Chapter 1: The world of science
1. Introduction to science
1.1 definition of science
Science is knowledge arranged in an orderly manner. This knowledge is acquired through observation and experiment of the nature and behaviour of natural things. Nature refers to everything around us.
1.2 Branches of science and scientist The branches of science (also referred to as scientific fields or scientific disciplines) include:
1) The physical sciences: physics, chemistry and astronomy.
2) The earth sciences: geology, oceanography and metrology. ()
3) The life sciences (biology): botany, genetic and zoology. (medicine)
4) Social sciences: economics, psychology and political science.
5) Mathematical sciences: applied mathematics.
A scientist is a person who studied science and contributed to its development. The table below shows some scientists and their achievements (contributions)
Home work:
1. a) Out of those mentioned above, list three scientists and their contributions. b) What is the name of the vaccine discovered by Prof. Victor Anoma Ngu.
2. General: Basic equipment in a science laboratory
The workshop of a scientist is called a laboratory. Any device that is used by scientist to observe or perform an experiment is called an instrument. The table below shows some basic instruments and their uses in a scientific laboratory:
Careers in science
Science can lead to careers such as:
1) Medicine (nursing, surgery)
2) Engineering (civil engineering, electrical engineering)
3) Telecommunication
4) Transportation (pilots)
5) Agriculture (food science)
Introduction to physics
Definition: Physics is a branch of science that studies matter and energy in all its form. Matter is anything that has weight and occupied space. For example, air and stones. Energy is the ability to do work.
Home work (if possible) 1) The _________is used to measure mass. 2) State the branches of physics that you know.
Braches of physics
Some of the branches or fields of physics include:
Physics can be continued with other subjects to produce new fields of study. For example, biophysics and geophysics.
3. Scientific Methods Part 1
Two of the methods used by scientist include: the observation and measurement.
a) Observation
This is the act of using the human senses to get information about the environment. The senses include: sight, touch, smell, taste and hearing. The term observation may also refer to any data collected during the scientific activity.
b) measurement
This is the act of finding the size, quantity, degree or mass of a given substance. There are two types of measurement, namely: qualitative and quantitative measurements.
Qualitative measurement
This is measurement that does not involve the use of numbers or any measuring devices. For example, Eru is delicious is a qualitative measurement because we cannot measure how delicious something is.
Quantitative measurement
This is a measurement which involves the use of specific measuring instruments. For example, peter is 1.5 m tall is a quantitative measurement.
Home work
State two examples of a qualitative measurement and a quantitative measurement not mentioned above.
Estimate
An estimate is a careful intelligent guess using common senses and all our knowledge. For example, I take around 12 minutes to come to school. An estimate is a guess and is therefore not exact. However, measurement is exact and the same all over the world.
Units of measurement
Definition: a unit of measurement is a standard measure which is used to express other amounts. Example, the meter is the unit for length. A physical quantity is one that can be measured. Example, length, weight, volume, etc…. Other expression like intelligence cannot be measured.
S.I units or international system of units
The confusion that came as a result of every country trying to give and define its own units of measurement made scientists to agree to come out with standard units to be used by everybody, so that scientist can compare and reproduce one another’s observation and hence analyze them without an interpreter of units. The agree system of units is called S.I units or international system of units.
Base physical quantities
A base unit is a unit that is not obtained from any other unit. All the physical quantities can be measured in terms of a small number of base units. The magnitude of a physical quantity is written as the product of a number and unit. There are seven base quantities and their units are called base units. The symbol for a unit named after a scientist is usually denoted with a capital letter. The table below gives the seven base physical quantities, their units and symbols.
Quantity
Additional S.I units
Additional S.I units are obtained by multiplying and/or dividing two or more other base units. The units obtained are then termed derived units. For example, speed=distance/time i.e., unit of speed=unit of distance/unit of time. The derived S.I unit for speed is therefore m/s.
Volume=length x width x height i.e. derived unit for volume=unit of length x unit of width x unit of height. The derived unit for volume is therefore meter x meter x meter.
Homework:
Find the derived unit of the following quantities
- acceleration = speed/time x time
- density=mass/volume
- weight=mass x acceleration
Scales of measurement
A measurement scale is a set of regularly spaced intervals. Examples (on the note)
When using a scale, the zero mark of the scale should coincide with the one of the quantity being measured.
Example
- When taking the reading in a scale, the eye should be placed directly opposite to the graduation, that is, at a perpendicular plane at the point concerned
Example General safetyrules for working in a science laboratory
Importance of studying science
There are several reasons why we study science, some of which are
1) science enables us have good health
2) science enables us to manufacture the thing we need
3) science makes our work easier
4) science provides us shelter
5) science makes communication easy
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