General Science Notes: 1st semester | B.Ed Hons | UoB

Unit # 1:     Introduction to Course /Science

What is Science?

The world “Science” probably brings to mind many different pictures: a fat textbook, white lab coats and microscopes, an astronomer peering through a telescope, a naturalist in the rainforest, Einstein’s equation scribbled on a chalkboard, the launch of the space shuttle, bubbling beakers … all of those images reflect some aspect of science, but none of them provides a full picture because science has so many facets:

Ø  Science is exciting. Science is a way of discovering what’s in the universe and how those things work today, how they worked in the past, and how they are likely to work in the future.

Ø  Science is ongoing. Science is continually refining and expanding our knowledge of the universe, and as it does, it leads to new questions for future investigation. Science will never be ‘finished’.

Ø  It’s a systematic knowledge of physical and material world gained through experiments and observation.

Ø  Science is the intellectual and practical activity about the systematic study of the structure and behavior of the physical and natural world through observation and experiment.

Nature of Science and scientific investigation

In general, the nature of science refers to key principles and ideas which provide a description of science as a way of knowing, as well as characteristics of scientific knowledge.

The main ideas regarding the nature of science

The main ideas regarding the nature of science are!

Describing the Nature of Science:

When trying to describing the nature of science, it can be useful to think of science as a culture in just the same way that we thing of the cultural worlds of art and music. We need to understand and talk art or music when we enter these worlds. In the same way, we need to be able to understand and talk science.

Scientific Method Steps:

The scientific method is a systematic means of exploring and explaining the world around us. Experiments are an important part of the scientific method. It’s also called as Scientific Investigation.

Scientific investigation is a quest to find the answer to a question using the scientific method. In turn, the scientific method is a systematic process that involves using measurable observations to formulate, test or modify a hypothesis. Finally, a hypothesis is a proposed explanation for some observed phenomenon, based on experience or research. Scientific investigation is what people like you and me use to develop better models and explanations for the world around them.

Steps for Scientific Investigation

1: Make Observation. 2: Formulate a Hypothesis. 3: Design an Experiment.

4: Test of hypotheses. 5: Accept or Reject hypothesis.

Scientists find things out by carrying out an investigation. Investigations always have a purpose and follow a plan. The aim of investigation is usually stated at the very beginning and may even be the little of the piece of work   

i.                    Which type of material is best for filtering dirty water?

ii.                  To find out which pair of magnets has the strongest attraction for one another

iii.                To find out which type of material keeps the heat in best.

iv.                Do boys or girls have the quickest reactions

Unit # 2:     Populations and Ecosystem

Basic needs of living organism:

There are millions of different living organisms in the world. From plants to animals and human organisms live different existences. Despite the variations, there are five basic needs that are applicable to all living organisms. In order to survive, all living organisms need Air, Water, Food, Sunlight and shelter (proper habitat or protection from the environment). Every organism has its own way of making sure its basic needs are met.

Air: Air is a combination of gases used different by many organisms. Carbon dioxide and oxygen make up two key components of air. Plants use the carbon dioxide in air to create sugars and oxygen.

Water: The amount needed varies, but all living organisms require water. Some organisms live in water, some need salt water and others can only survive with fresh water. Plants take water to grow and create food.

Food: All living organisms need a source of nutrients. Nutrients or food, can include fats, carbohydrates and proteins that are needed to maintain health and growth. Plants take in nutrients from the soil or the surrounding environment. Human and animals eat a variety of foods filled with nutrients. Humans can survive several days without food but eventually the body’s nutrient levels need replenishment.

Sunlight: Sunlight provides multiple uses to all living organisms. First, the sun serves as a heat source that warms the environment. The main necessity for sunlight stems from a plant’s requirement for building food. Plants take in energy from the sun and use it to maintain growth and develop food and oxygen. Animals and humans indirectly need sunlight as a result, as they are heavily dependent on the functions of plants for food and oxygen. Sunlight also provides human with vitamin D, a vitamin that ensures bone strength.

Habitat: While habitats vary greatly from organism to organisms. Every living thing needs an efficient living space in order to survive. A key component of such a habitat is the proper temperature. Some plants can only survive in the dampest of conditions, while other requires a drier home. The habitat must also have sufficient resources for the living organism.

Interdependence of living thing (Symbiosis)

Animals and plant share the biosphere with each other. All animals ultimately depend on the green plants.

