Grade 7: Matter Unit 1 Basic concepts of Science

1.1 The Nature of Science and its Branches

We see various natural phenomena in our daily life. Natural phenomena are things that happen in
nature. Lightning, rainbow, melting of ice, growth of a baby into an adult and the fall of ball to the
ground are a few examples of natural phenomena. We want to know why and how all these things
happen. We search for answers. The study of science gives us the answers. 1.1.1 What is science?
Unit 1 Grade 7: Basic concepts of science The word science is derived from the Latin word “scientia”
which means Knowledge. Science is defined as a body of knowledge and processes by which
knowledge is produced. It is a study of the physical and natural world. Science provides an ordered
way of learning about the nature of things, based on observation and evidence. Through science, we
explore our environment, gather knowledge and develop ideas that help us interpret and explain
what we see. When some people think of science, they think of formulas and facts to memorize.
Commonly, they are used to see the "body of knowledge" component of science. These are
sometimes presented with scientific concepts in statement form – Earth is round, electrons are
negatively charged, our genetic code is contained in our DNA, and the universe is 13.7 billion years
old. Usually, with a little background about the process that led to that knowledge, we trust it. The
scientific process is a way of building knowledge and making predictions about the world in such a
way that they are testable. For example, a question of whether Earth is flat or round could be put to
the test, it could be studied through multiple lines of research, and the evidence evaluated to
determine whether it supported a round or flat planet. These are processes. Among the processes of
science, observation, measurement, prediction, estimation, and communication are the major ones.
Science studies the natural world. This studies includes the components of the physical universe
around us like atoms, plants, ecosystems, people, societies, and galaxies, as well as the natural
forces at work on them. It investigates all sorts of questions: for example:- • What causes gravity? •
Why do leaves fall from trees after turning yellow? • How do our brains store memories? • How do
water molecules interact with each other? • How are diseases caused and how to prevent and cure
them? Then scientists make observations, conduct experiments, and give answers to these
questions. . In addition to a body of knowledge that includes formulas and facts, science is a practice
by which we pursue answers to questions that can be approached scientifically. This practice is
referred to as scientific research. Conventional Science and Indigenous Science As it has been said,
the primary goal of science is to understand the natural and human-designed worlds. It is used by
humans for obtaining knowledge about nature. Science is a dynamic and creative activity with a long
and interesting history. Many societies have contributed to the development of scientific knowledge
and Therefore it is possible to divide science into two Conventional science and Indigenous science.
The term "Indigenous” can be defined as decent people who inhabited the geographical region to
which they belong. Therefore Indigenous science is local, community-based system of knowledge
that is unique to a given culture or society. It is a general term that refers broadly to the collective
knowledge of Indigenous people about relationships between people, habitat, and nature. It
includes practices and technologies used both in the past and present by indigenous peoples for
their survival in a variety of environments. Some knowledge may be common to all members of a
community, and as such may be easier to share with outsiders. Certain specialized pieces of
knowledge are held only by some members of the community. Indigenous scientists specialize in
trades such as herbal medicines, village traditional health and spiritual counseling, and measuring
weather cycles. Terms such as “modern science,” “Western science,” and “conventional science,”
have been in use only since the beginning of the twentieth century. Modern science also called
conventional science thought in school classrooms. Conventional science relies on certain laws that
have been established through the application of scientific methods. The process of the scientific
methods is linked with an observation followed by a prediction or hypothesis which is then tested.
Depending on the test results the hypothesis can become a scientific theory about the world.
Scientists distinguish between conventional and indigenous science by claiming that conventional
science is universal whereas indigenous science focuses only to particular people and their
understanding of the world. The other difference between them is that conventional science focuses
the components parts whereas indigenous science present information about the world in a holistic
way. Indigenous science knowledge is transferred by storytelling and has no documentation. Unlike
this in conventional science knowledge transfer is by written document. Likewise in indigenous
science learning is by doing and experiencing while it is by formal education in conventional
learning. Science is mainly divided into four main branches. They are Natural science, Social Science,
Formal Science and Applied science. Each of these branches has sub-branches according to the
nature of the subject. Natural Science is a branch of science concerned with the description, and
understanding of natural phenomena. It includes three main subject areas; physics, biology and
chemistry. • Physics - study of matter, motion, force and energy. It can describe how the system is
placed on the space, the motion of the system, and other physical properties. Mainly it has two
branches, but also divided into subdivisions. These are classical physics (Mechanics, Sound, Optics,
Electromagnetism, Heat and thermodynamics) and Modern physics (Atomic, Nuclear, Quantum
physics, and space exploration). Table 1.1. Branches of physics Branches of physics Branches Main
Focus (Studies about) Mechanics Force acting on object whether at rest or in motion
Thermodynamics The relationship between heat and other forms of energy Electromagnetism
Electricity and magnetism and their mutual relationship Quantum physics discrete nature of
phenomenon at atomic and sub atomic level. Atomic physics the structure and property of atom.
Nuclear physics the structure, property and reaction of the nuclei of atom • Biology - All living things
are studied under biology. In Biology, there are three main branches i.e. Zoology, Botany and Micro
biology. • Chemistry - Chemistry is the study of matter, analyzing its structure, properties and
change in chemical reactions. There are five branches; these are Organic chemistry, Inorganic
chemistry, Analytic chemistry, Biochemistry and Physical chemistry. Table 1.2. Branches of chemistry
Branches of chemistry Branches Main focus 1. Organic Study of carbon containing compounds. 2.
