engineering in relation to project cycle introduction to engineering notes

1. Examples of the Engineering Method in relation to the Project Cycle
A. Road Project
1. Requirement
There is poor road link between Katakwi and Moroto. There is need to upgrade this road
link so as to promote economic development in the region. This will be achieved through:
i. The integration of international trade through improved cross-country transit
ii. The improvement of access to markets and producer services for the development
of rural households
iii. The reduction of poverty through economic growth based on broad-based
agricultural development and the spatial distribution of that growth
iv. The promotion of exports
v. The provision of access to social services
2. Analysis
The analysis will include data collection with respect to the proposed road link as follows:
Traffic Survey – the number and types vehicles along the proposed route will be physically
counted by a team. This can be a day and night count for a period of one week or
more, depending on the circumstances. A moving observation count can be used to
determine traffic volumes at different locations along the route. This data will be used to
predict the lifetime axle loading on the planned road, based on an equivalency factor for
different types of vehicles. The design horizon may be 10 or 15 years. Non- Motorised
Transport (NMT) like bicycles will also be included in the traffic count.
Materials Survey – this will seek to sample and test in-situ materials on the existing or
proposed alignment and potential sources of construction materials in the vicinity, including
rock, gravels, sand and water. The tests that will be carried out include the Liquid Limit,
Plastic Limit and Plasticity Index Sieve Analysis, Compaction and California Bearing Ratio
including wetted and dry samples
Topographic Survey – this will seek to identify the existing and proposed routes that will
be used in the pavement and drainage design. A more detailed survey will be done on cross
sections of the proposed route.

2. Hydrological Survey – this survey will obtain records of the climate which include;
rainfall, river flows and temperatures. This information is required for the design of
drainage structures such side drains, culverts and bridges.
An Environmental and Social Impact Assessment will be also carried out and a Preliminary
Resettlement Action Plan.
At the end of this a Feasibility Study Report is produced.
3. Synthesis and Evaluation
This will include the Preliminary Design which can include the:
i) Pavement Design,
ii) Design of Hydraulic Structures and
iii) Cost Estimates
The Pavement Design will follow the Ugandan Road Design Manual or other design
standards, which may be the Kenyan Design Manual, the UK Transport Research
Laboratory (TRRL) standards or the American standards depending on the either the capital
costs or the life cycle costs.
In some cases, this will include strengthening of a subgrade, making an adequate sub- base,
road-base and including a wearing course.
In the Design of Hydraulic Structures, the design flood flows for the drainage structures
will first be estimated using either the rational formulae or TRRL formulae and the
hydraulic design will be done using the Manning equation.
Cost estimates of different alignment options and different pavement options will be carried
out.
The Preliminary Design includes the design report, the book of drawings, the bills of
quantities, the cost estimate and specifications
After the Preliminary Design is completed, it is submitted to the Client who evaluates it
and provides comments. Once these comments are incorporated it becomes the Final
Design.

3. The Final Design which are the tender documents consist of i) the book of drawings, ii) the
bills of quantities, iii) the specifications both general and special and iv) the forms of
security, which include the bid security, the performance security and the advance
payment guarantee.
The Final Design is now ready for execution.
4. Execution
The execution of a project of this kind is usually by the selection of a contractor, through
a competitive bidding process or by direct contracting.
In the competitive bidding method, tender documents are usually given to prequalified
contractors because this approach usually saves on time as opposed to post qualification,
which takes place after the bidding process.
Under prequalification, prospective contractors are prequalified based on specific criteria.
These criteria may include:
i) the legal and financial status ii) the experience of the firm iii) the qualifications
of key personnel and iv) equipment available.
i. Legal and Financial Status: these include certificate of incorporation /
registration, memoranda of association, audited accounts, recommendation from
bankers.
ii. Experience of the Firm: this includes the value and nature of contracts during the
last two years as a minimum.
iii. Qualifications of Key Personnel: this would include the education and experience
of the individual staff members categorized as management, technical and possibly
support staff.
iv. Equipment: the contractor should have adequate equipment for executing the
works on hand.
Post qualification is the same process but is done after contractors have submitted their
bids.

