials.
It is more of a collection of practical information that can be used to do something. Example: From agriculture, say a large crop of vegetables is in danger of destruction by insects, and agricultural scientists have already developed insecticides to be used to fight the insects. If a decision is taken to spray the insecticides from an airplane, that decision is made by an agricultural engineer. He will put economic and environmental factors into consideration in making the decision. All the techniques, procedures and materials used make up the technology of insecticides spraying from an airplane.
It is important to note that in spite of the seeming difference between science and technology, they are intimately linked, or symbiotic. This is because technology will be crippled and blinded, if not for the new knowledge which science provides it. Science on the other hand will not progress much, if technology does not supply it with new instruments, new techniques and new power. For example the practice of photography (technology) originated before the theory of photographic process was formulated (science). Photographic materials were made by trial and error.
Up till about 1950’s, the methods used in manufacturing photographic materials were a little advanced than the basic science of the photographic process. A point was reached however, when progress in photography became slow. Progress was only accelerated when the physical chemistry underlying photography process was understood. X-rays were discovered through scientific research. The knowledge of theses x-rays machines. These x-ray machines, in turn now help scientific researchers to examine, for example the arrangement of atoms in crystals. So both science and technology go hand in hand. What Motivates Scientist and Technologists?
What drives the scientist when he is acting as a scientist is the longing to know and understand. The key word here is curiosity. The scientist is curious to know and understand nature. He is not bothered about application of his knowledge. Other spirits of inquiry includes: 1. A questioning of all things 2. A search for data and relations that give meaning 3. A demand for verification 4. A respect for logic (sensible rational thought and argument rather than ideas that are influenced by emotion) What drives the technologist on the other hand is the desire to translate ideas and plans into concrete products or processes.
The key word is know-how. His/ Her aim is to produce things and not to formulate theories about the devices and the techniques used in the process. It is important to note that the ideas implemented by the technologist are derived both from science and non-science areas. The corresponding plans are often developed by engineers. The Beginning and Importance of Technology in Human Affairs: In his desire to provide for his basic needs of food, clothing and shelter, he made and used tools (origin of technology). With time, man not only sought to satisfy his needs but also his wants.
Technology also helped man to get what he wanted. These include play, leisure, houses, travelling, exotic foods, faster communication with others etc. Technology is as old as man himself. Man’s earliest tools were his hands and teeth. He graduated to stones, and then to sticks shaped to be used as tools. As time goes on, he developed tools of special types to be used for hunting, fishing and the making of clothes and shelters. Man’s technical progress is believed to be governed by two elements, which are: 1. Discovery 2. Invention A discovery is a new way of looking at an old phenomenon.
Invention however, is defined as a mental process in which various discoveries and observations are combined and guided by experience into some new tool or operation. It is important to note that much experience is needed to lead to truly important inventions. The next stage in the evolution of technology is the discovery of fire. It is the most important discovery of Stone Age man. He used the fire to warm himself and to prepare tastier food. Fire then led to the birth of cooking and subsequently to the invention of suitable kitchen utensils and cooking methods such as baking, frying, steaming etc. Can you imagine what it’s like to eat uncooked food? ) The discovery of fire was therefore a very important event. Man later began to cultivate his own crops and rear animals for a more regular supply of food. This led to the establishment of communities. He domesticated animals and developed agricultural tools. He made textiles, produced pottery, invented the wheel and the sail to improve his transportation. Man also learned to mine and utilize metals such as copper and iron. The Importance of Science, Technology and Inventions:
The factors that distinguish our age (20th century upwards) from the past are: 1. The recognition of the importance of science and technology in human affairs 2. The increased pace of scientific and technological development (which makes it part and parcel of our daily living) and 3. The realization that science and technology are not simply a limited or local factor. It encompasses all men everywhere, and is interrelated with nearly all human endeavors. The 20th century has been characterized by rapid advances in science, technology and inventions.
We all feel the impact of them in our daily lives as well as in our social and political institutions. For instance, modern man has replaced the implements and tools of primitive man with tractors and ploughs for tilling the soil. This represents a higher level of technology. The hydrogen bomb, nuclear weapons/ missiles have replaced the bow and arrow technologies of the old eras. Even on the home front, housekeeping has been happily made easier for the housewives with the introduction of labor saving machines such as microwave and electric ovens, vacuum cleaners etc.
