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Introduction
Welcome to the world of science and world of Physics. You already have learnt a lot about science in primary school. Therefore, the primary science knowledge, skills and attitudes will be the foundation of this course. Be prepared to acquire more interesting knowledge, skills and attitude about science in this course. We will begin this course by reviewing our understanding of what is science and how scientific knowledge, skills and attitudes are developed. Then, we will explore the different branches of science and the place of Physics within these branches. In so doing, you will be able to increase our understanding of science and Physics.
Science in action
What is science?
Activity 1.1 : To describe science
(Work in groups)
Conduct a research from books or Internet on what science is and its branches.
In your research, also find out the approach used in scientific study.
Present your findings to your class.
The word science is derived from the Latin word ‘scientia’ which means knowledge attained through study and practice.
Thus, science refers to a systematic study that uses observation and experimentation to describe and explain natural phenomena. The word also refers to the organised body of knowledge people have gained using a system of observation and experimentation.
This system of study is called the scientific method or scientific investigation.
The purpose of science is to produce useful models of reality which are used to advance the development of technology, leading to better quality of life for man and the environment around him. There are many branches of science and various ways of classifying them. One of the most common ways is to classify the branches into social sciences, natural sciences and formal sciences.
Social sciences deal with the study of human behaviour and society. Examples of these are psychology and sociology. Natural sciences deal with the study of natural phenomena, for example lightning, motion, earthquakes all which can be observed and tested. Examples of these are physics, chemistry and biology. Formal sciences deal with mathematical concepts and logics. An example of this is mathematics.
Physics as a science and its characteristics
At Primary level science, we learnt that matter is anything that has weight and occupies space. Physics is a natural science that is concerned with the study of matter and natural forces. In this study, it employs a scientific approach. The approach is based on systematic experimentation through careful measurements and analysis. Conclusions are drawn from the analysis.
These conclusions are tested to find out if they are valid. It is from the conclusions arrived at, that general laws and principles are stated. As such physics qualifies as a science.
History of Physics
Physics was born by the first people who started asking the ‘why’ question. For example, why is there day and night? Why do objects fall downwards instead of going upwards when released in air? Why, why, why why? This question always requires that you give an explanation.
The first people to attempt to answer this question were the Greeks who started doing this before 400 BC (Before Christ). By about 320 BC one of the greatest physicists of the day, Aristotle had developed a comprehensive explanation of motion by 1543 AD (Anedomino means After Christ), Nicolus Copernicus had explained that the earth goes round the sun and not the other way round.
By 1727 AD, Isaac Newton had explained why objects always fall towards the earth. By 1940, Albert Einstein had explained how nuclear energy can be gotten from the centre of the atom. Throughout history, Physics has continued to advance while making invaluable contributions to development of science and technology.
Importance of Physics
1. Physics provides the basic foundation on which other sciences are built. We have already mentioned that Physics enables us to understand the basic components of matter and their mutual interactions. This helps in explaining natural phenomena such as properties of matter. For instance, the knowledge of capillarity in liquids which is learnt in Physics is used to explain the rise of water in plants; pressure difference concept in liquids is also used to explain blood circulation in animals etc.
2. Knowledge and skills learnt in Physics find application in many areas of our daily lives. For example, proper use of household appliances such as refrigerators, iron boxes, television sets, replacing blown-up electric bulbs or fuses all require the knowledge learnt in Physics.
3. Knowledge in Physics helps in the acquisition of career of well paying jobs. The most obvious careers are in the field of engineering which include: civil, electrical, mechanical, agricultural, chemical, computer engineering etc.
Other careers are in the fields like meteorology, computer science, laboratory technology, surveying, geology and astronomy. Besides, one may become a Physics teacher in secondary school, college and university. Physics is also useful to doctors, nurses and other science based careers.
