PSEB Notes

This PSEB 9th Class Welcome Life Notes Chapter 6 Managing Emotions will help you in revision during exams.

PSEB 9th Class Welcome Life Notes Chapter 6 Managing Emotions

→ Everyone has a lot of emotions and everyone keeps showing them.

→ But it is important for us to control these emotions or it could be more harmful than good.

→ We can be very intelligent and successful if we are able to understand our emotions because a balance of emotions can get us on the road to success.

→ Balancing emotions means that we need to know exactly how to express a particular emotion.

→ If we manage to strike this balance, we can certainly succeed in life.

→ Emotions are like ocean waves that can jump at any moment.

→ If ocean waves occur on a large scale, Tsunami can occur.

→ In the same way, it can be harmful if the emotions occur on a large scale.

→ That’s why emotions should be kept in control or they can have a wrong impact on our social and mental health and on family relations.

→ If we want to express ourselves, it is important that we get in the habit of writing a diary on a daily basis.

→ Diary becomes a companion of happiness and keeps our secrets like a trusted friend.

→ We can lighten our minds by writing in a diary.

→ The person’s thinking and attitude should be positive.

→ We should always have forward-thinking.

→ We have to be humble with others or we will be at a great loss.

→ We need to maintain a balance of emotions and express them to a limited extent.

→ We have some negative and positive emotions and there is a need for their proper coordination.

→ We need to throw out the negative emotions and have more positive emotions.

This PSEB 9th Class Welcome Life Notes Chapter 5 Creative Thinking will help you in revision during exams.

PSEB 9th Class Welcome Life Notes Chapter 5 Creative Thinking

→ Creative thinking is the basis of human life.

→ When we think of innovation in life, it is called creative thinking.

→ When we look at something in a new way or think about it in a new way, it is because of our creative thinking.

→ Nature also keeps on creating something new.

→ Just like new flowers grow on a tree, so much new is being created every moment.

→ We can also think and create something new with our creative thinking.

→ We can start a new creation from our room.

→ We can point the walls nicely.

→ We can make the covers of our books and copies better.

→ We all live in the world and while living in the world, we face many kinds of problems.

→ Only then can we try to find a solution to that problem.

→ It is our thinking that helps us to find the best solution to the problems we face.

→ For example, you might have remembered the story of a thirsty crow who found the solution to the problem when he found less water in a Jug.

→ In the same way, we have an example of Dasrath Manjhi who lived in Bihar.

→ He worked between the hills.

→ One day his wife came to give him food.

→ She fell down from the hill and died.

→ The Hospital was. 55 km away.

→ She could have survived if she could have reached early.

→ Manjhi worked very hard alone for 22 years, cut the mountain, and made a 360 feet long and 30 feet wide road.

→ Initially, people made fun of him but later on, he was called. “The mountain man.”

This PSEB 9th Class Welcome Life Notes Chapter 4 Empathy will help you in revision during exams.

PSEB 9th Class Welcome Life Notes Chapter 4 Empathy

→ Emotions are an important part of our life.

→ We use many of the emotions in our daily life such as anger, love, fear, hardness, pain, etc.

→ As emotions are an important part of our life, it is necessary to learn that which emotion could be used at what time.

→ For example, laughter is good for health but laughing at the time of death of anyone becomes a wrong expression.

→ It is a must for us to identify the emotions, accept them and keep them under control.

→ Our society is based on social values and such a society is known as a civilized society.

→ Society runs smoothly due to such values as norms, honesty, respect, sense of responsibility, etc.

→ Few other emotions are also important such as cooperation, maintaining balance with others, etc.

→ The whole of the world is full of diversity and every creature knows that he is different from others.

→ While living in society, we come to know about many languages, customs, cultures, etc.

→ India is full of such diversity.

→ That’s why unity in diversity is quite visible in India.

→ Many communities and groups live in society.

→ We must live in peace and harmony with the people of different languages, religions, etc. We must respect such diversity.

→ Helping others is quite good but while helping, keep in mind that the person is needy or not. If not then the help will be in vain.