4. Contractors are required to submit bids within a specified time. Once they are submitted,
they are evaluated by a committee and the lowest evaluated bidder is usually selected to
execute the works.
The direct contracting method applies in situations where there is an emergency and there
is need to construct the facility quickly. This method of contracting usually requires
the approval of the National Procurement authority. If this method is to be used, there
will be need to select from the list of prequalified companies based on the past performance
in terms of timely execution and quality of the works.
Once a Contractor is selected, he will be supervised by the Client and the Consultant
until the works are completed and handed over back to the Client for operations and
maintenance.
B. Water supply and sanitation project for an Urban Area
1. Requirement
It is necessary to provide an improved water and sanitation system in Gulu Municipality
in order to improve the overall health of the affected community. The impact is felt
particularly among children and mothers who do most of the water collection in homes. For
the children, it would mean less time is spent on collecting water and more time can be
spent at school and other productive activities. Furthermore, repeated attacks of malaria
lead to stunted growth and poor intellectual development, which makes them less
competitive in national examinations and thus limits their progression through the
educational system and this continues to fuel, the cycle of poverty. For the mothers, it
would mean less time is spent collecting water and more time can be spent on more
productive activities such as adding value to crops. Furthermore, repeated attacks of
malaria lead to miscarriage in pregnancy and childbirth.
2. Analysis
A number of studies will be required which need to be incorporated in the feasibility
study. These include urban planning, population, socio-economic assessment, hydrology
and water resources, survey and mapping, materials and environmental impact assessment.

5. Urban planning
There is need to discuss the present land use activities and the plans for the future land use
based on structure plans for the urban centre.
Population
There is need to collect historical population data and make projections using the population
growth rate in order to determine the population to be served by the project.
There is need to determine the institutional population as well for markets, schools,
offices, hospitals and health centres, prisons, police and the army. Water demand
projections will be made based on domestic and non-domestic demand consumption
rates.
Socio- economic Assessment
There is need to establish the following:
i. Stakeholder’s attitudes to available water resources and sanitation requirements
ii. The status of household sanitation
iii. Establish income and expenditure levels of the population and therefore service
levels for water supply.
iv. Ability and willingness to pay for improved water and sanitation facilities (a
guideline for affordability is 5% of the income or expenditure)
v. The perception by stakeholders of the best arrangements for the scheme
implementation and future management
Hydrology and Water Resources
There is need to establish the available surface or groundwater resources regarding
their yield to meet the required demand. This will include the type of catchment, average
annual rainfall and seasonal variations, evaporation rates, recharge rates, water yield
and flood risk.
Survey and Mapping
Existing control points can be used to locate new GPS points for the sites, which are
then listed. Levelling results are obtained indicating the levels for the sewerage surveys.

6. Profiles are required for the:
i) raw water transmission main,
ii) water distribution main
iii) sewerage lines.
Topographic surveys are required for both the water and sewage treatment works layout.
Cross sectional surveys will be done at the proposed dam site.
The water supply and sanitation area will be mapped, clearly demarcating block maps,
the reticulation network, location of consumers and a complete data base of consumers.
Soils and Materials
The existing soils and their capacity to support the proposed structures are investigated.
These would include for a dam embankment, spillway and dam foundation. Borrow pits
and quarries will be identified within the proximity of the proposed dam site. Core drilling
will be done at cross sections for the proposed dam.
The objectives are to:
i) determine the soil profile and classify the subsoil
ii) determine the permeability characteristics of the soil and the strength parameters.
Financial analysis
This is required to determine;
i) the cost of water supply per m³ii) the cost of collection, treatment and disposal of
sewage per m³iii) revenue collections from billing to calculate iv) net present value
v) a sensitivity analysis
The factors that will, be considered will include the
i)design horizon, ii) base year and inflation, iii) discount rates, iv) economic lifetime v)
value of existing assets v i ) volumes of water and sewage, v i i ) number of connections,
viii) operations and maintenance costs and ix) economic benefits.
Institutional analysis
This will discuss the policy, regulatory and legal framework and if it is appropriate for
additional investments and what modifications need to be made.

7. Risk Assessment
These are factors that may cause failure or jeopardize the successful completion of a
project. Risk Management involves mainly two stages, risk identification and risk
mitigation.
Environmental Impact Assessment
The assessment would use checklists for water supply projects as well as NEMA
Environmental Impact Assessment Guidelines (1997) and Environmental Impact
Assessment Regulations (1998).
The different types of impacts may include:
i)erosion of access roads, i i ) permanent severance in land or change in land rights
arising from scheme activities, iii) impacts from operation and maintenance iv) socio-
economic impacts, v) water supply impacts vi) effects on areas around stand posts by the
people who collect water and v i i ) the do-nothing scenario.
An environmental mitigation plan will be developed for execution in the construction
phase.
3. Synthesis and Evaluation
Water Supply System
The state of the existing water supply system is to be clearly documented and possible
improvements are proposed. The components include:
i)the intake, ii)the pumping mains, i i i )the water treatment works, iv) alum dosing plant,
v) rapid gravity filters, vi) chlorination unit, v i i ) clear water tank, v i i i ) clear water
transmission main, i x ) storage reservoirs ,x)distribution network, xi) booster station and
x)service connections.
Sewerage System
The possible sites and method of treatment are determined based on technical and
economic criteria.