Without doubt, the standard of living of a nation depends on science, technology and inventions. Developing nations such as Nigeria are beginning to realize one essential difference between them and the so-called developed nations. This is because of the fact that these developed nations have been able to create, master and use modern science and technology. This means that science, technology and invention form the foundation of modern existence. A highly developed education and research programs in the basic sciences are needed by any country that would want a secure and stable society.
Knowledge of the basic sciences such as Physics, Biology and Chemistry are of indispensable value because it is through their research efforts that technological growth can take place. The stable society should be one where industrialization, public health care, advanced agriculture etc. can flourish. Long-term progress is only possible if a percentage of government funds are used for teaching and research. Renewable and Non-renewable Resources, Man and His Energy Environment: Energy: Energy can be defined as follows: 1. Energy is the strength and vitality needed to do vigorous activity 2.
Energy is the ability of matter or radiation to do work Energy can be derived from physical resources to provide light, heat, current, voltage etc. Energy Sources: There are five ultimate sources of energy namely: 1. Sun 2. Motion and the gravitation potential of the sun, the moon and the earth. 3. Geothermal energy from cooling, chemical reactions and radioactive decay in the earth. 4. Nuclear reaction 5. Chemical reactions Among all these, energy sources can be grouped into two, namely: 1. Renewable and 2. Non-renewable energy resources
Renewable energies are derived from sources 1, 2, 3 and 4, while non-renewable energies are derived from 1, 3, 4 and 5. Renewable Energy (Infinite Energy): This is energy obtained from continuous and repetitive current of energy occurring in the natural environment as a current or flow irrespective of there been a man-made device to intercept or harness the power. These energy resources are infinite and inexhaustible and their development requires investment in sophisticated technologies. Example of renewable energy resources are: 1. Wood and biomass: – Energy from trees and plants (e. . corn, can be converted to alcohol and ethanol, cassava to ethanol etc. ) 2. Hydroelectric power: – Energy from water (Though to an extent not regarded as renewable resources. ) 3. Solar energy: – Energy from the Sun. 4. Wave energy: – Energy due to movement of ocean waters. 5. Tidal energy: – Energy from rise and fall of sea waters. 6. Fission nuclear energy: – Energy due to splitting of atoms. 7. Fusion nuclear energy: – Energy due to combining atoms. 8. Wind energy: – Energy due to air movement. 9. Geothermal energy: – Thermal energy from earth’s core etc.
Non-Renewable Energy (Finite Energy): This is obtained from static/ stationary store of energy that remains bound unless released by human interaction e. g. nuclear fuel (Uranium), fossil fuel of coal, oil and natural gases. Note that the energy is initially an isolated potential and external action is required to initiate the supply of energy for practical purposes. These energy resources have limited life p, and also called exhaustible energy resources. Examples of non-renewable energy resources are: 1. Coal: – is a combustible sedimentary rock formed from the remains of plant life. 2.
Petroleum energy: – Energy formed by decomposition of living matter mainly from marine organisms. 3. Natural gas: – Crude oil in reservoirs is always accomplished by a mixture of gas called natural gas. The principal component is methane CH4 about 85-95%. The remainder is mainly composed of ethane, propane and butane (hydrocarbons). 4. Shale oil: – Energy from solid or semi-solid of petroleum and natural gas. Shale oil cannot be recovered by conventional methods of petroleum production. They are sometimes referred to as oil or tar sand. 5. Peat: – A shaped block dug from a bog and dried for fuel.