Inorganic study of compound that do not contain carbon 3. Analytical Analyzing the composition of
materials. 4. Physical Concerned with the behavior of materials. 5. Biochemistry Study of the
chemistry of living organisms. Formal science is a branch of science studying disciplines concerned
with formal systems, such as logic, mathematics, statistics, and theoretical computer science. Social
Science is the study of human behavior in its social and cultural aspects. Some of the branches of
social science are law, History, Economics, Sociology, Education, and Political science.
iv. What is applied science? Applied science is study about theories of a subject applying for the
humans’ applications. All of the industrial application comes with applied sciences studies. Beside
this, all science subjects have an applied science area, for example, applied physics, applied
mathematics, Applied Biology, etc. It includes a broad range of disciplines Such as computer, civil,
chemical and electrical engineering and industrial engineering. 1.1.3 Relationship of Different
Branches of Science Different branches of science have relationship with one another. For instance
the concept of matter is made up of different atoms is a subject of physics. The structure of atom is
also included in physics. But the formation of molecule and its cause is subject of c hemistry.
Therefore physics and chemistry are associated with each other on these subjects of study. There is
great relationship between chemistry and Biology as well. In biology functioning of different organ
and their structure described. Beside this the chemical nature of different living bodies and chemical
reactions taking place in them are studied in chemistry, which is called biochemistry. Mathematical
assistance is applied for physics and chemistry. Many laws of chemistry and physics are derived from
mathematics. Some of branches of science studied by more than branches of science are mentioned
below. Biophysics – biology studied with the help of principles of physics. Unit 1 Grade 7: Basic
concepts of science Biochemistry- Biology studied with the help of chemistry. Geophysics - Different
aspect and features of land are analyzed with the help of physics. 1.1.4 The role of Science and
Technology in our life The words science and technology can and often are used interchangeably.
But the goal of science is the pursuit of knowledge while the goal of technology is to create products
that solve problems and improve human life. Simply put, technology is the practical application of
science. Science contributes to ensuring a longer and healthier life, monitors our health, provides
medicine to cure our diseases, and alleviates aches and pains. It helps us to provide water for our
basic needs. It also benefits in providing our food, energy and making life more fun, including sports,
music, entertainment and the latest communication technology. Science has built up our
understanding of electricity and the relationship between electricity and magnetism. The generation
and supply of electricity enable the carrying of our voices over telephone lines, bringing
entertainment to our televisions, and keeping the lights on. Generally, it is used to run industrial and
Unit 1 Grade 7: Basic concepts of science home appliances. From the eradication of smallpox to the
prevention of nutritional deficiencies, to successful treatments for once deadly infections, the use of
life-saving drug and diagnostic instruments has been increased greatly. In fact, without science,
many people alive today would have instead died of diseases that are now easily treated. In the
agriculture sector, the production of high-yielding variety, the invention of pesticides and fertilizers
and farm machines is the result of science and technology. This has great role in realizing food
security. In Industrial sector the use of automatic electrical and mechanical machines, in
communication introduction of supersonic planes, electrical trains are the result of advancement in
the field of science and technology. Various discoveries and inventions in the present century have
brought a revolution in communication sector. Wireless, telephone, radio, television, computer,
satellites have interlinked the whole world. Science and technology has made man travel to space.
Advantages and disadvantages of science Advantages of science 1. Industrialization Science has
brought a great revolution in terms of economic progress due to industrialization. Industrialization
has changed us from toes to hair of head. We have variety of things available at shopping malls and
industrial outlets. Unit 1 Grade 7: Basic concepts of science 2. Surplus food Stories of famine and
droughts are now the part of ancient history. Science has accelerated production of cereals, fruits,
meat and vegetables. Modern man enjoys a variety of edibles. 3. Fast travelling and communication
Aero-planes, Air conditioned buses, ships and bullet trains have shortened the geographical
distances. Modern man travels through oceans, air, mountains landscapes at a greater speed. Now
the world is at the distance of click. Internet, Television, Radio and fax have enabled us to enjoy
communication with global community just like our family members. 4. Innovation Science has
brought innovation in every field of life. Distance learning, connected classroom technology and
online courses have changed the concept of education. Now education has become a global
concern. Modern tools are being used in investigation of diseases once were a challenge in health
department. Technology is being shifted from garage to pocket due to innovative research done in
scientific field. 5. Problem solving technique Scientific progress has changed our thought process.
Modern man applies scientific approach to daily life problems. It has given us computational control
over the world. Disadvantages of science 1. Unemployment Solving a problem generates a new
problem as a by-product. Industrialization has replaced human beings with machines. It has Unit 1
Grade 7: Basic concepts of science accelerated economic progress many fold but at the same time
unemployment is increasing due to machines. 2. Pollution Industrialization has increased pollution
level. Greenhouse effect has caused global warming which is a threat-call to our future. The world is
consuming billions of dollars every year to neutralize or reverse this issue but the problem is still
going out of control. Pollution is the by-product of scientific progress and industrialization. 3. Human
total destruction Scientific progress has made the world more divided and less stable as compared
to the past. Modern man has invented atom bombs, hydrogen bombs, Nuclear Bombs and missile
technology for the destruction of fellow beings. These weapons are increasing feelings of insecurity
across the globe. 4. Uncertain future The world is becoming prone to 3rd world war as more and
more flash points are emerging on the map of the globe. Perhaps it will be the last world war on this
planet. 1.1.5 Famous Scientists of the World and Ethiopia From the very first moment humans
appeared on the planet, we have attempted to understand and explain the world around us. The
most insatiably curious among us often have become scientists. They have shaped humankind’s
knowledge and laid the foundation for virtually every scientific discipline. Here are some of
international and Ethiopian scientists with their contributions. International scientists with their
contribution. 1. Abu Ali Ibn Sina Abu Ali Ibn Sina better recognized to the West as Avicenna. He
alone wrote 246 books. His creative influences involved such developments such as
acknowledgment of the communicable nature of phthisis and tuberculosis; spreading of diseases by
water and soil and the collaboration between psyc Fig. 1.2 Abu Ali ibn Sina Sina was also the first to
describe meningitis and prepared ironic contributions to anatomy, gynecology and child health. 2.