8. The sewer diameters, length, material of the pipes and the size of the sewage ponds are
determined by the sewage inflows, which are based on the population to be served. Where
necessary a sewage pump will be included in the system
A method of reusing the waste content of the sewage effluent along with the fertility
value of the organics, for agricultural and aqua cultural purposes will also be developed.
An Operations and Maintenance Strategy would be designed, which would include routine
maintenance of the ponds.
On- Site Sanitation
Proposed technologies will include pit latrines, ventilated improved pit latrines, pour flush
latrine, ecological sanitation toilet and septic tanks.
Households should provide their own sanitation, but this is not the case because of
competing demands for their income. Coverage can be improved through;
i) encouraging demand
ii) improving demand and good practice through education,
iii) improving supply through household services
iv) improving institutional effectiveness
v) through microfinance institutions.
Public facilities will be provided for public places such as markets and taxi parks.
The preliminary design will include a design report, specifications, a book of drawings
and bills of quantities. These will be submitted to the Client before the Final Design and
Tender Documents can be prepared.
4. Execution
This will be done by a Contractor and the processes are similar to those discussed in the
Soroti – Moroto Road Project.

9. C. Building Project
1. Requirement
It is necessary to put in place building infrastructure that will support tourism development
in the National Parks. In particular it will provide accommodation for tourists
2. Analysis
Settlement Planning
In laying out the settlements, the buildings have to meet the social and cultural norms of
the residents and address the levels of privacy.
Survey and Mapping
It is necessary to carry out a location (cadastral) and topographical survey of the area
Building Design Concept
The building design concept needs to take into consideration the specifications of the
client and space requirements by the users in addition to the specific nature of the
conservation area.
Materials Design
The development of a workable, cost-effective sustainable concept has to take into
consideration the following:
i) geological conditions
ii) availability of basic construction materials and
iii) availability of skilled and casual labour.
Environmental Impact Assessment
The NEMA Guidelines (1997) and Regulations (1998) will be used and an Environmental
and Mitigation Plan developed.
3. Synthesis and Evaluation
The preliminary design will include:
i) foundation, ii) walls, iii) roof structure, iv) doors, windows and ventilators v) structural
design and vi) electrical and mechanical design.

10. The foundation, walls, roof structure, doors, windows and ventilators will be designed
according to the space requirements and appropriate standards.
Structural Design can be carried out in accordance with BS 8110 Parts 1,2 and 3, where
both first principles and computer aided design (CAD) techniques should be employed.
Electrical and Mechanical Design will be done for the electrical installations and water
supply, sanitation and air conditioning systems respectively using the respective British
Standards. Alternative sources of power and water supply will also be considered.
Specifications and Bills of Quantities will also be included.
The Client will comment and a Final design and Tender Documents will be produced.
4. Execution
This will be done using the same procedure as for the Soroti- Moroto Road Project.

11. D. A micro hydro power project
Requirement
There is need to provide power from clean renewable energy through the design and
construction of a decentralized power network in order to promote agro-processing,
small scale industries, social services like education, healthcare and the provision of potable
water. The impact would be felt more among women and children who are responsible for
the collection of firewood.
For the children, it would mean less time is spent on collecting firewood and more time can
be spent at school and other productive activities. Furthermore, repeated exposure to
kitchen smoke may lead to respiratory diseases such as bronchitis and pneumonia which
can lead to frequent absence from school resulting in poor performance in national
examinations and thus fuelling the cycle of poverty. This can also mean more deaths
meaning an increase in child mortality. For the mothers, it would mean less time is spent
collecting firewood and more time can be spent on more productive activities such as
adding value to crops and fewer smoke related respiratory diseases. The availability of
power would mean more opportunities for learning in the evening and may lead to less
procreation.
Analysis
A number of studies will be required which need to be incorporated in the feasibility
study. These include urban planning, population, socio-economic assessment, hydrology
and water resources, survey and mapping, materials and geology and environmental impact
assessment.
Urban planning
There is need to discuss the present land use activities and the plans for the future land use
based on structure plans for the urban centre.
Population
There is need to collect historical population data and make projections using the population
growth rate in order to determine the population to be served by the project. There is need
to determine the institutional population as well for markets, schools, offices, hospitals and