Uranium (U-235, U-236, U-238): – Is a common constituent of continental rock with an average crystal concentration of about 2 parts per million (2ppm). Concentration of Ore quality is generally in 2000-10,000ppm range i. e 0. 5-1. 0%. Fossil Fuels: – Encompasses coals, oil, natural gas, petroleum, shale oil etc. Energy Production and Environmental Damage: 1. Hydroelectric Power: – is widely utilized world-wide. It is a clean energy source but has certain disadvantages such as: * Destruction of natural vegetation * Destruction of farmlands * It is capital intensive Diverting waters by hydroelectric power displaces population and loss of agricultural farmlands. * Changes of river courses may affect the animal, plant and fish lives. 2. Environmental Impacts of Wind Power: – * Causes local noise pollution and electromagnetic interference. * Wind power is seen by others unsightly (not pleasant to look at), since the windiest sites are in areas of outstanding natural beauty, natural parks, and other scenic sites. 3. Tidal Energy Environmental Impacts: – Besides the high cost of capital, * It weakens fish reproduction. The ability of estuaries (wide tidal river mouth) to support wintering (coldness) and migrating bird’s population could be affected (though this area needs more research). * Tidal barrages can adversely affect migrating and spawning fish population (i. e. deposits of fish, frog’s eggs). 4. Environmental Impacts of Wave Power: – The environmental impacts are minimal; however the reliability of the technology is questionable. 5. Environmental Impacts of Solar Power: – * It is very expensive but environmentally friendly. 6. Environmental Impacts of Geothermal Energy: – Carbon dioxide CO2 and hydrogensulphide HS2 emission may be high (greenhouse gases). * Sinking land above geothermal wells can cause contamination of water by saline and possible toxic water (though these problems can be managed successfully). * Occupies plenty farmlands. 7. Environment Impacts of Biomass: – * Produces greenhouse gases and small amount of chlorofluorocarbons (CFC’s). * Waste disposals problems (Available land for disposals and dangers from the bi-products). 8. Environmental Impacts of Fossil Fuels: – * Open cast mining and piling of waste scar (damage) landscape. Leakages of oil and gas from pipelines and installation also cause environmental pollution problems. * Combustion of fossil fuel can cause acid rain. * Combustion of fossil fuels produce greenhouse gases Acid Rain: It occurs because of the atmospheric continual effort to cleanse itself off various pollutants that are introduced into air. The water droplets in clouds absorb (hold) particulate matter and gas molecules out of the air. Not all such substances are removed by rain or precipitation but instead remain suspended in clouds and moisture. POLLUTION
Pollution is the introduction of contaminants into a natural environment that causes instability, disorder, harm or discomfort to the ecosystem i. e. physical systems or living organisms. Pollution can take the form of chemical substances or energy, such as noise, heat, or light. Pollutants, the elements of pollution, can be foreign substances or energies, or naturally occurring; when naturally occurring, they are considered contaminants when they exceed natural levels. Thus a pollutant can be defined as a waste material that pollutes air, water or soil.
Three factors determine the severity of a pollutant: its chemical nature, the concentration and the persistence. Some pollutants are biodegradable and therefore will not persist in the environment in the long term. However the degradation products of some pollutants are themselves polluting such as the products DDE (dichlorodiphenyldichloroethylene) and DDD (dichlorodiphenyldichloroethane) produced from degradation of DDT (dichlorodiphenyltrichloroethane). Pollution is often classed as point source or non-point source pollution. Point Source Pollution
A point source of pollution is a single identifiable localized source of air, water, thermal, and noise or light pollution. A point source has negligible extent, distinguishing it from other pollution source geometries. The sources are called point sources because in mathematical modeling, they can be approximated as a mathematical point to simplify analysis. Pollution point sources are identical to other physics, engineering, optics and chemistry point sources and include: * Water pollution from an oil refinery wastewater discharge outlet * Noise pollution from a jet engine Disruptive seismic vibration from a localized seismic study * Light pollution from an intrusive street light * Thermal pollution from an industrial process outfall * Radio emissions from an interference-producing electrical device Types of air pollution sources which have finite extent are line sources, area sources and volume sources. Air pollution sources are also often categorized as either stationary or mobile. Non-Point Source Pollution
Non-point source (NPS) pollution is water pollution affecting a water body from diffuse sources, such as polluted runoff from agricultural areas draining into a river, or wind-borne debris blowing out to sea. Nonpoint source pollution can be contrasted with point source pollution, where discharges occur to a body of water at a single location, such as discharges from a chemical factory, urban runoff from a roadway storm drain or from ships at sea. NPS may derive from many different sources with no specific solution to rectify the problem, making it difficult to regulate. Forms of pollution