Marie Curie Physicist and chemist Marie Curie was famous for her work on radioactivity. She was the
first scientist to isolate polonium and radium; she established the nature of radiation and beta rays.
Her work led to the development of the X-ray and research into atomic particles. 3. Stephen William
Hawking Physicist Stephen William Hawking developed a theory of exploding black holes that drew
upon both relativity theory and quantum mechanics. He also worked with space-time singularities
Fig. 1.3 Marie Curie Fig. 1.4 Stephen William Hawking Unit 1 Grade 7: Basic concepts of science
Ethiopian scientists with their contributions. 1. Zeki Abdullahi sherif He is a professor at Georgetown
University, Washington, D.C. teaching and researching in the area of molecular medicine and cancer
in the department of biochemistry and molecular biology at the school of medicine. H Fig. 1.5 Zeki
Abdullahi sherif gene named ZS (acronym for zeki sherif) that may predispose certain individuals and
groups to cancer. He has been recognized for his scientific work with national and international
awards including the Hall of fame award and international union of cancer researchers. 2. Gebissa
Ejeta During the early 1980s, Ejeta developed Africa's first commercial hybrid variety of sorghum
tolerant to drought. Later, with a Purdue University colleague in Indiana, he discovered the chemical
basis of the relationship between the deadly parasitic weed striga and sorghum, and was able to
produce sorghum varieties resistant to both drought and striga. Ejeta was awarded the 2009 World
Food Prize, considered the Nobel Prize for food and agriculture, for research that “enhanced food
security for hundreds of millions of people in sub-Saharan Africa.” Ejeta has advised numerous
international and U.S. government agencies, including the United States Agency for International
Development. In 2011 President Fig. 1.6 Gebissa Ejeta Unit 1 Grade 7: Basic concepts of science
Obama appointed him to the Board for International Food and Agricultural Development. 3. Sossina
M.hailu She is a chemist, known for developing the first solid acid fuel cells. Most recently, She has
received recognition for developing new ways of using solar energy to make fuels like hydrogen and
methane. She is a professor of Materials Science and Engineering at Northwestern University,
Illinois, USA. She received the National Science Foundation National Young Investigator Award, and
in 2001 She earned the J.B. Wagner Award of theFig. 1.7 Sossina M.hailu High Temperature
Materials Division High-Temperature chemical Society, the 2000 Coble Award from the American
Ceramic Society, and the 1997 TMS Robert Lansing Hardy Award. Ethics refer to moral principles
that govern a person’s behavior. Ethics in science are the principles that scientists must follow Unit 1
Grade 7: Basic concepts of science while conducting their research. It creates a strong foundation for
trustworthy and undeniable findings that can be accepted all over the world by the scientific
community. Ethics in science is important in promoting the aim of science such as building
knowledge, truth, and avoidance of error. For example, prohibitions against fabricating, falsifying, or
misrepresenting data used in science practices. In scientific investigation there are standards of
conduct scientists should follow. These ethical discipline are the following. 1. Scientific data should
be reported honestly. It is wrong and misleading to make up or change research results. 2. Scientific
results should be carefully recorded and analyzed to avoid errors. Avoid biased results. 3. Scientists
must inform coworkers and members of the community about any risks of their research. They
should do the research only if they have the agreement of these groups. 4. Sufficient proof of results
through replication and collaboration with peers; 5. Scientists studying living animals must treat
them humanely. They should provide for their needs and take pains to avoid harming them. 6.
Scientific results should be communicated through publication. The public should be informed so it
can make better decisions, the argument states. 7. In the scientific investigation it is necessary to
acknowledge sources of information and data. Unit 1 Grade 7: Basic concepts of science 1.2.
Common laboratory Equipment, Uses, Safety Rules and Procedures in Science Laboratories Unit 1
Grade 7: Basic concepts of science Laboratory apparatus are the tools required to complete
laboratory work including beakers, test tubes, pipettes, graduated cylinders etc. Beakers are useful
as a reaction container, to hold liquid and solid samples. Graduated cylinders come in a variety of
sizes and are used primarily to measure accurate volumes of chemicals or solutions. Unit 1 Grade 7:
Basic concepts of science Pipets come in a variety of volumes and are used to accurately measure
and transfer volumes of chemicals or solutions. Pipets are typically used to measure smaller volumes
than graduated cylinders. Burets are available laboratory in a variety of volumes and are used to
accurately deliver volumes of solutions. Burets are similar to pipets, but the difference is that burets
have a valve at the bottom of the cylinder that can be used to add very small and precise volumes of
a solution. Many different types of flasks are used in science laboratory. Unit 1 Grade 7: Basic
concepts of science Erlenmeyer flasks are commonly used for storing and mixing liquids. They are
made in a number of volumes and are typically used to store or mix chemicals or to conduct
chemical reactions. Another type of flask is a volumetric flask, which is made to contain a very
precise amount of chemicals. Volumetric flasks are usually used to prepare standard solutions.