12. health centres, prisons, police and the army. Electrical power demand projections will be
made based on domestic and non-domestic demand consumption rates.
Socio- economic Assessment
There is need to establish the following:
i. Stakeholder’s attitudes to available energy requirements
ii. The status of household energy supply
iii. Establish income and expenditure levels of the population and therefore service
levels for energy supply.
iv. Ability and willingness to pay for improved energy facilities (a guideline for
affordability is 5% of the income or expenditure)
v. The perception by stakeholders of the best arrangements for the scheme
implementation and future management
Hydrology and Water Resources
There is need to establish the available river flow to meet the power demand. A flow
duration curve will provide the 90%, 95% and 99% reliable flow. Other important
parameters are the average annual rainfall, seasonal variations, evaporation rates, water
yield and flood risk.
Survey and Mapping
A topographical survey will be done for the catchment in order to determine the level of
impoundment. Profiles are required for the:
i)spillway and flood control gates, ii) the silt basin and forebay tanks, iii) penstock,
iv) turbines and generators, v) the sub-station, vi) the power transmission mains,
vii) transformers and viii) the distribution networks.
Cross sectional surveys will be done at the proposed dam site.
The power supply area will be mapped, clearly demarcating block maps, the reticulation
network, location of consumers and a complete data base of consumers.

13. Materials and Geology
The existing soils and rocks and their capacity to support the proposed structures are to be
investigated. These would include for dam embankment, spillway and dam
foundation. Borrow pits and quarries will be identified within the proximity of the
proposed dam site. Core drilling will be done at cross sections for the proposed dam.
The objectives are to:
i) determine the soil profile and classify the subsoil
ii) determine the permeability characteristics of the soil and the strength parameters.
Financial analysis
This is required to determine; i) the cost of power per kWh ii)) revenue collections from
billing to calculate Net Present Value iii) a sensitivity analysis. The factors that will, be
considered will include the i) design horizon, ii) base year and inflation, iii) discount
rates, iv) economic lifetime v) value of existing assets vi) power generated, vii) number
of connections, viii) operations and maintenance costs and ix) economic benefits.
Institutional Analysis
This will discuss the framework for managing the power supply scheme taking into
account the required technical and management capacity.
Risk Assessment
These are factors that may cause failure or jeopardize the successful completion of a
project. Risk Management involves mainly two stages, risk identification and risk
mitigation.
Environmental Impact Assessment
The assessment would use checklists for hydropower projects as well as NEMA
Environmental Impact Assessment Guidelines (1997) and Environmental Impact
Assessment Regulations (1998).
The different types of impacts may include: i) erosion of access roads, ii) permanent
severance in land or change in land rights arising from scheme activities, iii) impacts
from operation and maintenance iv) socio- economic impacts, v) loss of water to
downstream users v) habitat loss and vii) the do-nothing scenario.

14. An environmental mitigation plan will be developed for execution in the construction
phase.
Synthesis and Evaluation
The preliminary design will include the design for: i) the dam, ii) spillway and flood
control gates, iii) penstock and surge tanks iv) the silt basin and forebay tanks, v)
turbines and generators, vi) the sub-station, vii) the power transmission mains, viii)
transformers and xi) the distribution network.
There will separate specifications for electrical and mechanical components.
Execution
This will be executed as in the road project except you may have separate contractors for
the electrical and mechanical works.

15. HISTORY OF ENGINEERING
Engineering was not spoken into existence by royal decree or caused by legislative fiat. It
has evolved and developed as a practical art and a profession over more than 50 centuries of
recorded history. In a broad sense, its roots can be traced to the dawn of civilisation itself,
and its process parallels the progress of mankind.
ENGINEERING IN THE EARLY CIVILIZATION
THE MESOPOTAMIANS
Significant engineering achievements must be credited to the dwellers of Mesopotamia, the
land between the Tigris and Euphrates rivers, currently the country of Iraq. The land of
Mesopotamia was open to attack from the north, east, and west, and its history is a confused
record of conquests and occupations by neighbouring people. The most prominent rulers of
ancient Mesopotamia were the Babylonians and the Assyrians.
In this area, the wheeled cart is said to have first appeared.
In southern Mesopotamia, at the beginning of recorded history, the ancient and mysterious
Sumerian people constructed canals, temples, and city walls that comprised the world’s first
engineering works.
Records show that an angle measuring device called the astrolabe was being used for
astronomical observations. This instrument, which consisted of a graduated circle and
sighting arm, was being used on the 60-unit numerical system used by Mesopotamians. That
system has been retained in time and angle measurements to the present day.
The most unusual class of structure left by the Mesopotamians was the ziggurat, a temple
tower built in honour of their gods. The ziggurat was a terraced pyramid of brick with
staircases, setbacks, and a shrine or chapel at the top. The tower of babel mentioned in the
Old Testament is believed to have been this type of structure.
Hammurabi, the great king who ruled Babylonia for 43 years (circa 1850 to 1750 B.C.)
compiled a comprehensive new code of law that bears his name. This famous code provided
penalties for those who permitted poor construction practices and is considered to be a
forerunner of today’s building codes. The code of Hammurabi provided an important
message dealing with quality assurance and professional responsibility and exacted
extremely severe penalties for its breach. It read:

16.  If a builder builds a house for a man and do not make its construction firm and the
house which he has built collapse and cause the death of the owner of the house-that
builder shall be put to death.
 If it causes the death of the son of the owner of the house-they shall put to death a
son of the builder.
 If it causes the death of the slave of the owner of the house-he shall give to the owner
of the house a slave of equal value.
 If it destroys property, he shall restore whatever it destroyed, and because he did not
make the house which he built firm and it collapsed, he shall rebuild the house which
collapsed at his own expense.
 If a builder builds a house for a man and do not make its construction meet the
requirements and a wall falls in, that builder shall strengthen the wall at his own
expense.
It is not surprising that the people who populated the valleys of the Tigris and Euphrates
developed significant irrigation and flood control works. Today, in Iraq, evidence of
abandoned canals can be traced by lines of embarkments, lakes, and streams.
During the reign of King Sennacherib, the Assyrians completed (circa 700 B.C) the first
notable example of a public water supply. They built a 30-mile-long feeder canal bringing
fresh water from the hills of Mount Tas to the existing Khosr river, by which water flowed
an additional 15 miles into Ninevah.
THE EGYPTIANS
In ancient Egyptian civilization, experts in planning and construction emerged. These
engineering forerunners held top positions as the trusted advisors of the Egyptian kings. The
man who held this position was a general construction expert who was known as the king’s
“chief of works”.
These ancient engineers/architects practiced the earliest known form of surveying, developed
effective irrigation systems, and built remarkable edifices of stone. The annual flooding of
the Nile created a need for re-establishing land boundaries. To perform these surveys,
Egyptian engineers used sections of rope that had been soaked in water, dried, and then
coated with a wax material to insure constant length. They may have also used primitive
surveying instruments, but none has been found.

17. It is known that as early as 3300 B.C., the Egyptians developed and maintained an extensive
system of dykes, canals, and drainage systems. A great mass of people populated the narrow
fertile valley of the Nile, and irrigation works were needed to maintain the large population
and exploit the skill of agriculture. The river also served as the principal means of
transportation because horses, wheeled vehicles, and roads were unknown in Egypt until
about 1785 B.C.
The engineers of ancient Egypt sought to build the tallest, broadest, and most durable
structures the world would ever see. Their palaces, temples, and tombs were designed as a
symbol of triumphant and everlasting power.
The best-known works of the Egyptian builders are the pyramids. The first pyramid was the
step pyramid at Sakkara, built by Imhotep as a burial place for the ruler Zoser in about 2980
B.C. The design of pyramids evolved from tombs known as mastabas. The ancient Egyptians
regarded a King’s tomb as a house where he actually lived after death, and some of the more
elaborate mastabas contained several rooms and storage cells where food and weapons were
placed in close proximity to the dead ruler and his family. Zoser’s step pyramid is actually
six mastabas.
Three pyramids still stand on the west bank of the Nile River at Giza as remainders of the
outstanding engineering skills of the Egyptians. The largest pyramid known as the Great
pyramid or the pyramid of Cheops, is approximately 481 feet high, and its base is close to
13 acres.
Herodotus, the Greek historian who visited Egypt in the fifth century B.C., reported that it
took 100,000 men 20 years working in three-month relays to build the pyramid.
THE GREEKS
From about 2000 BC, Indo-European invaders moved down to the land that is known as
Greece. The Greeks were part of civilization and therefore knew a lot about it. They started
with the ancient times, then the Bronze Age when the existing way of life started to break,
and later the Iron Age, which brought with it iron weapons and iron agricultural implements.
Ancient Greece provided the world with some of the greatest philosophers; most famous of
these were Plato (427-347 BC), Aristotle (469-399 BC) and Plato’s teacher Socrates (469-
399 BC).