This PSEB 9th Class Welcome Life Notes Chapter 3 Interpersonal Relationships will help you in revision during exams.

PSEB 9th Class Welcome Life Notes Chapter 3 Interpersonal Relationships

→ This chapter deals with the issue of interpersonal relationships and how we have to deal with mutual relations.

→ Family is just like a tree. Every member of the family is like a branch of a tree.

→ Each member of the family has its own importance.

→ If a member dies, the person is greatly missed.

→ The family tree continues to grow.

→ That’s why it is important for us to continue to water this family tree with respect and love.

→ This will make the tree grow and flourish.

→ A small story is also given in the chapter ‘Live and Let Others Live’.

→ This story has many characters such as Komal Preet Kaur, Pooja Sharma, Anmol, and Manjit Singh.

→ This story starts with the conversation between Pooja and Komal and they move to tuitions.

→ After this, Manjot and Simran misbehave with Pooja and Komal and try to harass them.

→ Then Komal and Pooja discuss that how to get rid of this problem.

→ They do not want to discuss the matter with their parents or teachers as they could take out their own fault in it.

→ Then they think of Anmol who is a common friend of all.

→ Komal and Pooja share the whole of the incident with Anmol who further says that he will discuss the matter with Manjot and Simran.

→ Anmol meets both of the boys and tells them that in adolescent age, there is a character-building process.

→ That’s why they must keep control of themselves.

→ Anmol tells them that teasing girls is called Eve Teasing and teasing boys is known as Adam Teasing.

→ It is a criminal offense and an individual can be punished for such actions.

→ After listening to this from Anmol and both the girls, both Manjot and Simranjit understand the things and apologize for their actions. They promise them not to repeat the same mistake.

→ Anmol says that we must follow the concept of Live and Let Live.

→ In this way, they will become good friends.

This PSEB 9th Class Welcome Life Notes Chapter 2 Critical Thinking will help you in revision during exams.

PSEB 9th Class Welcome Life Notes Chapter 2 Critical Thinking

→ We live in society and while living in society, we have certain dreams.

→ To fulfill our dreams, occasionally we do daydreaming or talk in vague.

→ We have to fight and win the war to fulfill our dreams.

→ We have to work hard to fulfill our dreams which give us determination.

→ Only with a concentration of mind, we can make our dreams come true.

→ While living in the world, we compare many things with others. Sometimes, the comparison is positive which is good.

→ But if the comparison becomes negative then the person becomes jealous and starts walking on the path of despair.

→ If we are not satisfied with our situation and do not adopt positive thinking then we cannot have all-around development.

→ So, instead of trying to be negative, we must learn good things from others and should talk in a constructive way.

→ No two individuals are the same in this world.

→ They must have some differences between them.

→ We must learn from such differences to move forward, Modern media has made the whole world much smaller.

→ We can see and talk to a person sitting thousands of kilometers away.

→ But we must use the media wisely and not let them dominate us.

→ In the age of modernization, one should use the means of entertainment for one’s own entertainment but we must not forget the books which cannot be replaced in any case.

→ We must use social media wisely and in a constructive way.

→ We must not let social media dominate us and only use it to increase our knowledge.

This PSEB 9th Class Welcome Life Notes Chapter 1 Self Awareness and Self Discipline will help you in revision during exams.

PSEB 9th Class Welcome Life Notes Chapter 1 Self Awareness and Self Discipline

→ Man is a social animal and from the ages, he is struggling to find his identity and true existence.

→ That’s why he needs to coordinate with others to live in society, there is much hidden in a person’s mind and personality.

→ The real purpose of self-consciousness is to identify oneself correctly.

→ Every person has some of the other quality and often he does not even know it.

→ You need to find and use that particular quality.

→ Everyone needs to build their identity while living in society and he can do this by finding qualities within himself.

→ One should always analyze oneself and needs to find the answers to all the questions which revolve around his identity. We must always improve ourselves.

→ If a person has qualities then he also has weaknesses.

→ One can only make one’s true identity if one realizes one’s shortcomings and does not allow them to dominate one another.