Balance is used to find the mass of an object. The most common types of scale balances are the
beam balance (figure 1.13) and the electronic balance (figure 1.14). Both types of balances measure
mass in grams. Unit 1 Grade 7: Basic concepts of science A Bunsen burner uses gas to produce a
flame. The flame of a Bunsen burner can reach temperatures up to 1500°C. Bunsen burners are used
to heat liquids and solid objects. Test tube holders are used for holding test tubes. Tongs are similar
in function to forceps but are useful for larger items. Test tube is glassware that made in many sizes;
it is used to hold chemicals, to carry out sample chemical reactions in it. Test tube rack Used to hold
test tubes while reactions happen in them or while they are not needed. Brushes Used to easily
clean test tubes, cylinders and other glassware. Unit 1 Grade 7: Basic concepts of science
Evaporating dish: Used to recover dissolved solids after evaporation. Petri dish: used to culture
different types of cells, including bacteria and other microorganisms. Thermometer: A thermometer
is an instrument that measures temperature. Improvisation is the process of producing or preparing
teaching and learning materials from readily available and locally cheap and used Unit 1 Grade 7:
Basic concepts of science Laboratory safety rules andprocedures Laboratory safety rules are
principles or regulations governing actions, procedures, intended to reduce risks in the laboratory.
Basic Safety Rules Basic safety rules for laboratory conduct should be observed whenever working in
a laboratory. Many of the most common safety rules are listed below. 1. No student may work in the
laboratory without the teacher’s supervision. 2. Carry out only the experiments assigned by the
teachers. 3. Eating, drinking, and chewing gum are not allowed in the laboratory. 4 Keep your work
area neat and clean. 5. Tie back loose hair. 6. Do not taste or smell chemicals. 7. Never add water to
concentrated acid solutions. Because the heat generated may cause splashing. 8. Be careful not to
touch your eyes or other body areas without thoroughly washing your hands first. 9. Report all
accidents or injuries (burn, cut, chemical splash, electrical shock etc…) 10. Before leaving the
laboratory, see that: a. Your desktop and work area is thoroughly clean. b. All equipment in drawer
is complete and well organized. c. Unplug electrical sockets, and switch off the light. d. You wash
your hands before leaving the laboratory. Unit 1 Grade 7: Basic concepts of science Personal
protective Equipment Personal protective equipment (PPE) includes safety glasses, goggles, face
shields, gloves, laboratory coats, ear plugs, and respirators. Personal protective equipment is
carefully selected to ensure that it is compatible with the chemicals and the process used. Chemical
goggles Shield the eyes against liquid or chemical splash, irritating mists, vapors, and fumes. Safety
glasses or chemical goggles must be put on before entering laboratory. Laboratory Coats  Shall be
worn before handling chemicals, and biological specimen.  Shall cover the wearer to the knees.
Face Protection Eye glass Laboratory coat  Face shields worn over safety glasses may be required
for certain processes. Face mask Unit 1 Grade 7: Basic concepts of science Hand Protection  Gloves,
especially, should be chosen carefully. They must be resistant to the chemicals being used. Hand
protection (gloves) Hazard Symbols A hazard is something that could cause: harm to someone,
damage to something or adverse health effects. Hazard symbols are used on containers. They are
used to:  Indicate the dangers associated with the substance inside a container.  Give information
about how to work safely with the substance in the laboratory.  Hazard symbols are designed to
provide a warning, even if a person cannot understand the writing that goes with them. Unit 1
Grade 7: Basic concepts of science Hazard Signs (Symbols) Unit 1 Grade 7: Basic concepts of science
Unit 1 Grade 7: Basic concepts of science Unit Summary • Science is defined as a body of knowledge
and processes by which knowledge is produced. It is a study of the physical and natural world. •
Among the processes of science, observation, measurement, prediction, estimation, and
communication are the major ones. • Science investigates all sorts of questions. Then scientists
make observations, conduct experiments, and give answers to these questions. • Indigenous science
is local, community-based system of knowledge that is unique to a given culture or society. It is the
collective knowledge of Indigenous people about relationships between people, habitat, and nature.
• Conventional science relies on certain laws that have been established through the application of
scientific methods. • Conventional science is universal whereas indigenous science focuses only to
particular people and their understanding of the world. • Conventional science focuses on the
components parts whereas indigenous science presents information about the world in a holistic
way. • Science has four main branches, i.e. Natural science, and Social Science, Formal Science, and
Applied science. Unit 1 Grade 7: Basic concepts of science • Different branches of science have
relationship with one another, some of them are biophysics, biochemistry and geophysics. • Science
has greatly changed human life in the generation of supply of electricity, the discovery of drugs and
treatments, in production of high-yielding crops, the creation of automated and mechanical
machines, and improving transport and communication. • Science has advantages but also has some
disadvantages, the advantages are Industrialization, surplus food production, fast traveling and
communication, innovation and problem- solving technics are the main. The disadvantages are
unemployment, pollution, human total destruction, and an uncertain future. • Honesty of data,
careful recorded and analyzed data, working in collaboration, communication of scientific results,
and acknowledging the sources are the main in scientific ethics. • Laboratory equipment refers to
various kit used in a laboratory to perform different tasks. • Laboratory equipment enable us to
carry out experiments successfully and make accurate measurements or observations. • All common
laboratory apparatus should be drawn in outline only and in their correct proportions. Unit 1 Grade
7: Basic concepts of science Unit 1 Grade 7: Basic concepts of science Review Exercise Part I. Write
true for the correct statements and false for the wrong statements. 1. Science makes an
observation, conduct experiment, and gives answers to questions raised. 2. Formula and scientific
facts are processes of science. 3. You should always wash your hands before leaving laboratory. 4.
