Synopsis Grade 9 Science Term I

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1 Synopsis Grade 9 Science Term I Chapter 1: Matter in Our Surroundings Characteristics of matter particles There are spaces between matter particles Matter particles move continuously movement increases with rising temperature Attract each other decreasing order of force of attraction: solids > liquids > gases Solid phase: Have permanent shape, size and boundary with negligible compressibility Liquid phase: Have a fixed volume with low compressibility but no fixed shape Gaseous state: Have high compressibility with no fixed shape, volume, and boundary Boiling point: temperature at which the vapour pressure becomes equal to the atmospheric pressure. It can also be referred to as the temperature at which a liquid changes to its vapours. Melting point Temperature at which a solid melts into a liquid at normal atmospheric pressure. Effect of change of pressure If pressure is applied, Melting point decreases Boiling point increases Latent heat Heat required for breaking the force of attraction between the particles at transition temperature. Amount of heat required to change 1 kg of material to change its state at normal atmospheric pressure at transition temperature is called the latent heat for that transition. Dry ice Solid carbon dioxide Sublimation Process of changing of a solid to its gaseous form Evaporation Change of liquid into vapours at any temperature below the boiling point. Takes the latent heat from body. Thus, the body cools when evaporation takes place. Factors affecting evaporation Surface area If increases, rate of evaporation increases Temperature If increases, rate of evaporation increases Humidity If increases, rate of evaporation decreases Wind speed If increases, rate of evaporation increases Chapter : Is Matter around Us Pure Mixture Contains more than one pure substance in any ratio/proportion Substance Cannot be separated into its constituent particles by any physical process

2 Solution Homogeneous mixture of two or more substances Alloys Homogeneous mixture of metals Properties of solution: Homogeneous mixture Particles are extremely small, not visible to the naked eye Light path not visible Solute particles cannot be separated by filtration Concentration of solution = Solute amount / Solvent amount Solute mass Mass by mass percentage = 100 Solution mass Solute mass Mass by volume percentage = 100 Solution volume Suspension Heterogeneous mixture of solids and liquids where the solid particles suspend throughout the medium. Example: Mixture of chalk powder and water Properties of suspension o Particles are visible to the naked eye o Light path visible o Particles settle down Colloidal solution- Is a heterogeneous mixture, but appears to be homogeneous. Example: milk Properties of colloidal solution o Heterogeneous mixture o Particle size is small, not visible to the naked eye o Light path can be visible o Particles do not settle down o Substances cannot be separated by filtration Tyndall effect Scattering of light beam by suspended particles in the solution Separation processes Evaporation Used for separating mixture of volatile solvents and non-volatile solutes. Example: Separating salt from its solution Centrifugation Used for separating components based upon the difference in their weights. Example: Separating mixtures of cream from milk Separating funnel Used for separating two or more immiscible liquids. Example: Separating oil and water Sublimation process Used to separate sublimable solids from their mixtures. Example: Separating ammonium chloride from a mixture Chromatography Used to separate those solutes that dissolve in the same solvent. Example: Separating the components of a dye Distillation Used to separate two miscible liquids that boil without decomposition. Example: Separating a mixture of acetone and water Fractional distillation Used to separate a mixture of liquids when the boiling temperature difference is less than 5 K. Example: Separating different components of petroleum

3 Crystallization Used to separate pure solids from a solution by forming crystal. Example: Obtaining pure crystals of copper sulphate from an impure sample Differences between a mixture and a compound Mixture No new compound Elements or compounds mix Properties of constituents remain unchanged A constituent can be separated easily by physical methods Compound New compound Elements react New substance has totally new properties Can be separated by chemical methods or electrolysis Chapter 3: The Fundamental Unit of Life Cell: It is the smallest unit of life capable of performing all living functions. On the basis of cell number, organisms are divided into two types: Unicellular organism: made up of only a single cell, e.g. Amoeba, Paramecium Multicellular organism: made up of many cells, e.g. algae, plants, animals, etc. Structural organization of cell Cell wall: Outermost structure present in plant, fungal and some bacterial cells; absent in animal cells Plasma membrane or cell membrane: Outermost covering of all cells. It separates the contents of the cell from the external environment. Important functions of cell membrane: Regulates the entry and exit of substances in and out from the cell Performs certain physical activities such as diffusion and osmosis o Diffusion: The spontaneous movement of molecules from a region of high concentration to a region of low concentration o Osmosis: The movement of water molecules from a region of high concentration to a region of low concentration, through a selectively permeable membrane Cytoplasm: It is the fluid that fills the cell; It contains all cell organelles Cell organelles Nucleus: It controls all the cellular activities of the cell; acts like the brain of a cell. Important components of nucleus: o Nuclear membrane o Nucleoplasm, containing chromatin o Nucleolus Prokaryotic cell - The nuclear region is poorly defined; membrane-bound organelles are absent. The undefined nuclear region containing only nucleic acid is called nucleoid.