→ In this way, he should always be willing to cooperate with others.

→ There is a time limit for everyone. He must complete his tasks on time and live a disciplined life.

→ We must know the importance of time.

→ Once the time is gone, it doesn’t come back.

→ So, we must not waste our time on idle work and spend it on fruitful work, That’s why we must know how to manage the time, must make the time table.

→ Everyone does his work only while living in society.

→ In this way, everyone’s duty is to fulfill their responsibilities properly.

→ If everyone does not fulfill their responsibilities properly, society will not move properly.

→ We have many obligations to other people and if we fulfill these obligations properly, it helps in our physical, emotional, and social development.

This PSEB 9th Class Science Notes Chapter 15 Improvement in Food Resources will help you in revision during exams.

PSEB 9th Class Science Notes Chapter 15 Improvement in Food Resources

→ Food is the basic requirement of all organisms for their survival.

→ Food supplies nutrients like proteins, carbohydrates, fats, vitamins, and minerals to our bodies.

→ Human beings are dependent on animals and plants for food.

→ Human beings obtain most of this food from plants and animals.

→ Therefore, it is necessary to increase production efficiency for both crops and animals (Livestock, Poultry, Fishes, Honeybees).

→ Plants provide food like cereals, pulses, oilseeds, fruits, and vegetables.

→ Animals provide milk and milk products, meat, eggs, honey, etc.

→ Agriculture is the largest industry in India, engaging about 70 percent of our population.

→ The sustainability of agriculture can be achieved by adopting various techniques such as mixed cropping, crop rotation, and crop improvement.

→ Sustainable agriculture is the successful management of resources for agriculture to satisfy the changing human needs while maintaining or enhancing the quality of the environment and conserving natural resources.

→ Mixed cropping is the practice of cultivating more than one crop, that is, growing two or more crops, simultaneously in the same field.

→ In the agroforestry system, crops are grown alongwith trees.

→ The practice of growing different types of crops alternately in the same field is called crop rotation.

→ 16 nutrients are essentially required, four are required in large quantities and are known as macronutrients whereas nine nutrients required in small quantities are known as micronutrients.

→ Manures and fertilizers are the main sources of nutrients supplied to plants.

→ Manures increase soil fertility.

→ Fertilizers are commercially manufactured materials from chemicals.

→ Fertilizers increase the yield of crops.

→ Insect pests and diseases can cause 50-70 percent damage to crops.

→ Weeds are unwanted plants that grow in fields.

→ Mineral or chemical fertilizers contain inorganic chemical substances like nitrates, phosphates, potassium, etc.

→ Chemical fertilizers are required in smaller bulk.

→ Chemical fertilizers are expensive.

→ Compost manure mainly consists of rotten vegetables and animal refuse.

→ Biofertilizers are organisms that bring about soil nutrient enrichment.

→ Soil water acts as a medium for the conveyance of salts needed in plant nutrition.

→ Breakthrough in cereal production due to the use of high-yielding varieties, higher dose of fertilisers, and irrigation is known as the green revolution.

→ Varietal improvement is required for higher yield, good quality, and changing situations.

→ Storage losses in agricultural production may be quite high due to the following biotic and abiotic factors:

• Insects
• Rodents
• Fungi
• Mites
• Bacteria

→ Abiotic factors include excess moisture and inappropriate temperature.

→ These factors cause degradation in quality, loss in weight, poor germinability, and discoloration of produce.

→ Proper drying and fumigation using chemicals that can kill pests are some of the preventive measures.

→ Animal husbandry is the science of rearing, caring, breeding, and utilization of animals.

→ The main aim of animal husbandry is to provide proper food, water, and good shelter to animals.

→ It also involves protecting them from diseases, and their breeding for its best economic use.

→ Cows, buffaloes, fowl, fish, goats, and sheep are useful animals. They provide us food i.e., milk, egg, wool, and meat (fowl and goat).

→ Milk contains all nutrients such as carbohydrates, protein, fats, vitamins, and minerals.