The major forms of pollution are listed below along with the particular pollutants relevant to each of them: * Air pollution, the release of chemicals and particulates into the atmosphere. Common gaseous air pollutants include carbon monoxide, sulfur dioxide, chlorofluorocarbons (CFCs) and nitrogen oxides produced by industry and motor vehicles. Photochemical ozone and smog are created as nitrogen oxides and hydrocarbons react to sunlight. Particulate matter or fine dust is characterized by their micrometer sizePM10to PM2. 5. * Light pollution, includes light trespass, over-illumination and astronomical interference. Littering * Noise pollution, which encompasses roadway noise, aircraft noise, industrial noise as well as high-intensity sonar. * Soil contamination occurs when chemicals are released by spill or underground leakage. Among the most significant soil contaminants are hydrocarbons, heavy metals, MTBE, herbicides, pesticides and chlorinated hydrocarbons. * Radioactive contamination, resulting from 20th century activities in atomic physics, such as nuclear power generation and nuclear weapons research, manufacture and deployment. (See alpha emitters and actinides in the environment. * Thermal pollution is a temperature change in natural water bodies caused by human influence, such as use of water as coolant in a power plant. * Visual pollution, which can refer to the presence of overhead power lines, motorway billboards, scarred landforms (as from strip mining), open storage of trash or municipal solid waste. * Water pollution, by the release of waste products and contaminants into surface runoff into river drainage systems, leaching into groundwater, liquid spills, wastewater discharges, eutrophication and littering. Sources and Causes
Air pollution comes from both natural and man-made sources. Though globally, man-made pollutants from combustion, construction, mining, agriculture and warfare are increasingly significant in the air pollution equation. Environmental effects of textile wastes and other material: Textiles are types of fabrics made by weaving, or knitting. The principal raw materials used in textile manufacture are the natural fibers and synthetic (man-made) fibers 1. Natural fibers: These include (a) Vegetable fibers e. g. cotton, flax and hemp; (b) Animal fibers e. g. heep’s wool; and (c) Mineral fiber e. g. asbestos 2. Synthetic fibers: (a) They are polymers based on petroleum and cellulose such as nylon Textiles are manufactured to perform a wide range of roles. They are made up of different types of fibers that are mixed in varying proportions. The manufacture of natural textiles involves a wide variety of physical and chemical processes. The processes depend on the fiber type and the specification of the fabric product for use in clothing, furnishings or for industrial applications. Textile wastes and environmental effects: a) Textile wastes originate from both the household (consumer) and the industrial (manufacturing) sectors. (b) Consumer waste comprises wastes dumped in dust bins or that separated for reuse or recycling e. g. unwanted clothing and carpets. (c) Manufacturing waste originates from the processing of raw materials and in the fabrication and production of finished textiles and garments which include cuttings and rejected materials. Textile wastes can be classified thus: 1. Dangerous packaging wastes: These wastes come from the exhaustion of the laboratory chemical reactive. E. g. paper packaging wastes, plastic packaging wastes and metallic packaging wastes. 2. Non-dangerous packaging wastes: These come from the packaging of raw textile material of different types (such as fibers, yarns, fabrics) pieces of paper packaging wastes (such as boxes, bags, cardboard). 3. Non-dangerous wastes: Include textile wastes that are retained on equipment filters, raw materials and fibers, yarn, woven, knitted, cut offs, threads and defective items. Others are sludge for water treatment and also printing toners. 4.
Dangerous wastes: These also include grease and oil impregnated rags, used oils – solvent wastes, fluorescent tubes – batteries (equipment and transport vehicles), chemical wastes, dyes, print pastes. , contaminated textile wastes with chemicals, wastes of electric and electronic equipment (with metals)etc. Environmental Effects: The environmental risks that are associated with the manufacture of clothing are limited with few significant risks. (a) Packaging wastes litter the land and occupy spaces that may be used for other purposes such as agric. b) The cutting and working of material generates significant quantities of small particles of fabric. These are called “fly” in the industries. High levels of fly and dust within buildings cause occupational health hazards (primarily respiratory). If uncontrolled, emissions of fly and dust may cause and nuisance problems outside the building. Lastly, If not properly cleaned, buildup of fly on machines can ignite and cause fires. (c) Textile waste in incinerators: These emit organic substances through incinerator chimneys. Organic substances include dioxins, heavy metals, acidic gases and dust particles.