Eating, drinking, and chewing gum are allowed in the laboratory. 5. In scientific investigation
acknowledging the source of information is not necessary. 6. It is good practice to carry the
microscope with one hand. 7. Students must know the location of all safety equipment. 8. Science
can be contributed by scientists and indigenous people. 9. Conventional science is universal while
indigenous science focuses on particular people. 10. Laboratory coats must be taken off when
exiting the laboratory and entering anon-laboratory area. 11. Scientific data should be reported
honestly. 12. Technology is the body of knowledge and process. Part II. Matching A B 1. Physics a.
Transport technology product 2. Botany b. Study of carbon-containing compounds. 3.
Thermodynamics c. Formal science 4. Organic chemistry d. Study of motion, matter and energy Unit
1 Grade 7: Basic concepts of science Unit 1 Grade 7: Basic concepts of science Unit 1 Grade 7: Basic
concepts of science 10. You should always hold containers that have chemicals: A. with a pair of
rubber gloves. B. with a clean pair of tongs. C. away from your body. D. close to your chest and with
a strong grip. 11. When diluting an acid with water, always remember to: A. Pour water into acid C.
Pour acid into water B. Add both at the same time D. All 12. Which one of the following can be the
cause of Human total destruction? A. Hunger C. AIDS B. Nuclear Bomb D. Unemployment Part IV. Fill
the following blank spaces with appropriate words. 1. Through science we explore our . 2.
investigates all sorts of question. 3. The practice of science is referred to us . 4. Conventional science
uses method. 5. Science present information about the world in a holistic way. 6. refers to moral
principles that govern a person’s behavior. Part V. Give short answers for each of the following
Questions. 1. What is science mean? Define science. 2. What are the examples of body of
knowledge?
Unit 1
Basic concepts of Science
1.1.1 What is science?
1.1 The Nature of Science and its Branches
The word science is derived from the Latin word “scientia” which
means Knowledge. Science is defined as a body of knowledge and
processes by which knowledge is produced. It is a study of the
physical and natural world. Science provides an ordered way of
learning about the nature of things, based on observation and
evidence. Through science, we explore our environment, gather
knowledge and develop ideas that help us interpret and explain what
we see.
When some people think of science, they think of formulas and facts
to memorize. Commonly, they are used to see the "body of
knowledge" component of science. These are sometimes presented
with scientific concepts in statement form – Earth is round, electrons
are negatively charged, our genetic code is contained in our DNA,
and the universe is 13.7 billion years old. Usually, with a little
background about the process that led to that knowledge, we trust it.
The scientific process is a way of building knowledge and making
predictions about the world in such a way that they are testable. For
example, a question of whether Earth is flat or round could be put
to the test, it could be studied through multiple lines of research,
and the evidence evaluated to determine whether it supported a
round or flat planet. These are processes. Among the processes of
science, observation, measurement, prediction, estimation, and
communication are the major ones.
Science studies the natural world. This studies includes the
components of the physical universe around us like atoms, plants,
ecosystems, people, societies, and galaxies, as well as the natural
forces at work on them. It investigates all sorts of questions: for
example:-
 What causes gravity?
 Why do leaves fall from trees after turning yellow?
 How do our brains store memories?
 How do water molecules interact with each other?
 How are diseases caused and how to prevent and cure
them?
Then scientists make observations, conduct experiments, and give
answers to these questions. . In addition to a body of knowledge
that includes formulas and facts, science is a practice by which we
pursue answers to questions that can be approached scientifically.
This practice is referred to as scientific research.
Conventional Science and Indigenous Science
As it has been said, the primary goal of science is to understand the
natural and human-designed worlds. It is used by humans for
obtaining knowledge about nature. Science is a dynamic and
creative activity with a long and interesting history. Many societies
have contributed to the development of scientific knowledge and
understanding.
Therefore it is possible to divide science into two Conventional
science and Indigenous science. The term "Indigenous” can be
defined as decent people who inhabited the geographical region to
which they belong. Therefore Indigenous science is local,
community-based system of knowledge that is unique to a given
culture or society. It is a general term that refers broadly to the
collective knowledge of Indigenous people about relationships
between people, habitat, and nature.
It includes practices and technologies used both in the past and
present by indigenous peoples for their survival in a variety of
environments. Some knowledge may be common to all members of a
community, and as such may be easier to share with outsiders.
Certain specialized pieces of knowledge are held only by some
members of the community. Indigenous scientists specialize in trades
such as herbal medicines, village traditional health and spiritual
counseling, and measuring weather cycles.
Terms such as “modern science,” “Western science,” and
“conventional science,” have been in use only since the beginning of
the twentieth century. Modern science also called conventional
science thought in school classrooms.
Conventional science relies on certain laws that have been
established through the application of scientific methods. The
process of the scientific methods is linked with an observation
followed by a prediction or hypothesis which is then tested.