4. Technical instruments and equipment provided by Physics find application in almost every area of research. For example, meteorologists make use of instruments such as thermometers, barometers, among others developed by physicists. In medical laboratories, Physics principles and equipments such as electric microwaves are used in carrying out research on HIV and AIDS and other diseases
Branches of Physics
Physics is a wide body of knowledge which is studied under several overlapping branches. The following are the major branches of physics:
1. Electromagnetism: is the study of the interaction of electrical and magnetic fields. This has lead to development of useful electronic devices such as loudspeakers, electricity generators, telephone receivers and electric bells among other devices.
2. Mechanics: is the study of the action of forces on objects and motion. The knowledge of mechanics has lead to development of many motion related objects including vehicles, planes, ships, trains etc that have made our movement from one place to other faster and easier.
3. Thermodynamics: is the study of the relationship between heat, other forms of energy and work. The knowledge of thermodynamic is applied in making thermos flask, refrigerators, car engine radiators and air conditioners among other devices.
4. Optics: is the study of the behaviour and physical properties of light. This has lead to development of various optical devices like the lenses that are used in cameras by people with eye defects, projectors, microscopes, telescope, f ibre optics among others.
5. Acoustics: is the study of sound and sound waves. This study has been an instrumental tool in the development of various musical instruments like guitars, drums and pianos among other devices.
6. Electronics: is the study of the flow of electrons, generally in a circuit. It has led to the development various telecommunication devices like television, radios, computers, amplifiers and mobile phones among others.
7. Geophysics: is the study of the substances that make up the Earth and the physical processes occurring on, in and above it. The knowledge gained has made it possible to predict, measure and analyse the magnitude of natural phenomena like earthquakes and tsunamis.
8. Atomic Physics – is the study of the structure of the atom, its energy states and how it interacts with other particles and with magnetic and electric fields. This has lead to great milestones in the study of the chemical properties of matter. This has lead to generation of useful atomic energy and atomic bombs.
9. Nuclear Physics - is the study of the physical properties of the nucleus of atoms. This has led to the generation of nuclear energy which is reliable, relatively cheap and makes minimal pollution to the environment.
10. Astronomy: is the study of the universe, the celestial objects like sun moon, planets and stars that make up the universe, and the processes that govern the lifecycle of those objects. The discoveries made through astronomy go along way in satisfying our curiosity of the world we live in. The study has aided the setting up of communication satellites and the development of devices such as Global Positioning System (GPS) that are key in locating points on the earth’s surface.
Physics and other subjects
1. Chemistry mainly deals with the study of salts, acids and their reactions. For a physicist to understand the working mechanism of chemical cells, help is sought from a chemist. On the other hand, the reasons behind the various colours observed in most of the chemical reactions are explained by a physicist. Petroleum products are dealt with by the chemist, but the transportation of such products make use of the principles of physics.
2. In Biology, the study of living cells and small insects by a biologist requires magnification. The concept of magnification using simple or compound microscope is a brain child of a physicist. A good physicist needs to have good health.
A biologist will assist a physicist in the awareness of the following:
(a) A balanced and nutritive diet.
(b) Some simple physical exercises to keep fit.
(c) The various bacteria and viruses normally found in one’s blood system e.g. malaria, HIV, etc.
(d) The possible preventive measures in dealing with people who have been infected with diseases such as small pox, HIV and AIDS, etc.
(e) Effects and dangers of drinking excess alcohol, drug abuse, etc.
3. In Geography, weather forecast, a geographer uses a barometer, wind gauge, etc. which are instruments developed by a physicist.
4. In Agriculture, the water sprinkler, insecticide sprayer, etc. make use of the principles developed by physicists.
5. In History, the determination of age fossils by historians and archaeologists use the principle developed by physicists.
6. The theatrical setup, the audio and visual arrangements are the creations of physicists.
7. In games and sports, accurate measurement of time, distance, weight, etc. uses instruments developed by physicists.
Career opportunities in Physics
From Activity 1.4, you should have learnt that Physics, being a practical subject has many applications. These applications lead to diverse career opportunities depending on one’s skill and aptitude. The most promising area of job opportunities is in engineering and technology. Some of the careers one can fit in after studying Physics include: laboratory technology, mapping and surveying, civil engineering, electrical engineering, mechanical engineering, instrumentation technology, meteorology, electronics and telecommunication engineering, architecture, environmental engineering, aeronautical engineering, etc. Apart from engineering, pure sciences such as physics, geology, astronomy, astro-physics, etc. also offer suitable and promising careers. In the application of medical physics, there are career openings in radiology, ultra-sound scanning, medical sports, optometry, etc. In education, one can be a school teacher, university lecturer or a researcher. Therefore, a successful physics student can always find a suitable career opportunity.