4 Eukaryotic cell Nuclear region is bounded by nuclear membrane; membrane-bound organelles are present Endoplasmic reticulum It helps in the synthesis and packaging of proteins and lipids. SER plays a significant role in detoxifying many poisons and drugs. It is of two types; o SER - Smooth (due to absence of ribosomes) endoplasmic reticulum o RER - Rough (due to presence of ribosomes) endoplasmic reticulum Ribosome: Site of protein synthesis Golgi apparatus: It is known as dictyosomes in plant cells o Helps in the storage, modification, and packaging of products in vesicles o Involved in the formation of lysosomes and peroxisomes Lysosome: It contains digestive enzymes that can destroy any foreign material; also known as the suicidal bag of a cell Mitochondria - It is known as the powerhouses of the cell ; o It is a double membrane bound organelle that have their own DNA; hence they are able to make some of their own proteins o Involved in cellular respiration o Produce energy in the form of ATP (Adenosine triphosphate). Hence, it is also known as energy currency of the cell. Plastids: It is present only in plant cells. These are also double-membraned structures having their own DNA and ribosome. They are of two types; o Chromoplasts (coloured plastids): It include chloroplasts which are important for photosynthesis in plants o Leucoplasts (white or colourless plastids): It help in the storage of carbohydrates (starch), fats, and proteins Vacuole: It is found in both plant and animal cells. It is single and large in plant cells while it is small and numerous in animal cells. Important functions of vacoules: o Provide turgidity and rigidity to plant cells o Store some useful substances like amino acids, sugars, various organic acids etc. o In some organisms specialised vacuole performs the function of expelling waste material and excess of water. Differences between plant and animal cells Animal cell Plant cell

Generally small in size Cell wall is absent Plastids are absent Vacuoles are present in abundance and smaller in size Usually larger than animal cells Cell wall is present Plastids are present

Coined term protoplasm Schleiden and Schwann Presented Cell theory Camillo Golgi First described Golgi apparatus Cell theory All plants and animals are composed of cells The cell is the basic unit of

5 Generally small in size Cell wall is absent Plastids are absent Vacuoles are present in abundance and smaller in size Usually larger than animal cells Cell wall is present Plastids are present Vacuoles are usually single and larger in size Milestones in Cell Biology Biologists Major contributions Robert Hooke Discovered cell Leeuwenhoek Discovered microscope Robert Brown Nucleus Purkinje Coined term protoplasm Schleiden and Schwann Presented Cell theory Camillo Golgi First described Golgi apparatus Cell theory All plants and animals are composed of cells The cell is the basic unit of life. All cells arise from pre-existing cells. Chapter 4: Tissues Tissues: Group of cells that work together to perform a particular function Plant tissues On the basis of the dividing capacity, plant tissues are of two types: Meristematic and permanent tissue. Meristematic tissues: It consists of actively-dividing cells. They are of three types; o Apical meristem: Present at the growing tips of stems and roots. Its function is to increase the length of stems and roots o Intercalary meristem: Present at the base of leaves or internodes. Required for the longitudinal growth of plants o Lateral meristem: Present on the lateral sides of the stems and roots. Its function is to increase the thickness of stems and roots.

Permanent tissues: Formed from meristematic tissues. The cell loses the ability to divide. Divided into two types Simple permanent: Consist of only one type of cells.

6 Permanent tissues: Formed from meristematic tissues. The cell loses the ability to divide. Divided into two types Simple permanent: Consist of only one type of cells. There are three types; o Parenchyma: Composed of unspecialised loosely packed living cells with relatively thin cell walls. o Parenchyma that contains chloroplast and performs photosynthesis is called chlorenchyma. o Parenchyma that contains large air cavities is called aerenchyma. These large air cavities provide buoyancy to aquatic plants. o Collenchyma - Composed of living and elongated cells with cell walls irregularly thickened at the corners; have very little intercellular spaces; provide flexibility and mechanical support to the various parts of the cells. o Sclerenchyma - Composed of long, narrow, and lignin deposited thick-walled cells. This tissue is made up of dead cells and there are no intercellular spaces. For example, husk of coconut. o Protective tissues: Protects the plant from external injuries. The two types of protective tissues are epidermis and cork Complex permanent - Made up of more than one type of cell. These tissues constitute vascular bundles. They are of two types; o Xylem Conducts water and minerals from the roots to the different parts of the plant Composed of four different types of cells; tracheids, vessels, xylem parenchyma, and xylem fibres. Except xylem parenchyma all other xylem elements are nonliving. o Phloem Conducts food material from the leaves to the different parts of the plant Composed of four different types of cells; sieve tubes, companion cells, phloem parenchyma, and phloem fibres. Except for phloem fibres, all other phloem cells are living.