Depending on the test results the hypothesis can become a scientific
theory about the world.
Scientists distinguish between conventional and indigenous science
by claiming that conventional science is universal whereas
indigenous science focuses only to particular people and their
understanding of the world.
The other difference between them is that conventional science
focuses the components parts whereas indigenous science present
information about the world in a holistic way.
Indigenous science knowledge is transferred by storytelling and has
no documentation. Unlike this in conventional science knowledge
transfer is by written document. Likewise in indigenous science
learning is by doing and experiencing while it is by formal education
in conventional learning.
Science is mainly divided into four main branches. They are Natural
science, Social Science, Formal Science and Applied science. Each
of these branches has sub-branches according to the nature of the
subject.
Natural Science is a branch of science concerned with the
description, and understanding of natural phenomena. It includes
three main subject areas; physics, biology and chemistry.
1.1.2 Branches of Science
i. What is Natural science?
 Physics - study of matter, motion, force and energy. It can
describe how the system is placed on the space, the motion
of the system, and other physical properties. Mainly it has
two branches, but also divided into subdivisions. These are
classical physics (Mechanics, Sound, Optics, Electromagnetism,
Heat and thermodynamics) and Modern physics (Atomic,
Nuclear, Quantum physics, and space exploration).
Table 1.1. Branches of physics
Branches of physics
Branches Main Focus (Studies about)
Mechanics Force acting on object whether at rest or in motion
Thermodynamics The relationship between heat and other forms of
energy
Electromagnetism Electricity and magnetism and their mutual
relationship
Quantum physics discrete nature of phenomenon at atomic and sub
atomic level.
Atomic physics the structure and property of atom.
Nuclear physics the structure, property and reaction of the nuclei of
atom
 Biology - All living things are studied under biology. In
Biology, there are three main branches i.e. Zoology, Botany
and Micro biology.
Fig 1.1. The main branches of biology.
 Chemistry - Chemistry is the study of matter, analyzing its
structure, properties and change in chemical reactions.
There are five branches; these are Organic chemistry,
Inorganic chemistry, Analytic chemistry, Biochemistry and
Physical chemistry.
Table 1.2. Branches of chemistry
Branches of chemistry
Branches Main focus
1. Organic Study of carbon containing
compounds.
2. Inorganic study of compound that do not
contain carbon
3. Analytical Analyzing the composition of
materials.
4. Physical Concerned with the behavior of
materials.
5. Biochemistry Study of the chemistry of living
organisms.
Formal science is a branch of science studying disciplines
concerned with formal systems, such as logic, mathematics,
statistics, and theoretical computer science.
Social Science is the study of human behavior in its social and
cultural aspects. Some of the branches of social science are law,
History, Economics, Sociology, Education, and Political science.
ii. What is Formal Science?
iii. What is social Science?
Applied science is study about theories of a subject applying for the
humans’ applications. All of the industrial application comes with
applied sciences studies. Beside this, all science subjects have an
applied science area, for example, applied physics, applied
mathematics, Applied Biology, etc. It includes a broad range of
disciplines Such as computer, civil, chemical and electrical
engineering and industrial engineering.
Different branches of science have relationship with one another.
For instance the concept of matter is made up of different atoms is a
subject of physics. The structure of atom is also included in
physics. But the formation of molecule and its cause is subject of c
hemistry. Therefore physics and chemistry are associated with each
other on these subjects of study.
There is great relationship between chemistry and Biology as well.
In biology functioning of different organ and their structure
described. Beside this the chemical nature of different living bodies
and chemical reactions taking place in them are studied in
chemistry, which is called biochemistry.
Mathematical assistance is applied for physics and chemistry. Many
laws of chemistry and physics are derived from mathematics.
Some of branches of science studied by more than branches of
science are mentioned below.
Biophysics – biology studied with the help of principles of physics.
iv. What is applied science?
1.1.3 Relationship of Different Branches of Science
Biochemistry- Biology studied with the help of chemistry.
Geophysics - Different aspect and features of land are analyzed
with the help of physics.
The words science and technology can and often are used
interchangeably. But the goal of science is the pursuit of knowledge
while the goal of technology is to create products that solve problems
and improve human life. Simply put, technology is the practical
application of science.
Science contributes to ensuring a longer and healthier life, monitors
our health, provides medicine to cure our diseases, and alleviates
aches and pains. It helps us to provide water for our basic needs. It
also benefits in providing our food, energy and making life more
fun, including sports, music, entertainment and the latest
communication technology.
Science has built up our understanding of electricity and the
relationship between electricity and magnetism. The generation and
supply of electricity enable the carrying of our voices over
telephone lines, bringing entertainment to our televisions, and
keeping the lights on. Generally, it is used to run industrial and
1.1.4 The role of Science and Technology in our lif
From the eradication of smallpox to the prevention of nutritional
deficiencies, to successful treatments for once deadly infections, the
use of life-saving drug and diagnostic instruments has been
increased greatly. In fact, without science, many people alive today
would have instead died of diseases that are now easily treated.
In the agriculture sector, the production of high-yielding variety,
the invention of pesticides and fertilizers and farm machines is the
result of science and technology. This has great role in realizing
food security.
In Industrial sector the use of automatic electrical and mechanical
machines, in communication introduction of supersonic planes,
electrical trains are the result of advancement in the field of science
and technology.
