Extra Questions for Class 9 Science

Extra Questions for Class 9 Science CBSE Notes for Extra Questions for Class 9 Science CBSE Extra Questions for Class 9 Science gives you the right study material to excel in your studies in 9th grade. A good foundation in Class 9 can help you with your board exams in class 10 and can play a significant role in your future careers as well. In Class 9, Science can be a challenging subject to learn. Students will have to understand the concepts of physics, chemistry, and biology in-depth so that the foundations they have to move onto more complex topics in the future are strong enough. The student will need to understand the various E ​ xtra Questions for Class 9 Science​ so that they have an idea of what to expect in their final exams and the boards in the next year.

● ● ● ● ● ● ● ● ● ●

Matter in Our Surroundings Class 9 Extra Questions Is Matter Around Us Pure Class 9 Extra Questions Atoms and Molecules Class 9 Extra Questions Structure of the Atom Class 9 Extra Questions The Fundamental Unit of Life Class 9 Extra Questions Tissues Class 9 Extra Questions Diversity in Living Organisms Class 9 Extra Questions Motion Class 9 Extra Questions Force and Laws of Motion Class 9 Extra Questions Gravitation Class 9 Extra Questions

● ● ● ● ●

Work, Power And Energy Class 9 Extra Questions Sound Class 9 Extra Questions Why Do we Fall Ill Class 9 Extra Questions Natural Resources Class 9 Extra Questions Improvement in Food Resources Class 9 Extra Questions

1. Matter in Our Surroundings Class 9 Extra Questions CBSE Notes for Matter in Our Surroundings Class 9 Extra Questions Anything that has mass and occupies space is called matter. The matter is made up of particles. These particles are so small that they cannot be seen with naked eyes. They have spaces between them and they are in a state of constant motion. The particles of matter are held together attractive forces. On the basis of differences in the physical characteristics of the particles of the matter, matter exists in three states namely solid, liquid and gaseous state.

Diffusion is the process of movement of particles from the region of their high concentration to the region of low concentration. Factors which affect the rate of diffusion are the nature of substance and temperature. Please refer M ​ atter in Our Surroundings Class 9 Extra Questions​ for more information.

2. Is Matter Around Us Pure Class 9 Extra Questions CBSE Notes for Is Matter Around Us Pure Class 9 Extra Questions The matter is anything that occupies the space and has a certain mass. Matter can be impure or pure. Impure matter is a mixture of many pure substances. The mixture contains more than one kind of pure form of matter in which their constituents do not lose their identity. Mixtures are of two types; homogeneous and heterogeneous mixture. A homogeneous mixture is a mixture that has a uniform composition throughout. A solution is

a type of homogeneous mixture. Alloys are homogeneous mixtures of two or more metals or a metal and non-metals. The solution is a homogeneous mixture of two or more substances. The heterogeneous mixture does not have uniform composition throughout.

Please refer I​ s Matter Around Us Pure Class 9 Extra Questions​ for more information.

3. Atoms and Molecules Class 9 Extra Questions CBSE Notes for Atoms and Molecules Class 9 Extra Questions Atoms and molecules An atom is the smallest particle of the element that can exist independently and retain all its chemical properties. Atom can take part in a chemical reaction. Atoms can exist either as molecules or as ions. The molecule is an electrically neutral group of two or more atoms chemically bonded together. The molecules of an element contain two or more atoms chemically combined together. The number of atoms constituting a molecule is known as its atomicity. Depending upon the atomicity, a molecule of an element can be classified into a monoatomic molecule, diatomic molecule, triatomic m molecule, tetra-atomic molecule, and polyatomic molecule. Please refer A ​ toms and Molecules Class 9 Extra Questions​ for more information.