All these are potentially harmful to both humans and the environment. (d) Textile waste in landfills: * This contributes to the formation of leach- ate as it decomposes. * This has the potential to contaminate both surface and groundwater sources. * Methane gas (a major greenhouse gas, and a significant contributor to global warming) is also formed as a result of decay of textile waste in landfill. However, the gas can be utilized of collected. * Decomposition of organic fibers and yarns such as wool produces large amounts of ammonia and methane.
Ammonia is highly toxic in both terrestrial and aquatic environments. It can be toxic in gaseous form and has the potential to increase nitrogen in drinking water. These have adverse effect on humans. Cellulose-based synthetics decay at a faster rate than chemical-based synthetics. Synthetic chemical fibers can prolong the adverse effects of both leachate and gas production due the length of time it takes for them to decay. Disposal: * Textile waste can be incinerated with other materials to produce energy (bottom fly ash). Bottom ash, can be used for construction purposes. * Fly ash used as a cement replacement. * Use of chrome substitutes such as aluminum, titanium, cod oil * Improved waste water treatment. * Good management environmental practices. Range from staff education and training. * Improving the quality and quantity of chemicals used; * Optimizing use of energy, water consumption etc. CHEMICAL AND RADIOCHEMICAL HAZARDS 1. RADIOACTIVE MATERIALS The need to understand what radiochemical substances are want danger they pose to the end users cannot be over emphasized.
This important view should be embraced by all whether you are in the humanities or in science and technology discipline. Our environment must be kept safe for the benefit of life on our beautiful planet Radiochemical material and associated hazards are not new especially considering when radioactivity was first discovered by Henri Becquerel in 1896. This discovery revolutionized the fields of physics and chemistry as new products and services relating to both the positive and negative uses to which it was put to use.
Radiochemical hazards are generally associated with working with chemical and radioactive substances at any place but usually in the laboratories. The most important negative use to which radioactivity has been put to use was in the production and use of the nuclear bombs (atomic bombs) in Hiroshima and Nagasaki during the Second World War by the Americans. This marked the end of the war. Some of the benefits derived from the application of radioactivity are found in the field of medicine where specialized radiations have been used to treat cancer and tumors.
It is used in x-ray where internal organs are investigated. In science, it has been used to study reaction mechanisms and structural analysis of materials. It is also used in generating electricity from nuclear reactions. These radioactive materials or chemicals have some health hazards associated with their usage, for example, the inventor of the word “radioactivity” Marie Curie died from a disease of the bone marrow as a result of her long term exposure to radioactive materials in 1934 at age 66.
You will recall the Chernobyl nuclear reactor accident in which many people died and several others were exposed to very high doses of radiations. Recently also, Japan woke up with a Tsunami that defercited the country their by damaging four of their nuclear reactors at Fukushima resulting in the death of many people and releasing very dangerous radiations to the environment which further poses serious health risk to life. Radioactive chemicals can render people impotent or result in the birth of medically handicapped children.