Symbiosis: symbiotic relationship is a biological term, which describes the relationship between species that depends on each other for survivor relationship for food, shelter, etc.

Ecosystem

Ecology: In 1866, the German zoologist Ernst Haeckel coined the word ecology from two roots Oikos, meaning ‘a house or living-place’ and logos meaning ‘the study of’. Ecology is the study of interaction or relationship between organisms and their environment. Ecology is also called environmental biology.

Levels of organization in Ecology:

Individual: Single member of a population is known as individual.

Population: A Population is a group of single species that live together in the same area at the same time.

Community: A community consists of all populations of different species living and interacting together within a certain area.

Environment: the surrounding in which an organism lives is called environment. The environment provides all the basic requirements to an organism.

Habitat: Any organism should have a place to live. The place where an organism lives is its habitat.

Biosphere: All the communities of all living things on earth make up the biosphere.

Ecosystem: An ecosystem is a community together with its environment. Ecosystem includes all the interactions among the living organisms of a community and the interactions between the organisms and their physical environment. Interactions between organisms and their environment are ‘give and take’ relationship. An ecosystem regulates the flow of energy, ultimately derived from the sun and the cycling of the essential elements on which the lives of its biotic constituents depend.

Natural area where living organisms and physical environment interact and exchange material to achieve functional stability is known as ecosystem. It may be natural ecosystem or an artificial ecosystem. Natural ecosystems are Pond, Lake, river, ocean, forest desert. Artificial ecosystems are aquarium, dam, and crop land.

The interaction between living and nonliving things leads to balance in the environment.

Components of an ecosystem:

It comprises of the living (biotic) and non-living (abiotic) components. Biotic and abiotic both contribute equally for the proper and regular functioning of the ecosystem.

Abiotic components are:       (1) Light.         (2) Temperature.          (3)Water
(4) Atmosphere and wind.      (5) Fire.           (6) Soil.                       (7)Topography
(8) Gravity.                             (9) Inorganic nutrients.

Biotic components are:         (1) Producers   (2) Consumers             (3) Decomposers

1.      Producers: These are green plants. They are autotrophs. The producers include terrestrial green plants. Aquatic algae and phytoplankton. A part of the carbohydrate produced by the autotrophs is used by them. The rest is used by consumers and decomposers.

2.      Consumers: These are animals. The animals are heterotrophs. Consumers’ may be: i. Primary consumers e.g. herbivores. ii. Secondary consumers e.g.  Carnivores. iii. Omnivores e.g.  man iv. Parasites. E.g. liver fluke, taenia. V. after death by: scavengers e.g. vultures, saprophyte, e.g. mushroom.

3.      Decomposers: Organisms that decompose dead animals and plants are called decomposers. They obtain energy through these processes. (I) Bacteria (II) Fungi). They release all the nutrients tied up in the dead bodies. So that new living things can use them. The rate of decomposition is rapid in summer than in winter.

Population Growth: Survival and extinction:

Scientist has estimated that 1.5 million living organisms prevails on our planet ‘Earth’ in which approximately 5% are single-celled (or Unicellular organisms are bacteria) organisms, 22% are fungi and plants and 70% are animals and by far the largest number of species are the land-dwelling insects.

Extinction: In biology and ecology, extinction is the end of an organism or of a group of organisms,. A species is extinct when the last existing member dies. Extinction therefore becomes a certainty when there are no surviving individuals that can reproduce and create a new generation. A species may become functionally extinct when only a handful of individuals survive, which cannot reproduce due to poor health, age, sparse distribution over a large range, a lack of individuals of both sexes (in sexually reproducing species), or other reasons. The average life-span of a species is 10 million years.

 There are a variety of causes that can contribute directly or indirectly to the extinction of a species or group of species. "Just as each species is unique".

Unit # 3:     Force and Motion

Mechanics:  A branch of physics which deals with the study of the motion of the body is called mechanics.

Rest: when a body doesn’t change its position with respect to its surroundings than its said to be stand of a ‘Rest’.

Motion: When a body changes its position with respect of its surroundings than it is set to be in the state of motion.

Types of Motion:

i.                    Translatory Motion: The type of motion in which every particular part of body has exactly the same notion is called Translatory motion.

-          Liner Motion: the motion in straight line (gravity)

-          Circular Motion: moving in circular/ circle position.

-          Random Motion: The body moves in irregular means.

ii.                  Rotatory Motion: When the parts of body moves to a fix point.

iii.                Vibratory Motion: To & Fro (the spring)- moving/swing up & down, side to side.