Animal tissues Animal tissues are classified into four types based on the functions they perform: Epithelial, Connective, Muscular and Nervous tissue.

They are of four types; o Squamous epithelium: Single layer of extremely thin and flat cells are called simple squamous epithelium while multi layered cells forms stratified squamous epithelium.

7 Animal tissues Animal tissues are classified into four types based on the functions they perform: Epithelial, Connective, Muscular and Nervous tissue. Epithelial tissues: Tightly packed cells with almost no intercellular spaces. It forms the covering of the external surfaces, internal cavities, and organs of the animal body. They are of four types; o Squamous epithelium: Single layer of extremely thin and flat cells are called simple squamous epithelium while multi layered cells forms stratified squamous epithelium. o Simple squamous epithelium: Lining of the mouth, oesophagus, lung alveoli, etc. Stratified squamous epithelium: Skin o Cuboidal epithelium: Consists of cube-like cells. Found in the lining of kidney tubules and ducts of the salivary glands o Columnar epithelium: Consists of elongated or column-like cells. Found in the inner lining of the intestine and gut o Glandular epithelium: Consists of multicellular glands Connective tissues: Specialised to connect various body organs. Various types of connective tissues are:

8 o Areolar tissue: Found in the skin and muscles, around the blood vessels, nerves, etc. o Adipose tissue: Acts as the storage site of fats; found between the internal organs and below the skin; acts as an insulator for the body o Dense regular connective tissue: Main components are tendons and ligaments. Ligaments: Connective tissues which connects a bone to a bone. It is very elastic Tendons: Connective tissue which connects a bone to a muscle. It has limited flexibility o Skeletal tissue: The main component of skeletal tissues are cartilage and bone o Fluid tissue: Blood is the vascular tissue present in animals. It is composed of plasma, Red blood cells (RBC), White blood cell (WBC) and platelets. Muscular tissues: The main function of muscular tissue is to provide movement to the body. It is of three types o Striated muscles or skeletal muscles or voluntary muscles: Cells are cylindrical, un-branched, and multinucleate. Found in our limbs. o Smooth muscles or involuntary muscles: Cells are long, spindle-shaped, and possess a single nucleus. Found in oesophagus, iris of the eyes, in ureters. o Cardiac muscles or involuntary muscles: Cells are cylindrical, branched, and uninucleate. Found in the heart. Nervous tissues: Highly specialised tissues present in the brain, spinal cord, and nerves. o Neuron: It is the functional unit of nervous tissue. Chapter 5: Motion Uniform motion No change in velocity (No change in speed and direction) Non-uniform motion Change in velocity with time Distance covered Speed = Time taken Displacement Velocity = Time taken Initial velocity + Final velocity v u Total displacement Average velocity = t Total time taken Final velocity Initial velocity vu Acceleration = Time t Distance-time graph

Velocity-time graph Equation of motion 1st equation: v = u + at 1 nd equation: s = ut + at 3rd equation: as = v u The motion of an object moving in a circular path is called circular motion.

9 Velocity-time graph Equation of motion 1st equation: v = u + at 1 nd equation: s = ut + at 3rd equation: as = v u The motion of an object moving in a circular path is called circular motion. Chapter 6: Force and laws of motion Inertia Tendency of a body to resist any attempt to change its state of motion. Mass is the measure of inertia, higher is mass, higher is inertia. Momentum = mass velocity = mv [kg m/s] First law of motion A body at rest remains at rest and a body in uniform motion continue its uniform motion unless an external force is applied. Second law of motion Rate of change of momentum Applied unbalanced force Direction of change in momentum is the same as the direction of unbalanced force o Numerically, F K. ma / F m v u t F ma; for K 1 o Newton = Unit of force, 1 N =1 kg 1 m / s

10 Third law of motion For every action force there is an equal and opposite reaction force. Conservation of momentum For a system, momentum remains constant unless an external force acts on it. maua mbub mava mbvb Chapter 7: Gravitation Kepler s law of planetary motion First law: Orbits of planets are elliptical. Second law: Planet covers equal area in equal time intervals 3 r Third law: T Constant r Distance from sun and T Orbital period Universal law of Gravitation F G Mm r G = Universal gravitational constant = Nm kg 1 Inverse square law: F r Gravitation is a weak force unless large bodies are involved. Force of gravitation due to the Earth is called gravity. Force of gravity decreases with altitude above surface of Earth. Force of gravity decreases with depth below surface of Earth. It also varies on surface of Earth, it decreases from poles to equator. Force of gravitation explains motions of moon and planetary tides The motion of a body in which gravity is the only or dominant force acting upon it is called free fall. Value of acceleration due to gravity during free fall is, g =9.8 m/s, it is independent of mass of the falling object. M m mg G r M g G 9.8 m / s r M = Earth's mass r = Earth's radius Weight of a body = Earth s gravitational pull on the body Weight on moon = 1 weight on Earth 6 Tips to solve numerical For upward motion take g = 9.8ms and final velocity at the highest point as 0.