18. The Greeks were the first to develop a scientific imagination; the ancient scientists like the
Babylonians simply stated laws but the Greeks asked why things were as they were. Greek
science grew very quickly with all the main ideas formed in a matter of 150 years.
Beginning about 600 B.C., the Greek way of life and thought became dominant in the eastern
Mediterranean area. The Greeks are best remembered for their abstract logic and their ability
to theorize and to synthesize the knowledge of the past. Their advances in art, literature and
philosophy were great, tending to overshadow their contributions to engineering. They
tended to focus mainly on theory and placed little value on experimentation and verification
and on practical application.
Nevertheless, the Greek architecton made the first notable advance toward professional
stature. He was recognized as a master builder and construction expert with knowledge and
experience beyond the scope of the average citizen.
The Greek peninsula was cut up by mountain ranges that land communication was difficult.
The Greeks turned to the sea to become the first great harbour builders. Herodotus described
a great breakwater or mole that was constructed to protect the harbour at Samos. The
breakwater was 400 yards long and was built in water 120 feet deep. This represents the first
recorded construction of an artificial harbour, and it was to become a prototype in harbour
planning even into modern times.
The Greeks’ interest in navigation later led to the building of the first light-house in the
world, the Pharos at the port of Alexandria. This 370-foot-high structure, built about 300
B.C., was known as one of the seven wonders of the ancient world.
Another great work built on the island of Samos was a 300-foot-long tunnel cut through a
900-foot hill under the direction of the architecton Eupalinus of Megara. The main tunnel,
which was hand-chiselled through solid limestone, was about 5.5 feet in width and height.
At the bottom of the main channel, a trench was cut 30 feet deep and 3 feet wide. In this
trench, water was brought through clay pipes to the city.
During the golden age of Greece, the ruler Pericles undertook a huge building program
designed to make Athens the most beautiful city on earth. He retained the services of leading
artists and building experts of the time to build temples, shrines, and statues on the Acropolis,
the flat-topped rock over looking the city. The ruins of these works today provide one of the
world’s most remarkable sights.

19. The builders of the Greek temples must have used timber frames and manual hoists that were
equipped with capstans and pulleys similar to those used in modern times. By their use of
columns and beams, the designers showed a level of structural understanding not
demonstrated by builders of the past.
Founders of Modern Science
1. Pythagoras
Pythagoras (570-500 BC) was a Greek philosopher who developed the idea that mathematics
was concerned with nature; previously, little thought was given to the connection between
the two. He thought it unimportant to discover basic components out of which the world was
made; instead, he claimed that measurement or number was the real key to understanding
and he made several striking discoveries about numerical properties of things.
He, however, did not produce the Pythagorean Theorem; it was known many thousands of
years before by the Babylonians who had tables giving the lengths of the sides of the so-
called Pythagorean right-angled triangles. Nor did he produce the proof of it, for this was
done hundreds of years later; what he did was announce the theorem and considered it a
great mystery _ that the square on the hypotenuse of a right-angled triangle was equal to
the sum of the squares on the other two lengths, irrespective of man or anything else.
2. Aristotle
The Greek philosopher, Aristotle was one of Plato’ most famous students, and he was
teacher to Alexander, the son to King Phillip; by that time, Greece had been conquered by
Macedonians. Aristotle contemplated the issues of motion (dynamics) and equilibrium. He
considered rest to be the natural state of things on earth and that everything was made of a
mixture of what he called the elements‟- earth, water, fire and air”. Each of these elements
had a natural resting place and when disturbed would always return to this natural
resting place. He went on to conclude that heavier objects would fall faster than lighter
ones.
3. Archimedes
The Greek philosopher Archimedes was the first to propound on the principle of flotation.
This principle implies that for a body to float, the forces acting on it must be in equilibrium.

20. That is to say, its weight acting downwards and upthrust, which is equal to the weight of
the fluid displaced, must balance out. If the latter is greater than the former, it sinks. If the
reverse is true, it rises.
4. Hippocrates
The first truly scientific doctor, some of whose writings have come down to us is
Hippocrates of Cos who was born about 460 BC. It is the theory and practice of
Hippocrates that underlies modern medicine. His theory stated that every disease is subject
to natural law just like everything else and should therefore be carefully observed; and that
since all bodies have a natural tendency to recovery the proper duty of medicine is to seek
the best ways in which to help it. Doctors today still sometimes take the “Hippocratic
Oath” when they qualify.
5. Democritus
About the 5th
century BC, some scientists who were called the atomists, led by Democritus
made this assertion, “We see change and movement therefore there must be change and
movement”. They concluded that the world was made not of unmoving spherical masses-
as Parmenides had suggested- but millions of tiny atoms that could change position among
themselves and thus make up new things. This became the basis of atomic theory that
was later propounded upon by Dalton, and has given us an appreciation of the atomic world.
Science has since proven Democritus right.
Democritus, as learnt from Leucippus, held the view that numbers applied to actual
things. Democritus took a very rigid view saying that there were hard, unbreakable,
uncuttable things _atoms_ and that by arranging them in various geometrical figures, you
could produce all the various appearances that were seen. The atoms, he said, of course could
not stand still, they moved around forming new combinations.
The Legacy of the Classical World
From about 100AD until almost about 1200, the sciences did not even reach the Greek
standards. Remarkable developments were made in astronomy such as actual
computational astronomy, especially in Egypt. Hipparchus made star catalogues, eclipses
were studied, and the first models of the solar system made. These improvements became