Various discoveries and inventions in the present century have
brought a revolution in communication sector. Wireless, telephone,
radio, television, computer, satellites have interlinked the whole
world. Science and technology has made man travel to space.
Advantages and disadvantages of science
Advantages of science
1. Industrialization
Science has brought a great revolution in terms of economic progress
due to industrialization. Industrialization has changed us from toes to
hair of head. We have variety of things available at shopping malls
and industrial outlets.
2. Surplus food
Stories of famine and droughts are now the part of ancient history.
Science has accelerated production of cereals, fruits, meat and
vegetables. Modern man enjoys a variety of edibles.
3. Fast travelling and communication
Aero-planes, Air conditioned buses, ships and bullet trains have
shortened the geographical distances. Modern man travels through
oceans, air, mountains landscapes at a greater speed. Now the world
is at the distance of click. Internet, Television, Radio and fax have
enabled us to enjoy communication with global community just like
our family members.
4. Innovation
Science has brought innovation in every field of life. Distance
learning, connected classroom technology and online courses have
changed the concept of education. Now education has become a
global concern. Modern tools are being used in investigation of
diseases once were a challenge in health department. Technology is
being shifted from garage to pocket due to innovative research done
in scientific field.
5. Problem solving technique
Scientific progress has changed our thought process. Modern man
applies scientific approach to daily life problems. It has given us
computational control over the world.
Disadvantages of science
1. Unemployment
Solving a problem generates a new problem as a by-product.
Industrialization has replaced human beings with machines. It has
accelerated economic progress many fold but at the same time
unemployment is increasing due to machines.
2. Pollution
Industrialization has increased pollution level. Greenhouse effect has
caused global warming which is a threat-call to our future. The world
is consuming billions of dollars every year to neutralize or reverse
this issue but the problem is still going out of control. Pollution is the
by-product of scientific progress and industrialization.
3. Human total destruction
Scientific progress has made the world more divided and less stable
as compared to the past. Modern man has invented atom bombs,
hydrogen bombs, Nuclear Bombs and missile technology for the
destruction of fellow beings. These weapons are increasing feelings
of insecurity across the globe.
4. Uncertain future
The world is becoming prone to 3rd world war as more and more
flash points are emerging on the map of the globe. Perhaps it will be
the last world war on this planet.
From the very first moment humans appeared on the planet, we have
attempted to understand and explain the world around us. The most
insatiably curious among us often have become scientists. They have
shaped humankind’s knowledge and laid the foundation for virtually
every scientific discipline.
1.1.5 Famous Scientists of the World and Ethiopia
International scientists with their contribution.
1. Abu Ali Ibn Sina
Abu Ali Ibn Sina better recognized to the West
as Avicenna. He alone wrote 246 books. His
creative influences involved such
developments such as acknowledgment of the
communicable nature of phthisis and
tuberculosis; spreading of diseases by water
and soil and the collaboration between psychology and health. Ibn
Sina was also the first to describe meningitis and prepared ironic
contributions to anatomy, gynecology and child health.
2. Marie Curie
Physicist and chemist Marie Curie was
famous for her work on radioactivity. She
was the first scientist to isolate polonium
and radium; she established the nature of
radiation and beta rays. Her work led to the
development of the X-ray and research into
atomic particles.
3. Stephen William Hawking
Physicist Stephen William Hawking
developed a theory of exploding black holes
that drew upon both relativity theory and
quantum mechanics. He also worked with
space-time singularities
Ethiopian scientists with their contributions.
1. Zeki Abdullahi sherif
He is a professor at Georgetown University,
Washington, D.C. teaching and researching in
the area of molecular medicine and cancer in
the department of biochemistry and molecular
biology at the school of medicine. He was able to isolate a novel
gene named ZS (acronym for zeki sherif) that may predispose certain
individuals and groups to cancer. He has been recognized for his
scientific work with national and international awards including the
Hall of fame award and international union of cancer researchers.
2. Gebissa Ejeta
During the early 1980s, Ejeta developed Africa's first commercial
hybrid variety of sorghum tolerant to drought. Later, with a Purdue
University colleague in Indiana, he discovered the chemical basis of
the relationship between the deadly parasitic weed striga and
sorghum, and was able to produce sorghum varieties resistant to both
drought and striga.
Ejeta was awarded the 2009 World Food Prize, considered the Nobel
Prize for food and agriculture, for research that
“enhanced food security for hundreds of millions of
people in sub-Saharan Africa.” Ejeta has advised
numerous international and U.S. government
agencies, including the United States Agency for
International Development. In 2011 President
Obama appointed him to the Board for International Food and
Agricultural Development.
3. Sossina M.hailu
She is a chemist, known for developing the first solid acid fuel cells.
Most recently, She has received recognition for developing new ways
of using solar energy to make fuels like
hydrogen and methane. She is a professor of
Materials Science and Engineering at
Northwestern University, Illinois, USA. She
received the National Science Foundation
National Young Investigator Award, and in
2001 She earned the J.B. Wagner Award of the
High Temperature Materials Division High-Temperature chemical
Society, the 2000 Coble Award from the American Ceramic Society,
and the 1997 TMS Robert Lansing Hardy Award.
Ethics refer to moral principles that govern a person’s behavior.
Ethics in science are the principles that scientists must follow
while conducting their research. It creates a strong foundation for
trustworthy and undeniable findings that can be accepted all over the
world by the scientific community. Ethics in science is important in
promoting the aim of science such as building knowledge, truth, and
avoidance of error. For example,
prohibitions against fabricating, falsifying, or misrepresenting data
used in science practices.