→ Breeds of cattle are divided into three categories: Milch breeds (provide milk e.g. Gir, Sahiwal, Red Sindhi, etc.); draught breeds (used as work animals e.g. Malvi, Hallikar, etc.) and dual-purpose breeds (e.g. Haryana, Deoni, Tharparkar, etc.)

→ Important indigenous breeds of buffaloes are Red Sindhi, Sahiwal, Murrah, Mehsana, Surti, Nili Ravi, etc.

→ Important exotic breeds of milch cows are Holstein and Friesian (Holland), Jersey (USA), Brown-Swiss (Switzerland), etc.

→ Exotic breeds of cows have a longer lactation period and more average annual milk production than those of indigenous breeds.

→ High milk-yielding cross-breeds of cows are Karan-Swiss, Karan-Fries, Frieswal, etc. These have been developed at NDRI Kamal. Kamal-Swiss is a crossbreed of Sahiwal and Brown Swiss.

→ Two main components of cattle feed are roughage (fiber-rich but with low nutrients) and concentrate (rich in proteins, palatable, and easily digestible).

→ A good shelter improves the health and yield of animals.

→ Animal Feed: It means food provided to the animal, which are of two types:

• Roughage: It is a coarse and fibrous food with low nutrition, such as green fodder, silage, hay, and legumes.
• Concentrates: These are the substances that are rich in one or more nutrients. Cotton seeds, oil seeds, oil cakes, and some cereals like gram and bajra are some typical concentrates.

→ Breeding of cattle is done in two ways natural and artificial.

→ Egg production in chicken: Egg production is the most economic trait.

→ A layer hen starts laying eggs at the age of 20 weeks. The egg production period in a commercial layer is 500 days.

→ For increasing the egg production for the development of new variety with respect to quantity and quality of eggs, the following points are to be considered:

• Egg number
• Sexual maturity
• Egg weight
• Bodyweight
• Feed efficiency
• Egg size
• Egg shape
• Shell colour
• Shell quality
• The internal quality of egg

→ Poultry farming provides meat, eggs, and manure (poultry waste).

→ Poultry farming is raising domestic fowls, ducks, geese, turkeys, pigeons etc. Poultry production includes egg production and broiler production for poultry meat.

→ To enhance poultry production, crossbreeding is done between Indian and exotic breeds for variety improvement.

→ Fishes may be obtained from seas i.e. marine resources and rivers, lakes i.e. inland resources.

→ To increase production of a choice variety of fishes can be cultured in marine and inland ecosystems.

→ Fishes are caught by fishing nets and gears operated from fishing vessels having modern devices such as echo-sounders and navigational gadgets.

→ In freshwater, the induced breeding technique is very useful in obtaining quality fish seeds in large quantities.

→ A composite fish culture system is used commonly to produce table fish.

→ Fisheries are composed of finfishes (true fishes) and shellfish include prawns, mollusks, etc.

→ Beekeeping is done to get honey and wax.

→ The honey flow period is the total time period in which bees collect nectar and pollen.

→ Macronutrients: The mineral nutrients needed by plants in large amounts are called macronutrients e.g. Nitrogen, Phosphorus, Calcium.

→ Micronutrients: The mineral elements needed by plants in very small amounts e.g. Boron, Zinc, Copper.

→ Farm Yard Manure (FYM): Livestock farm waste i.e. cattle excreta (cow dung and urine) is stored in a pit for decomposition. After 1-2 months this is used as FYM in farming practices.

→ Compost: The process in which waste material like vegetable waste, animals refuse, domestic waste, sewage waste, straw, eradicated weeds, etc. is decomposed in pits and is known as composting. The compost is rich in organic matter and nutrients.

→ Green Manure: In the cultivation field prior to the sowing of the seeds, some crops like sun hemp, guar, etc. are grown. After some time these plants are mulched by ploughing. These green plants thus turn into green manures which helps in enriching the soil by N and P.

→ Insecticides: Chemicals that kill insects.

→ Manures: Manures are the organic substances obtained from the decomposition of vegetable and animal wastes by the action of microorganisms.