11 For downward motion take g = 9.8ms and for a freely falling body take initial velocity as 0. Thrust Force acting perpendicular to a surface Pressure = Perpendicular force per unit area Force N / m Pascal Pa Area Buoyant force = Up thrust by a fluid on a body immersed in it [Depends on fluid density] If density of body > density of fluid, then the body will sink in the fluid, and vice versa (Density of cork) < (density of water), so cork floats (Density of iron) > (Density water), so iron sinks Archimedes principle: Upward force experienced by a body immersed in fluid = Weight of the displaced fluid Lactometer is a device to measure purity of milk. Density of a substance Relative density Density of water Chapter 8: Improvement in Food Resources Improvement in crop yields The crops grown in rainy season are known as kharif crops. These are grown from the month of June to October. Soya bean, paddy, maize, cotton, pigeon pea, green gram, and black gram are kharif crops. The crops grown in winter are known as rabi crops. The rabi season is from November to April. Wheat, gram, mustard, linseed, and pea are rabi crops. The variety of the crop can be improved by hybridization and genetic engineering. Hybridization is the crossing between genetically dissimilar plants. It can be intervarietal or interspecific. Genetic engineering is the deliberate insertion or deletion of genes in an organism for obtaining a better organism. The net crop yield can also be increased by adopting better cropping pattern(s) such as inter-cropping, mixed cropping, and crop rotation. Mixed cropping is growing two or more crops simultaneously on the same piece of land Inter cropping is growing two or more crops simultaneously on the same field in a different pattern. The growing of different crops on a piece of land in a pre planned succession is called crop rotation.

12 Factors for high variety improvement Improved quality Biotic and abiotic resistance Change in maturity duration Wider adaptability Desired agronomic characteristics Nutrient management There are 16 nutrient which are essential for plants Carbon, hydrogen and oxygen are called the framework elements The nutrients required in relatively large quantity for growth and development of plants are called macro nutrients. These are nitrogen, phosphorous, potassium, calcium, magnesium, and sulphur The nutrients required in low quantity are called micro nutrients. These are iron, manganese, boron, zinc, copper, molybdenum, and chlorine. Manure o Manure is prepared by the decomposition of animal excreta and plant waste. o Manure is known to have a large quantity of organic materials and little amount of plant nutrients. o Manure helps in enriching the soil with organic matter and nutrients. o Cow dung, animal refuse, domestic wastes, etc., is decomposed to form manure. Fertilizers o Fertilisers are commercially-available plant nutrients. o They can be organic or inorganic in nature. They ensure the healthy growth and development of plants by providing nitrogen, phosphorus, potassium, etc. o Urea, Potash, Ammonium nitrate etc are some examples of fertilisers. Composting o Composting is a process in which farm waste materials such as livestock excreta (e.g., cow dung), vegetable wastes, domestic wastes, and sewage wastes are decomposed in pits to release the organic matter and nutrients. o When composting is done using earthworms to hasten the process of decomposition, it is called vermicomposting. Crop protection Use of pesticides is the most common method of eradicating weeds, pests, and infectious diseases. Pesticides are commercially available as herbicides, fungicides, insecticides, etc. Excessive use of these chemicals can cause health hazards and environmental problems. Animal husbandry Animal husbandry deals with the scientific management of livestock. These include cattle farming, poultry farming, fish culture, and bee culture. Cattle farming is done to obtain milk and draught labour for agricultural purposes. Poultry farming is undertaken to obtain egg production and meat.

13 Fish is a cheap source of animal protein for our food. Therefore, fish culture is an important part of animal husbandry. In composite fish culture both local and imported fish species are used to increase the fish yield. Aquaculture involves the production of aquatic animals that are of high economic value such as prawns, fishes, lobsters, crabs, shrimps, mussels, oysters, etc. The practice of bee keeping is known as apiculture. Bee farms are also known as apiaries. Local varieties of bees used commonly for honey production are Apis cerana, Apis dorsata, A. florae. An Italian bee variety A. mellifera is used for commercial production of honey

Tissues: - A group of cells similar in structure and performing a particular function forms a tissue.

Plant Tissues Class- IX Tissues: - A group of cells similar in structure and performing a particular function forms a tissue. PLANT TISSUES ANIMAL TISSUES 1. Most of the plant tissues are Most of the tissues