Distance: The product of average speed and time is called Distance, its noted by “S”

-          Scalar:                        No Direction

-          Victor:                        Direction

Displacement: The shorter distance between two points is called displacement.

Speed: The distance covered in a unit time is called Speed.

Average speed: The ratio of total distance covered by body to the total time is called average speed.

Uniform Speed: if a body covers equal distance in equal interval of time, however small the intervals may be the speed of the body is set to be unformed

Variable: if a body covers unequal distance.

Velocity: The distance covered in unit time in particular direction is called Velocity. –OR- the time rate of displacement of a body called Velocity.

Acceleration: The rate of change of velocity is called Acceleration.

Positive Acceleration: if the velocity of moving body is increasing its acceleration will be positive.

Negative Acceleration: if the velocity of moving decreasing its acceleration will be negative.

Average Acceleration: it’s the ratio of total change in velocity of the total time.

Newton’s Law of Motion:

Newton’s First law of Motion:

This law states that in the absence of an unbalanced force an object continues its state of rest or uniform motion.

Newton’s first law consists of two parts.

1^st Part:  First part of describes that a body at rest will remain at rest, until an external force is applied to move it.

Example: A Book lying on the table does not change its position by itself.

2^nd Part: The second part describes that a body once set in motion will always remain moving a force is applied to stop is.

Example: Suppose a car is moving with uniform velocity. According to Newton’s first law of motion, it should be moving with same uniform velocity but practically we see that when engine of the car is turned of it stops gradually. The car could not maintain its uniform velocity, if resistive force of air and friction between tyres and road, do not exist then the car continues its motion.

Newton’s 2^nd Law of Motion:

When a force act upon a body, acceleration is produced in the direction of force and the magnitude of acceleration is directly proportional to the force and inversely proportional to the mass of the body.

Explanation: Suppose a force is applied on the body which produces motion in the body. But if we increase the force on the body it moves faster which means more acceleration is produced.

Contrary to it, if equal forces are applied on two bodies of different masses then the acceleration produced in the body of smaller mass will be more than the body of larger mass. This is acceleration will be produced in the direction of force.

Newton’s Third Law of Motion:

Every action is a reaction. Action and reaction are equal in magnitude but opposite in direction.

Examples:

While walking on the ground, we push the ground in backward direction with our feet it is our action on the ground. As a result the ground pushes us with the same force in the opposite direction. This is the reaction of the ground upon us due to which we move forward while walking.

Differentiate between MASS and WEIGHT?

MASS: is a quantity of a matter, it is denoted by “m”, It is a scalar quantity. It remains constant every-where. It value can never be zero. It is measured by an ordinary balanced.

WEIGHT: weight is the force of attraction with which the earth attracts a body towards its Centre. It is denoted by “w”. It is a vector quantity. It is not the same every-where. It may become zero. It is measured by a spring balance.

Force and Motion

Mechanics:  A branch of physics which deals with the study of the motion of the body is called mechanics.

Rest: when a body doesn’t change its position with respect to its surroundings than its said to be stand of a ‘Rest’.

Force: Force is that agency which change or tends to change to state of rest or motion of a body.

Motion: When a body changes its position with respect of its surroundings than it is set to be in the state of motion.

Types of Motion:

iv.                Translatory Motion: The type of motion in which every particular part of body has exactly the same notion is called Translatory motion.

-          Liner Motion: the motion in straight line (gravity) example: Motion of freely falling bodies.

-          Circular Motion: moving in circular/ circle position.

-          Random Motion: The body moves in irregular means. For example motion of a gas molecules.

v.                  Rotatory Motion: When the parts of body moves to a fix point. Example: ceiling fan

vi.                Vibratory Motion: To & Fro (the spring)- moving/swing up & down, side to side. Motion of swing.

Distance: The product of average speed and time is called Distance, its noted by “S”

-          Scalar:                        No Direction

-          Victor:                        Direction

Displacement: The shorter distance between two points is called displacement.

Speed: The distance covered in a unit time is called Speed.

Average speed: The ratio of total distance covered by body to the total time is called average speed.

Uniform Speed: if a body covers equal distance in equal interval of time, however small the intervals may be the speed of the body is set to be unformed

Variable Speer: if a body covers unequal distance in equal interval of time, however small the intervals may be the speed of the body is said to be variable.