21. the basic guidelines of the motions of the stars and the planets for future centuries and
lead great discoveries of the Renaissance. In 1540, Archimedes works were translated to
Latin for the first time, and read by competent mathematicians. As a result, this led to the
great revolution, among others. Much of the other sciences of the Ancients were preserved
in books; but because astronomy was needed to chart the planets, it was handed and passed
on.
However, these scientific developments came to a standstill due to war; Greece was under
siege by Carthegians. As a result, Archimedes was called as a scientific advisor, using
mirrors and other devices to burn up enemy ships, although they lost in the battle.
Medieval Times
The medieval times were an intermediate period, vital for the development of sciences
preparing for the Scientific Revolution. During this time, science was no longer taught,
and in the west, this period was referred to as the Dark Ages. Apparently, what was
happening in Europe was people wondering; the Franks were getting into France, the
Angles were getting into England, the Burgundians, the Lombard and other tribes were
wandering about all over Europe, the Vandals getting into Africa, the Huns into Eastern
Europe. As a result of these migrations, much of the civilizations disappeared although
there was some degree of continuity of urban life.
THE ROMANS
The most famous engineers of antiquity, the Romans, devoted more of their resources to
public works than did their predecessors. With cheap labour, including thousands of slaves
and abundant raw materials, they built arenas, roads, aqueducts, temples, town halls, baths,
and public forums.
Scholars divide Roman history into two main periods: the republic and the empire. The
republic was an age of conquest and exploitation of Rome’s extensive colonial possessions,
a time when Roman engineering achievements were confined largely to Italy. The empire
was a relatively peaceful period in which public works were extended into the colonies;

22. remains of some of these engineering facilities can be found today in Spain, France, North
Africa, and the Near East.
In contrast to the Greeks, the Romans were practical builders who relied more on experience
than on mathematical logic and science. Their works were simple in design yet impressive
in scale and bold in execution. By and large their works emphasized function rather than the
artistic or aesthetic.
Roman builders are credited with making significant contributions to engineering, which
include developing improved methods of construction, discovering and using hydraulic
cement, and devising a number of construction machines such as pile drivers, treadmill
hoists, and wooden bucket wheels. The latter machines were used for dewatering mines and
construction sites.
One of the famous Roman engineers was Vitruvius (a military engineer), who served under
Julius Caesar, and wrote the acclaimed book De Architecture. The contents of his book give
advice on the construction of buildings, finding water and testing rainwater, methods of
levelling, and waxing and waning of the moon.
Some of the most famous of Roman engineering works are briefly described below:
1) The Circus Maximus was a race course where games and contests were held. It is
believed to have been either built or greatly enlarged by Tarquinius Priscus, an
ancient king of Etruscan and Greek ancestry who ruled Rome in the sixth century
B.C.
2) The Appian Way was the first and most famous link in a road network that radiated
from Rome. Named for Appius Claudius, the Censor of Rome in 312 B.C., the road
was noted for its direct alignment, high embarkments, and superior pavement
structure. The Roman empire had 80,000 Km of major roads. Although the
engineers had to know what the craftsmen were producing, they did not have to
acquire the skills themselves.
3) Aqua Appia, also named for Appius Claudius, was the first major aqueduct built in
Rome. It was a low-level, largely underground work built in a tunnel or by cut-and-
cover construction.
4) The Pantheon was a temple of extraordinary stateliness. Agrippa, a brilliant engineer
and the adopted son of Augustus, built the Pantheon circa 17 B.C. It suffered two

23. fires and was rebuilt by Hadrian who ruled during the period A.D. 117-138. The
internal diameter of the Pantheon is equal to its height of 141 feet. It is crowned with
a coffered semi-spherical concrete vault. Preserved to the present day, the Pantheon
embodies Rome’s most imaginative engineering works.
5) The Alcantara bridge, built in Spain by the engineer Gaius Julius Lacer in A.D. 98,
is still in use. It has six arches of dry stone and a total length of 600 feet. The roadway
is 175 feet above the river.
6) The Pont du Gard was part of an ancient aqueduct that supplied water to Nimes in
south France. Built under the direction of Agrippa during the reign of Augustus (circa
27 B.C. to A.D. 14), this imposing structure was built of dry masonry construction,
except for the water channel on top. It is about 160 feet high, and its larger arches
have a span of approximately 80 feet.
7) The water wheel, the Romans were also instrumental in spreading the use of the water
wheel throughout Europe. For example, a slave working for 10 hours could grind
about 40 kilogrammes of corn, whereas two water wheels in series could grind 28,000
kilogrammes in a 10-hour day and supply sufficient flour for 80,000 people. The
potential for water power was appreciated in Northern Europe where there was a
plentiful supply of water throughout the year.
8) The Roman medicine, the greatest of the Roman physicians is perhaps Claudius
Galenus who became physician to Emperor Marcus Aurelias (AD 130-200) and his
writings were to influence medicine for some fifteen centuries. His theory was
basically that every created part in the body had a purpose for being created by
God and that by careful study it was possible to fully understand the body.
Fall of the Roman Empire
The geographical extension of science was then continued later by the Arabs. There
was a great jehad against the Roman Empire which was started by the Arabs, who were
successful in both conquest and governance. A characteristic of the fall of the Roman
Empire was the decline in engineering works. Western Europe had however, remained
backward, in the sense that because it was at the edge of the Roman Empire, it benefited
least from Roman civilization, and consequently was the least developed.