In scientific investigation there are standards of conduct scientists
should follow. These ethical discipline are the following.
1. Scientific data should be reported honestly. It is wrong and
misleading to make up or change research results.
2. Scientific results should be carefully recorded and analyzed to
avoid errors. Avoid biased results.
3. Scientists must inform coworkers and members of the
community about any risks of their research. They should do
the research only if they have the agreement of these groups.
4. Sufficient proof of results through replication and
collaboration with peers;
5. Scientists studying living animals must treat them humanely.
They should provide for their needs and take pains to avoid
harming them.
6. Scientific results should be communicated through
publication. The public should be informed so it can make
better decisions, the argument states.
7. In the scientific investigation it is necessary to acknowledge
sources of information and data.
1.2. Common laboratory Equipment, Uses, Safety Rules and
Procedures in Science Laboratories
Laboratory apparatus are the tools required to complete laboratory
work including beakers, test tubes, pipettes, graduated cylinders etc.
Beakers are useful as a reaction container, to hold liquid and solid
samples.
Graduated cylinders come in a variety of sizes and are used primarily
to measure accurate volumes of chemicals or solutions.
Pipets come in a variety of volumes and are used to accurately
measure and transfer volumes of chemicals or solutions. Pipets are
typically used to measure smaller volumes than graduated cylinders.
Burets are available laboratory
in a variety of volumes and are
used to accurately deliver
volumes of solutions.
Burets are similar to pipets, but
the difference is that burets have
a valve at the bottom of the cylinder that can be used to add very
small and precise volumes of a solution.
Many different types of flasks are used in science laboratory.
Erlenmeyer flasks are commonly used for storing and mixing liquids.
They are made in a number of volumes and are typically used to
store or mix chemicals or to conduct chemical reactions.
Another type of flask is a volumetric flask, which is made to contain
a very precise amount of chemicals. Volumetric flasks are usually
used to prepare standard solutions.
Balance is used to find the mass of an object. The most common
types of scale balances are the beam balance (figure 1.13) and the
electronic balance (figure 1.14). Both types of balances measure
mass in grams.
Equipment for Measuring Mass
A Bunsen burner uses gas to produce a flame. The flame of a
Bunsen burner can reach temperatures up to
1500°C. Bunsen burners are used to heat
liquids and solid objects.
Test tube holders are used for holding test tubes.
Tongs are similar in function to forceps but are useful for larger
items.
Test tube is glassware that made in many sizes; it is used to hold
chemicals, to carry out sample chemical reactions in it.
Test tube rack Used to hold test tubes while reactions happen in
them or while they are not needed.
Brushes Used to easily clean test tubes, cylinders and other
glassware.
Evaporating dish: Used to recover dissolved solids after
evaporation.
Petri dish: used to culture different types of cells, including bacteria
and other microorganisms.
Thermometer: A thermometer is an
instrument that measures temperature.
Improvisation is the process of producing or preparing teaching and
learning materials from readily available and locally cheap and used
materials.
Making laboratory equipment /tools/ from locally available
laboratory materials
Laboratory safety rules are principles or regulations governing
actions, procedures, intended to reduce risks in the laboratory.
Basic Safety Rules
Basic safety rules for laboratory conduct should be observed
whenever working in a laboratory. Many of the most common safety
rules are listed below.
1. No student may work in the laboratory without the teacher’s
supervision.
2. Carry out only the experiments assigned by the teachers.
3. Eating, drinking, and chewing gum are not allowed in the
laboratory.
4 Keep your work area neat and clean.
5. Tie back loose hair.
6. Do not taste or smell chemicals.
7. Never add water to concentrated acid solutions. Because the heat
generated may cause splashing.
8. Be careful not to touch your eyes or other body areas without
thoroughly washing your hands first.
9. Report all accidents or injuries (burn, cut, chemical splash,
electrical shock etc…)
10. Before leaving the laboratory, see that:
a. Your desktop and work area is thoroughly clean.
b. All equipment in drawer is complete and well organized.
c. Unplug electrical sockets, and switch off the light.
d. You wash your hands before leaving the laboratory.
Laboratory safety rules and procedures
Personal protective Equipment
Personal protective equipment (PPE) includes safety glasses,
goggles, face shields, gloves, laboratory coats, ear plugs, and
respirators. Personal protective equipment is carefully selected to
ensure that it is compatible with the chemicals and the process
used.
Chemical goggles
Shield the eyes against liquid or chemical
splash, irritating mists, vapors, and fumes.
Safety glasses or chemical goggles must be
put on before entering laboratory.
Laboratory Coats
 Shall be worn before handling
chemicals, and biological specimen.
 Shall cover the wearer to the knees.
Face Protection
 Face shields worn over safety glasses may be required for
certain processes.
Eye glass
Laboratory coat
Face mask
Hand Protection
 Gloves, especially, should be chosen carefully. They must be
resistant to the chemicals being used.
Hazard Symbols
A hazard is something that could cause: harm to someone, damage to
something or adverse health effects.
Hazard symbols are used on containers. They are used to:
 Indicate the dangers associated with the substance inside a
container.
 Give information about how to work safely with the substance
in the laboratory.
 Hazard symbols are designed to provide a warning, even if a
person cannot understand the writing that goes with them.
Hand protection (gloves)
Hazard Signs (Symbols)