→ Weeds: The small-sized unwanted plants which grow along with a cultivated crop in a field are called weeds.

→ Weedicides: Chemicals that destroy weeds are called weedicides.

→ Humus: Manures provide humus to the soil. Humus improves the physical and chemical texture of the soil.

→ Mixed cropping is the practice of cultivating more than one crop, that is, growing two or more crops, simultaneously in the same field.

→ Crop rotation: The practice of growing different types of crops alternately in the same field is called crop rotation.

→ Animal husbandry: Science of rearing, feeding, caring, and breeding of animals.

→ Roughage: It is a coarse and fibrous food with low nutrition, such as green fodder, silage, hay, and legumes.

→ Concentrates: These are the substances that are rich in one or more nutrients. Cotton seeds, oil seeds, oil cakes, and some cereals like gram and bajra are some typical concentrates.

→ Poultry: Rearing of birds to increase the yield of meat and eggs.

→ Livestock: Domesticated animals like cattle, sheep, goats, camels, horses, pigs, etc.

→ Pisciculture: Pisciculture is the rearing and breeding of fish by a man in ponds, tanks, and artificial reservoirs.

→ Artificial insemination: Introducing the semen of a fertile male into the vagina of a fertile female.

This PSEB 9th Class Science Notes Chapter 14 Natural Resources will help you in revision during exams.

PSEB 9th Class Science Notes Chapter 14 Natural Resources

→ Earth is the only planet on which life exists.

→ Life on earth depends upon ambient temperature, water, and food.

→ The resources on earth are equally important.

→ The most important requirement is solar energy.

→ The environment is the surroundings of an organism and influences its life.
or
The environment is the sum total of all the components both from living and non-living ones.

→ The living or biotic components include plants, animals, and microorganisms whereas non-living or abiotic or physical components consists of air, water, soil, light, and temperature.

→ The habitat of plants and animals greatly varies.

→ Natural resources. It is the stock of nature such as air, water, soil, coal, minerals, animals, and plants that are useful to mankind in many ways.

→ Life on earth depends upon resources like soil, water, air, and energy from the sun. Inexhaustible resources are present in plenty and cannot be exhausted by man’s consumption.

→ The stock of exhaustible natural resources in nature is limited and will finish sooner or later.

→ Air is an important form of inexhaustible natural resource which is essential for our survival.

→ Composition of Air:

• Nitrogen (N₂) – 78%
• Oxygen (O₂) – 21%
• Carbon dioxide (CO₂) – 0.03%
• Argon – 0.93%
• Helium, Neon, Ozone, Ammonia – 0.04%

→ Helium, Argon, and Neon are noble gases.

→ Lithosphere: It is the outer crust of our planet, the Earth.

→ Hydrosphere: It is the portion of the earth’s surface covered with water which is about 75 percent—comprising of seas, oceans, rivers, streams, lakes, ponds, etc.

→ Atmosphere: It is the multilayered gaseous envelope of air that covers the whole of our planet Earth like a blanket.

→ Atmosphere plays important role in the control of climate, movement of air (winds), and rain.

→ Biosphere: It is the life-supporting zone of the Earth where the atmosphere, the hydrosphere, and the lithosphere interact and make life possible.

→ It occupies the highest position or level in the hierarchy of organisation on the earth.

→ Water is an important medium for all the life processes and acts as a universal solvent and is termed ‘wonder liquid’.

→ Water covers 75% of the earth’s surface.

→ The oceans, rivers, streams, lakes, ponds, pools, polar ice caps, water vapours constitute the hydrosphere.

→ Soil is another main natural resource essential for our survival and development.

→ Soil forms the upper surface of the land and supports plant growth.

→ Soil is an important resource that decides the diversity of life in an area.

→ The outermost layer of Earth is called the crust and the minerals found in this layer supply a variety of nutrients to life forms.