24. ARAB SOCIETY
After the fall of the Roman Empire, the Byzantine Arabs became the custodians of learning
until the Renaissance period- they translated into Arabic the works of Aristotle, Euclid,
Archimedes, Hero of Alexandria, Galen and Ptolemy. People adhered to the Mohammedan
rule easily because they found it fairer and easy as compared to the previous unpopular
Roman and Greek rules. All the Syriac translations of the Greek works were translated
into Arabic, and, by that time, there were many Arab scholars who were learned in the
Greek language; Arabic knowledge was thus added to the Greek knowledge. The main
contribution made was the Arabic Numerals. The Arab scholars used to travel from
Morocco to Peking and back; this resulted into a geographical extension of science, greater
than that during the time of Alexander.
During the Arab period, science was spread in an organized manner - through universities.
Initially, in Greece, there had not been any universities, only schools where philosophers
taught a few men who attended and it was strictly a private affair. The Museum on the
other hand, was a research institution, not a teaching institution.
Arabic astronomy
The Arabic attitude was to examine the works of the Ancients and make any corrections
and improvements where necessary, which they did superbly. They dealt chiefly with
astronomy, making very accurate astronomical observations with much bigger
apparatus.
The Arabs made astronomical tables, which were later taken over by the Christian crusaders
who drove the Arabs out of Spain.
Arabic medicine
The Arabs did a great deal in chemistry unlike in the other sciences; the Greeks did not
have anything in chemistry The Persian Avicenna wrote a medical encyclopaedia at the
beginning of the 11th
century that was still a chief medical text book by the beginning of
the 17th
century both in the east and in the west. Much of the medical work written in
Arabic was the work of Jewish doctors such as Isaac Israili, Rabbi Moses ben Maimon and
Constantin. In the13th century a number of new medical schools and universities were

25. started and the habit of making and keeping “case-histories” of patients was started some
of which were of great interest to medical men of later generations.
Optics
Mohammedan science made a great advance on that of the Greeks in the field of optics,
which was largely a by-product of medicine. The Greeks had the mirror and they knew
that it would focus but they did not have lenses. On the other hand, Arabs had the lens
which they used to improve the vision of old men by the use of spectacles.
In conclusion, the Arabs saved a great deal of Greek contributions in physics. In chemistry
and medicine, they made great reformations, and in physics, they added information on
optics and magnetism.
THE CHINESE
The Chinese reinforce how science has its origin in the social needs and activities of
man. The Chinese had, and do still have, numerous gods that they honoured in various
festivals throughout the year intended to ensure good health, plentiful harvests and
blessings in all areas of their lives. Based on these beliefs, there were philosophers in China
who played a special part in society. They were scientific advisers, so to speak, who made
a living by staying at the court or the city, advising the ruler or government what they
should do in various circumstances according to omens (derived from consulting the stars
and the gods).
There were also a number of cultural rituals concerning the burial of their dead. The
Chinese used to spin the spoon on the geomancer’s table and the direction it finally pointed
was the direction to bury somebody _ a form of astrology. In this way, the Chinese were
the first to discover the relation of a magnet with direction, accidentally, when they
realized that the spoon made of lodestone always pointed south on the geomancers
table while spoons made from other materials showed variable results. From this, the
compass was gradually born to improve on navigation.
The origin of chemistry was also connected with death rituals where the Chinese learnt
that the substance (mercury sulphide) which they rubbed on their dead to imitate blood

26. formed two other substances when heated: a yellow material which burnt (sulphur), and
a shiny metallic material which ran (mercury). It was from this that chemistry grew and
spread.
The other major invention to come out of China at the time was the new horse harness.
The harness was first developed in China in form of a stirrup, which enabled the horse
rider to shoot his arrow both backwards and forwards as he sat in the saddle. This
greatly improved military warfare, and later agriculture, when it was realized that two
horses could plough a slope which was initially done by eight oxen. This led to an
improved production of corn.