Velocity: The distance covered in unit time in particular direction is called Velocity. –OR- the time rate of displacement of a body called Velocity.

Uniform Velocity: If the magnitude of velocity (speed) and direction of moving body does not change with time then its velocity is said to be uniform.

Variable Velocity: If the magnitude of velocity (speed) or direction or both change, then the velocity of such a body is said to be variable.

Relative Velocity: When two bodies are in motion then the velocity of one body relative the other is called relative the other is called relative velocity.

Acceleration: The rate of change of velocity is called Acceleration.

Positive Acceleration: if the velocity of moving body is increasing its acceleration will be positive.

Negative Acceleration: if the velocity of moving decreasing its acceleration will be negative.

Average Acceleration: it’s the ratio of total change in velocity of the total time.

Uniform Acceleration: If velocity of a body changes equally in equal intervals of time, its acceleration is said to be uniform.

Variable Acceleration: If the velocity of body does not change equally in equal intervals of time, its acceleration is said to be variable.

Newton’s Law of Motion:

Newton’s First law of Motion:

This law states that in the absence of an unbalanced force an object continues its state of rest or uniform motion.

Newton’s first law consists of two parts.

1^st Part:  First part of describes that a body at rest will remain at rest, until an external force is applied to move it.

Example: A Book lying on the table does not change its position by itself.

2^nd Part: The second part describes that a body once set in motion will always remain moving a force is applied to stop is.

Example: Suppose a car is moving with uniform velocity. According to Newton’s first law of motion, it should be moving with same uniform velocity but practically we see that when engine of the car is turned of it stops gradually. The car could not maintain its uniform velocity, if resistive force of air and friction between tyres and road, do not exist then the car continues its motion.

Newton’s 2^nd Law of Motion:

When a force act upon a body, acceleration is produced in the direction of force and the magnitude of acceleration is directly proportional to the force and inversely proportional to the mass of the body.

Explanation: Suppose a force is applied on the body which produces motion in the body. But if we increase the force on the body it moves faster which means more acceleration is produced.

Contrary to it, if equal forces are applied on two bodies of different masses then the acceleration produced in the body of smaller mass will be more than the body of larger mass. This is acceleration will be produced in the direction of force.

Newton’s Third Law of Motion:

Every action is a reaction. Action and reaction are equal in magnitude but opposite in direction.

Examples:

While walking on the ground, we push the ground in backward direction with our feet it is our action on the ground. As a result the ground pushes us with the same force in the opposite direction. This is the reaction of the ground upon us due to which we move forward while walking.

Types of Motion:

1.      Translator motion:

Differentiate between MASS and WEIGHT?

MASS: is a quantity of a matter, it is denoted by “m”, It is a scalar quantity. It remains constant every-where. It value can never be zero. It is measured by an ordinary balanced.

WEIGHT: weight is the force of attraction with which the earth attracts a body towards its Centre. It is denoted by “w”. It is a vector quantity. It is not the same every-where. It may become zero. It is measured by a spring balance.

FIRST EQUATION OF MOTION Vf = Vi + at
Consider a body initial moving with velocity "Vi". After certain interval of time "t", its velocity becomes "Vf". Now
Change in velocity = Vf - Vi OR DV =Vf – Vi
	Due to change in velocity, an acceleration "a" is produced in the body. Acceleration is given by
	a = DV/t
	Putting the value of "DV"
	a = (Vf – Vi)/t at = Vf – Vi at + Vi =VfOR
SECOND EQUATION OF MOTION OR S = Vit + 1/2at2
Consider a car moving on a straight road with an initial velocity equal to ‘Vi’. After an interval of time ‘t’ its velocity becomes ‘Vf’. Now first we will determine the average velocity of body.
Average velocity = (Initial velocity + final velocity)/2 OR Vav = (Vi + Vf)/2
but Vf = Vi + at
Putting the value of Vf
Vav = (Vi + Vi + at)/2 Vav = (2Vi + at)/2   Vav = 2Vi/2 + at/2  Vav = Vi + at/2                           Vav = Vi + 1/2at.......................................(i)
we know that
S = Vav x t
Putting the value of ‘Vav’
S = [Vi + 1/2at] t

Properties and Matter:

Definition of Chemistry: Chemistry is a branch of physical science that studies the composition of structure properties and change of matter.

Physical Property: Appearance can change into other shape and able to return in 1^st shape. 
It can be measured without changing the chemical identity. The freezing point of a substance is physical property, when water freezes its still H2o.