→ Causes of Soil Erosion:

• Wind causes soil erosion by carrying away the top loose soil particles.
• Rain causes soil erosion on unprotected topsoil by washing it down.
• Improper farming or tilling and leaving the field fallow for a long time causes soil erosion.
• Frequent flooding of rivers causes soil erosion by removing the fertile topsoil of the fields near the river banks.
• Deforestation also leads to soil erosion.

→ The underground reservoir of the earth of metals and minerals is limited.

→ Renewable sources of energy are regenerated naturally within a short span of time e.g. plants, animals, sunlight, etc.

→ Non-renewable sources of energy take millions of years to form like coal, lignite, petroleum, and natural gas.

→ The substances like water, oxygen, carbon, and nitrogen move from one stage to another say from biotic to abiotic and again to biotic components in a cyclic manner.

→ Air Pollution: It is an undesirable change in the physical, chemical, or biological characteristics of air. It is caused due to an increase in the content of harmful substances (air pollutants) in the air such as oxides of nitrogen and sulphur, etc.

→ The major sources of air pollution are the burning of fossil fuels like coal and petroleum, automobiles, thermal power plants, and industries.

→ Pollution of air, water, and soil affects the quality of life and harms biodiversity.

→ Water Pollution is the contamination of the water of rivers and lakes with unwanted and harmful substances.

→ Water is said to be polluted when there is any physical, biological, or chemical change in its quality that adversely affects living organisms and makes it unfit for use.

→ The balance in the environment including the flow of energy and matters is also supported by various living beings by acting as producers and consumers.

→ Forests provide timber for building and furniture along with raw materials for the paper industry.

→ Ozone layer: Ozone is a triatomic gas with a molecular formula O3 which is present in the upper reaches of the atmosphere (in the stratosphere region).

→ The ozone layer prevents the harmful radiations of the sun from reaching the surface of the earth, where they may damage many forms of life.

→ Role of ozone: Unlike oxygen, ozone is poisonous but it performs a very important role for us.

→ It forms a thick layer in the upper regions of the atmosphere and absorbs harmful radiation from the sun.

→ This prevents those harmful radiations from reaching the surface of the Earth where they may damage many forms of life.

→ CO₂ forms 95-97% of the atmosphere on Venus and Mars.

→ On the moon, the temperature ranges from -190°C to 110°C.

→ Smog formed by smoke and fog is a visible indication of air pollution.

→ Exhaustible Resources: These resources are limited in nature and will finish sooner or later.

→ Inexhaustible resources: These resources are unlimited and cannot be exhausted by man’s consumption.

→ Renewable resources: These resources are naturally replenished after man’s consumption.

→ Non-Renewable Resources: These resources cannot be replaced after they are used.

→ Underground Water: The water present below the soil is called underground water.

→ Crust: Topmost surface of the earth is called the crust.

→ Mineral resources: These resources are present on earth and are non-renewable.

→ Atmosphere: It is a transparent gaseous envelope surrounding the earth.

→ Pollution: It is an undesirable change in physical, chemical, or biological characteristics of the water and soil.

→ Acid rain: When gases like SO₂ and SO₃ react with water to form sulphuric acid and sulphurous acid and precipitate as rain is called acid rain.

→ Smoke: It is a secondary pollutant produced as a result of reactions of products of incomplete combustion.

→ Smog: Combination of smoke and fog forms smog (Smoke + fog = Smog).

→ Aerosoles: Certain chemicals are released in the air with force in the form of mist or vapour.

→ Soil: The topmost fertile layer of the earth capable of supporting plant growth is called soil.

→ Fertility of soil: The capacity of the soil to sustain plant life with required nutrients is called the fertility of the soil.

→ Water covers 75% of the earth’s surface.

→ NGO: Non-Governmental Organisation.

→ IUCN: International Union For Conservation of Nature and Natural Resources.

This PSEB 9th Class Science Notes Chapter 13 Why Do We Fall Ill will help you in revision during exams.

PSEB 9th Class Science Notes Chapter 13 Why Do We Fall Ill

→ According to WHO, health is a state of complete physical, mental and social well-being, and not merely an absence of disease or infirmity.

→ Health is a state of being well enough to function well physically, mentally, and socially.