Fig. 1.2 shows an electrical engineer at work.
Electrical engineer at work in Kawempe
Physics, society and technology
Physicists search for reliable information and then organise it into fundamental laws and principles. On the basis of these laws and principles, the engineers and technologists design and develop devices and appliances, that make our living more comfortable. For example, windmills make drawing of water from deep wells easier (Fig. 1.3).
The advancement of technology has led to the manufacture of computers, motor cars, aeroplanes, communication satellites, etc. Fig. 1.4 shows a communication satellite dish.
These advancements have improved our lives greatly since we can nowadays know what is happening around the world within seconds.
Indeed the world has become a global village. In addition to the above, it is important to note that physics has played a very vital role in:
Transport where high speed electrical trains larger and more fuel efficient marine vessels (e.g. ships), faster and safer automobiles have been developed.
Manufacturing sector where labour efficient robots and other gadgetry have been developed.
Medicine where development of better equipment in surgery and use of safer diagnostic techniques (such as Magnetic Resonance Imaging (MRI) have been developed.
Recreation and sporting where better equipment for recreation and training are continuously being developed.
Physics continues to play an invaluable role in all activities that relate to energy and its interaction with matter. The principles and laws of physics continue to be used in all areas of human activities such as engineering, medicine, transport, food processing, communication and many other areas. Here is a list of some of the milestones of advancements that have been achieved by application of physics:
- Computers - Digital video - The internet
- Jet engine - Artificial satellites - Nuclear energy
- GPS - Digital sound - Solar power
- TV - Space craft - Electron microscope
Laboratory safety measures
Activity :To observe a laboratory and identify safety rules therein.
(Work in groups)
Your teacher will take you to the laboratory or science room; where you will be conducting physics experiments.
Identify some apparatus you may have seen before.
Identify some situations that may pose danger to learners while in the laboratory.
List at least five safety rules you may think of that should be observed while in the laboratory.
Compare and discuss your findings with other groups in your class.
A laboratory is a room in which science experiments or investigations are conducted. While in the laboratory, you are expected to observe some measures to avoid occurrence of accidents that may harm them or the apparatus.. The list of laboratory safety rules and regulations is quite long and you will be learning more rules and regulations throughout your study in Physics. Generally, the rules and regulations fall under seven main categories as summarised in Table 1.4.
Since it is impossible to eliminate all the risks of an accident, it is your responsibility to minimise them and ensure that you are able to take appropriate action should any occur. In case of an accident, despite taking all the precautions, the most important consideration at all times is human safety. You should act quietly and methodically. Common sense is the best judge.
First aid
Activity: To define first aid and interpret hazard symbols
(Work in groups)
Materials: first aid kit, chart showing hazard symbols
In groups of three, discuss what first aid is and why it is important to have adequate knowledge on first aid.
Open the first aid kit provided to you and identify all the items in it and their uses.
Now, discuss each hazard symbols shown on the chart provided and suggest why it is important to understand them.
The purpose of first aid is to make the victim secure and comfortable. This prevents his/her condition from becoming worse until professional assistance is available. All physics students need to have adequate knowledge of first aid. The physics laboratory should have a fire extinguisher and a first aid kit containing the following items:
• A pair of blunt-ended scissors. • Safety pins.
• Gloves. • Adhesive plaster.
• Mild antiseptic solution. • Forceps.
• An assortment of bandages. • Sterilised cotton wool and gauze.
Hazard symbols and their meanings
Signs and symbols(Fig 1.8) are meant to help us quickly identify the risks we are likely to be exposed to when handling equipments, apparatus and chemicals.
The following are some of the common hazard symbols in a laboratory.
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