Let us take a pause and define some basic concepts in radiation chemistry/physics. 2. DEFINITIONS OF SOME TECHNICAL TERMS * Radioactive: – Describes a substance such as uranium or plutonium that emits energy in the form of streams of particles, owing to the decaying of its unstable atoms. This energy can be damaging or fatal to the health of people exposed to it. * Hazardous: – Potentially very dangerous to living beings or the environment. * Radiotoxic: – Of toxic effect of radiation-relating to the toxic effects of radiation of radio-active substances. Radioactivity: – The breakdown of heavy atom into simple ones. * Radioactive substances (chemicals): – These are substances which are regarded as sources of ionizing radiations which may be either sealed or unsealed. Sealed sources (small) consist of radioactive materials permanently enclosed in containers e. g. Radium needles (226Ra), Radio cobalt needles (60Co), Radio gold (198Au), Radon seeds (222R), Radio tantalum (182Ta), Radio trium (90Y), Caesium needles (137Ce), Radio strontium plaques (90St). Large sealed sources for radiotherapy are normally charged with Cobalt 60 or Caesium 137. Chemical hazard: – Chemical hazard is the danger caused by chemicals to the environment and people. A chemical hazard arises from contamination with harmful or potentially harmful chemicals. Please take note of the following; * Toxic chemicals * Hazardous wastes * Hazardous chemicals * Radiochemistry: – Branch of chemistry that deals with radioactive elements and their applications. * Radiology: – The branch of medicine that deals with the use of X-rays and radioactive substances such as radium the diagnosis and treatment of diseases. The science of radiation and radioactive substances and their application e. g. n structural analysis. * Hazardous wastes: – These are toxic byproducts of various processes, a byproduct of manufacturing processes or nuclear processing that is toxic and presents a potential treat to people and the environment. * Radioactive wastes: – Used radioactive materials waste. Material that is radioactive, particularly the waste from nuclear reactors and medical treatment and research. * Radioactive series: – Series of atom types; a series of related atom types nuclides of radioactive isotopes, each of which is transformed into the next by emission of an elementary particle until a stable nuclei is obtained.
There are three (3) such substances, the thorium, the uranium and the actinium and almost all naturally occurring radioactive isotopes belonging to one of them. 3. NATURAL SOURCES OF RADIATION The heavy radioactive elements found in nature are members of three different series of elements beginning with uranium, thorium and actinium. Since the 1970s, concern has grown over exposure of individuals to radon in homes and other buildings. Because radon is a gas, it can percolate from uranium bearing rocks, subsoil, or building materials into the air within a building.
Radon itself is not a health threat because it is an un-reactive noble gas. It enters and exits the beings without remaining in the body. However, its decay product, polonium, from the oxygen family, is more reactive. Polonium can adhere to dust particles in the air that can become trapped in the lungs. Being an ? (alpha) emitter, polonium and its decay products are potentially cancer causing agents. As is always the case, evaluating the seriousness of the health threat from such a substance in the environment is difficult. 4. SOURCES OF RADIATIONS * Buildings/paint * Sun Nuclear plants * X-ray units in hospital (radiology dept) * Electronic gadgets * Contaminated air * Irradiated foods (as preservatives) * In research laboratories. (List more) 5. RADIATION AND MATTER During the decay of radioactive nuclide, mass is lost and energy is released. The nuclei and particles collide with the atoms and molecules of the surroundings. In this process valence electrons may be knocked of atoms and molecules to produce ions or pulled up to form or breakdown bonds. The end products are electromagnetic radiations (x-ray, ? -rays, ? -rays, ? -rays, neutrons etc. re formed. ) * Alpha rays (or ? -rays particles): -are of limited interest in diagnosis and therapy because they lack penetration, even when emitted at high energy. They have a high ionizing power. 24He=alpha ray, it is a+ve particle They are stopped by a sheet of paper or by the dead layer of the skin. However, if ? emitting radionuclide’s enter the body (by ingestion or in halation or through open wounds) the alpha rays may cause serious injuries. * Beta rays (or ? -ray particles): -The rays are negatively charged particles of high penetrating power and high velocity.
They are deflected toward the positive part of magnetic field. They are used medically for the treatment of superficial lesions. * Gamma rays (? -rays): – Like x-rays, are electromagnetic radiation. Unsealed gamma emitting sources are widely used in nuclear medicine for diagnosis and therapy; they have extremely high penetrating power, then ? and ? rays. The ray is very dangerous to living creatures because they can cause damage to the living tissues. 6. MANAGEMENT OF HAZARDOUS RADIOCHEMICALS As has been discussed earlier, radiochemical have found a lot beneficial uses to man.
But the major problem is how to handle them in such a way that they do not cause danger health problems to man. In the light of these, all necessary protective measures must be put in place to protect the users ’e . g; * All workers in nuclear sites or radiologists must wear protective materials, and such plants must be highly secured to minimize chances of accidents or over exposures. * The handling of nuclear wastes must be such that both short and long term dangers associated with the disposal are taken into consideration.