→ Good health is characterized by – the absence of disease, free from social and psychological tensions, self-confidence, and efficient working.

→ Good health brings all-around progress and is the real wealth of an individual.

→ Good health is adversely affected by – overpopulation, environmental pollution, poverty, ignorance, unhealthy sexual life, etc.

→ Personal health includes four aspects: Personal cleanliness, exercise, rest, and healthy habits.

→ Basic conditions for maintaining good health are a Balanced diet; proper habits; exercise and relaxation habits, clean food, air, and water; avoiding hazardous substances; proper education, etc.

→ Different organs of different systems show interactions and interdependence.

→ The supply of food is a must for the proper functioning of organs to keep a person healthy.

→ Diseases are classified as acute or chronic, depending on their duration.

→ The disease may be due to infectious or non-infectious causes.

→ Infectious agents belong to different categories of organisms and may be unicellular and microscopic or multicellular.

→ On the basis of period of occurrence, diseases are of two types: Congenital (inborn diseases e.g. Haemophilia, Albinism) and acquired (during one’s own life span) diseases.

→ Acquired diseases are of two types on the basis of their communication: Communicable (which can be transmitted from diseased person to healthy persons) and Non-communicable diseases.

→ Communicable diseases are also called infectious diseases as these occur due to successful infection of the pathogenic (disease-causing) micro-organisms.

→ Infectious diseases can be prevented by public health hygiene measures that reduce exposure to infectious agents.

→ Common examples of diseases caused by viruses are common cold, influenza, dengue fever, and AIDS.

→ Typhoid fever, T.B., cholera, and anthrax are caused by bacteria.

→ Skin infections are caused by fungi.

→ Malaria, Kala Azar, sleeping sickness are caused by protozoans.

→ Ascariasis and elephantiasis are caused by worms.

→ AIDS, Syphilis, and Gonorrhoea are sexually transmitted diseases.

→ Principles of Prevention: Following three limitations are normally confronted while treating an infectious disease:

• If a person has a disease, his/her body functions are damaged and may never recover completely.
• Treatment will take time, which means that person suffering from a disease is likely to be bedridden for some time even if given proper treatment.
• The person suffering from an infectious disease can serve as the source from where the infection may spread to other people.
• It is because of such reasons that the prevention of diseases is better than their cure.

→ Some common vaccines:

• DPT vaccine for protection against diphtheria, whooping cough, and tetanus.
• BCG vaccine for protection against tuberculosis.
• Polio (OPV) vaccine.
• Typhoid vaccine.
• Measles vaccine.
• TT vaccine against tetanus.
• Hepatitis A and Hepatitis B for protection against jaundice.

→ Pulse Polio is an immunization campaign established by the Government of India in 1994 to eradicate poliomyelitis (polio) in India by vaccinating annually all children under age five against polio.

→ These vaccines form the public health program of childhood immunization for preventing infectious diseases.

→ Infectious diseases can also be prevented by using immunisation.

→ Effective prevention of infectious diseases in the community requires that everyone should have access to public hygiene and immunisation.

→ Vaccine against Hepatitis A is also available in our country.

→ August 20 is observed as ‘Malaria Day’.

→ December 1 is observed as ‘World AIDS Day’.

→ March 24 is observed as ‘World TB Day’.

→ The incidence of diarrhoeal disease is highest in Andhra and Orissa states.

→ Helicobacter pylori are responsible for peptic ulcers.

→ Bacteria Staphylococcus can cause acne.

→ Trypanosoma, a protozoan organism can cause sleeping sickness.

→ Health: It is a state of physical, mental, and social well-being.

→ Acute disease: Diseases that occur very rapidly, but occur for short period.

→ Chronic diseases: Diseases that last for long period and cause prolonged poor health.

→ Communicable diseases: These are transmitted from one man to another. These diseases are caused by viruses, Bacteria, Protozoa, Fungi, and Worms.

→ Non-Communicable diseases: The diseases which are not transmitted from an infected person to the other are called non-communicable diseases.