Chemical Property: Can’t change/ return into original shape.
It deals with how one chemical reacts with another we know that wood is flammable because it becomes heat, ash and carbon dioxide when heated in the presence of oxygen.

Boiling point: 100° when external pressure of liquid is equal to internal pressure of liquid.

Melting Point: When a solid thing start melting or change into other shape.

Mater: Matter is defined as anything which has mass and occupies space is called matter. There are three states of matter: Solid, Liquid, and Gas. Matter is made up of atoms, molecules or ions.

Mass: Mass is a measure of an object’s intertie. It’s property of a physical body.

Volume: is a measure of the amount of space occupied by an object.

Element: an element is a substance consisting of atoms which all have the same numbers of protons.

Atom: The smallest particle of an element or compound which may or may not exist independently is called atom. It is representative by a symbol.

Molecule: The smallest particle of an element or compound which can exist independently is called molecule. It is represented by molecular formula.

Molecules may be simple or complex. Here are examples of common molecules:

H2O (water) - N2 (nitrogen) - O3 (ozone) - C6H12O6 (glucose, a type of sugar)

A single oxygen, O, is not a molecule. When oxygen bonds to itself (e.g., O2, O3) or to another element (e.g., carbon dioxide or CO2), molecules are formed.

Types of Molecule: Most atoms join up with other atoms through chemical BONDS to form larger particles called molecules. They can join up with atoms of the same element or with atoms of different elements. Substances whose molecules contain different types of atom are called compounds.

Heteronuclear diatomic: Heteronuclear diatomic molecules are composed of two atoms of two different elements.

Homonuclear molecules: Homonuclear molecules, or homonuclear species, are molecules composed of only one type of element. Homonuclear diatomic molecules include hydrogen (H2), oxygen (O2), nitrogen (N2) and all of the halogens. Ozone (O3) is a common triatomic homonuclear molecule.

Compound: A compound is a substance formed when two or more chemical elements are chemically bonded together. 

A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions.

Mixture: Mixture is a material system made up of two or more different substances which are mixed but are not combined chemically.
A mixture refers to the physical combination of two or more substances on which the identities are retained and are mixed in the form of solution, suspension and colloids.

The Kinds of Mixture:

Homogeneous: A homogeneous mixture is a type of mixture in which the composition is uniform and every part of the solution has the same properties. Air is a homogeneous mixture of the gaseous substances nitrogen, oxygen and smaller amounts of other substances.

Heterogeneous: A heterogeneous mixture is a mixture of two or more chemical substances (elements or compounds) Examples are: mixture of sand and water –OR- sand and iron filings, water and oil.

The Particle Theory:

The kinetic theory of matter (particle theory) says that all matter consists of many, very small particles which are constantly moving on in a continual state of motion. The degree to which the particles move is determined by the amount of energy they have and their relationship to other particles.

The particle theory of matter explain the following scientific phenomena:

1.      Pure substance are homogeneous (one phase – One unique kind of particle)

2.      Physical changes – Melting, evaporation, Sublimation, Dissolving…

3.      Characteristic physical properties – Density, Viscosity, Electrical & thermal conductivity.

Properties of Matter:

Properties: Information about a substance that describe it and that helps us identify it. Characteristic physical properties – are physical properties that can be used to identify a substance because they never change. Example: They density of water is always 1.00 g/mL at too temperature.

_______________
Periodic Table:

When we look at the history of the chemical sciences, we see that the more significant achievements are in the development of the periodic table. Periodic table of the elements can help us to systematize the properties of the elements.

Periodic table gives us a basic framework to understand the chemistry of the elements. It also gives us information of periodic properties of compounds.

The following scientists have done major contributions towards the developments of model of periodic table:

(i): Al-Razi.      (ii): Dobereiner.           (iii): Newland. (iv): Mendeleev.          (v) Moseley

- in the modern periodic table all the elements are strictly arranged in the increasing order of their atomic numbers. 

Chemical Symbols
Name	Symbol	Name	Symbol	Name	Symbol
Carbon	C	Fluorine	F	Hydrogen	H
Iodine	I	Nitrogen	N	Oxygen	O
Phosphorus	P	Potassium	K	Sulfur	S
Uranium	U	Aluminum	Al	Bromine	Br
Calcium	Ca	Chromium	Cr	Gold	Au
Helium	He	Iron	Fe	Lead	Pb
Magnesium	Mg