For example, nuclear waste should not be dumped in the sea as exposure to life under the sea will definitely affect man (consumer). Also, burying them under the ground has its dangers, as the shifting of the earth crust could make these waste come in contact with major sources of water and thus will affect life. * Radioactive liquids should not be poured into sinks but into designated containers. Also radioactive waste cans’ for adequate disposal by burial * At the close of day; all parts of the body, including clothing should be thoroughly monitored.
This is best done by wearing radioactive dictators like the pocket Dosimeter or any other pocket ionization chamber * Cosmetics should never be applied on the skin of any worker in that the radiochemical can easily perch on them. * Before leaving the laboratory, workers should check themselves from radiation with beta-gamma survey meters * Nobody should work with radioactive materials if he has a broken skin-unless he wears gloves. 7. CHEMICAL HAZARDS For the purposes of this work, all chemicals used in routine laboratory, hemical manufacturing process and general research work are considered as hazardous, hence it is very important we understand this and follow strictly those safety rules guiding their usage. 8. CLASSES OF HAZARDOUS CHEMICALS * Class 1 – Explosives * Class 2 – Compresses gases and poisonous gases * Class 3 – Flammable liquids * Class 4 – Flammable solids 9. MANAGEMENT OF HAZARDOUS CHEMICALS As with radioactive materials, hazardous chemicals must be properly handle so as to prevent any health risk associated with their usage either directly or indirectly.
Because of this similar safety precautions must be observed as is the case with radiochemical materials In addition the following general safety rules must be observed when handling chemicals. 10. LABORATORY SAFETY General Safety Guidelines for Chemical Lab * Material Safety Data Sheets: Know the hazard potential of each chemical you are using. Familiarize yourself with the Material Safety Data Sheets (MSDS) for the materials you are using. * Personal Protection and First Aid * Wear eye protection (safety glasses or goggles) whenever you are working with material that can injure your eyes, especially acids, bases, and oxidizers. If you wear contact lenses, familiarize yourself with the special precautions. * Know the location of the emergency eye-wash stations, showers and first aid kits. Familiarize yourself with the operation of the eye wash station and shower. First aid kit is located in the chemistry lab. * Wear hand protection when handling corrosive or hazardous materials. The use of nitrile rubber is recommended when handling concentrated corrosive materials or organic solvents. Disposable PVC examining gloves offer minimal protection and are permeable to many organic substances. Check rubber gloves for holes and cracks before using. Do not touch surfaces with contaminated gloves. (Door knobs, equipment bench tops, drawers, etc. ) Rinse gloves well after use. * Open-toed shoes or sandals are not permitted in the chemistry labs. * Use of lab coats is recommended to protect your clothing. Protective aprons should be worn when handling highly corrosive materials. 11. CHEMICAL EMERGENCIES In a chemical emergency do not hesitate to follow these procedures because a spill or contact seems too trivial. It is better to overreact. * For skin contact, flood the affected area with water immediately and continues flooding for at least 15 minutes.
If a substantial portion of the body is involved, use a safety shower. If the chemical is toxic, or it its toxic properties are unknown. * For eye contact, flood eyes with water and continue flooding for at least 15 minutes. Remove contact lenses if possible, or move to corner of the eye. * For inhalation or ingestion, follow direction on the product label. In case of spillage of any chemical: * If the volume of spill is greater than 500 ml (1 pint), or any amount of extremely toxic substance is spilled, evacuate and seal the area. * If the volume of spill is less that 500 m. 1 pint) and the substance is not extremely toxic, check the container or MSDS for special instructions. If no instructions are immediately available, encircle and cover the spill with absorbent material until the liquid is adsorbed. Do not flush with water. Neutralize strong acids with sodium bicarbonate, sodium carbonate, or calcium hydroxide after absorbing. (Note: DO NOT absorb hydrofluoric acid- neutralize immediately). * Solid spills are not usually emergencies. If the spilled material is toxic, use damped cloths or paper towels to transfer the material to plastic bags.