→ Antibodies: These are proteinic substances produced by the body in response to antigens and protect the body from damage.

→ Malnutrition: Defective nutrition due to inadequate intake of nutrients or due to faulty digestion or absorption or metabolism.

→ Allergy: Hypersensitive condition of the body in response to certain substances is termed allergy.

→ Disease: Any condition which interferes with the normal functioning of the body.

→ Acquired diseases: Diseases developed during own life span.

→ Congenital diseases: Inborn diseases which occur from birth.

→ Vaccination: A preventive inoculation that prevents the occurrence of disease by stimulating the immune system.

→ Therapy: Treatment of diseases.

This PSEB 9th Class Science Notes Chapter 12 Sound will help you in revision during exams.

PSEB 9th Class Science Notes Chapter 12 Sound

→ Sound is a kind of energy that produces a sensation of hearing in our ears.

→ Sound is produced due to vibrations of an object, Vibration means the to and fro movement of an object.

→ In human voice, the sound is produced due to the vibration of the larynx.

→ The substance through which sound travels is called medium.

→ Wave is a sort of disturbance.

→ For transmission of sound, a medium is required and the air is generally used as a medium.

→ Sound can not travel through a vacuum.

→ In transverse waves, the particles of the medium vibrate in a direction perpendicular to the direction of propagation of the wave.

→ The distance between two consecutive rarefactions is called wavelength.

→ The movement of compressions passing through a point in a unit of time is called frequency.

→ The time taken by two consecutive compressions or rarefactions passing through a fixed point is called the frequency of the wave.

→ The relation between velocity (υ), frequency (ν) and wavelength (λ) of the wave is υ = ν × λ

→ The velocity sound depends mainly upon the nature of medium and temperature.

→ To hear an echo the minimum time elapsed between the original sound and reflected sound should be 0.1 seconds.

→ Sound energy passing through a unit area in 1 second is called the intensity of sound.

→ The human audible range is 20 Hz to 20 kHz.

→ Sound travels through a substance in the form of longitudinal waves.

→ Sound travels through air medium in the form of compressions and rarefactions.

→ Compression is a region of high pressure and maximum density.

→ Sound: It is a kind of energy that produces in us the sensation of hearing.

→ Amplitude: The maximum displacement of the particle of the medium on either side of its mean position during vibration is called its Amplitude.

→ Frequency: The number of vibrations made by the vibrating body in 1 second is called its frequency.

→ Wavelength: Whatever time is taken by the particle to complete 1 vibration during the same time the distance travelled by the wave is called wavelength. It is denoted by ‘λ’.

→ Wave velocity: In a medium, the magnitude of the product of frequency and wavelength of a wave is equal to wave velocity i.e. υ = ν × λ

→ Oscillation or Vibration: The to and fro motion of a vibrating particle about its mean position to complete 1 vibration is called oscillation or vibration.

→ Periodic motion: The motion which is repeated after a fixed interval of time is called periodic motion,

→ Rarefaction: In longitudinal waves, the region where the particles of the medium are farther apart than the normal distance is called rarefaction. Here the pressure is lower than normal.

→ Echo: The reflected sound is called echo.

→ Transverse waves: Those waves in which the particles of the medium vibrate about their mean position in a direction perpendicular to the direction of propagation of the wave, such waves are called transverse waves.

→ Longitudinal waves: Those waves in which the particles of the medium vibrate forward and backward in the same direction in which the wave travels then the wave is called a longitudinal wave.

→ Ultrasonic waves: Those longitudinal waves which have a frequency of more than 20000 Hertz (Hz) are called ultrasonic waves.

→ SONAR (Sound Navigation and Ranging): It is a device that measures the time for producing sound waves and reflected waves.

→ Time Period: The time taken to complete one complete vibration (i.e. to travel from mean position to one extreme position than to other extreme position and back is called time period. It is denoted by ‘T’ and expressed in seconds.

→ Compression: Due to the forwarding motion of the longitudinal wave, the region where the particles of medium come close to each other than the normal distance between them is called compression. Here the pressure is higher than normal.