4. Structure of the Atom Class 9 Extra Questions CBSE Notes for Structure of the Atom Class 9 Extra Questions Atomic Models Everything around us is made up of tiny particles called atoms. There are three subatomic particles namely electron, proton, and neutron. Electron (e–1) was discovered by J.J. Thomson. It carries one unit of negative charge. Proton (p+) was discovered by Goldstein. It carries one unit of a positive charge. Neutron (n0) was discovered by J. Chadwick. It is a neutral atomic particle. To describe the arrangement of subatomic particles within the atom, many models of an atom are proposed. Some of them are Thomson’s Model, Rutherford’s Model, Bohr’s Model. Thomson’s Model is also known

as the watermelon or the plum pudding model as the electrons in the sphere of the positive charge were just like dry fruits in a spherical Christmas pudding. Rutherford’s alpha-particle scattering experiment led to the discovery of the nucleus of an atom. Rutherford’s model of the atom proposed that a very tiny nucleus is present inside the atom and electrons revolve around this nucleus. Please refer S ​ tructure of the Atom Class 9 Extra Questions​ for more information.

5. The Fundamental Unit of Life Class 9 Extra Questions CBSE Notes for The Fundamental Unit of Life Class 9 Extra Questions A Cell is the structural and functional unit of all the living organisms, which is capable of carrying out all life processes. Robert Hooke observed honeycomb-like compartments, the microscope and named them ‘cells’. They were dead cells. In 1674, Leeuwenhoek discovered living cells in pond water. The cell theory was presented by two biologists – Schleiden (1838) and Schwann (1839). It was further expanded by Virchow (1855). There are two types of organisms based on the number of cells present in them: • Unicellular organisms: They are single-celled. For example Mycoplasma, Amoeba • Multicellular organisms. They possess two or more c cells for example plant and animal cells. Cells are enclosed by a plasma membrane. Please refer T ​ he Fundamental Unit of Life Class 9 Extra Questions​ for more information.

6. Tissues Class 9 Extra Questions CBSE Notes for Tissues Class 9 Extra Questions A tissue is a group of cells that are similar in structure and perform a specific function.

There are two types of tissues, i.e., Plant tissue and animal tissue. Plant tissues are further divided into two types, meristematic and permanent tissues. On the basis of the location of the meristematic tissue, it is divided into three types, i.e., apical, intercalary and lateral

meristem. Permanent tissues are classified as simple and complex tissues. There are three types of simple tissues: Parenchyma, collenchyma, and sclerenchyma. There are two types of complex tissues, xylem, and phloem. Xylem tissue is made of four kinds of cellular components s namely tracheids, vessels, xylem parenchyma, and xylem fibers. While, phloem tissue consists of sieve tubes, companion cells, phloem parenchyma, and phloem fibers. Animal tissues are classified as epithelial, connective, muscular and nervous tissue.

On the basis of shape and function, epithelial tissue is classified as squamous, cuboidal, columnar, ciliated and glandular. Please refer T ​ issues Class 9 Extra Questions​ for more information.

7. Diversity in Living Organisms Class 9 Extra Questions CBSE Notes for Diversity in Living Organisms Class 9 Extra Questions Classification helps us in exploring the diversity of life forms. In the classification system, organisms are classified as follows: Kingdom phylum class order family genus species All living organisms are classified into five kingdoms, namely: Monera, Protista, Fungi, Plantae, and Animalia.

• Kingdom Monera includes unicellular, prokaryotic organisms with autotrophic or heterotrophic nutrition.

• Kingdom Protista includes unicellular, eukaryotic organisms with autotrophic or heterotrophic nutrition.

• Kingdom Fungi includes unicellular or multicellular, eukaryotic organisms with heterotrophic nutrition.

• Kingdom Plantae includes multicellular, eukaryotic organisms with cell walls. They are capable of producing their own food by photosynthesis.

• Kingdom Animalia includes multicellular, eukaryotic organisms without cell walls. As per the five-kingdom classification, the Kingdom Plantae and Animalia are further classified into

subdivisions on the basis of the increasing complexity of body organization. Please refer Diversity in Living Organisms Class 9 Extra Questions ​for more information.

8. Motion Class 9 Extra Questions CBSE Notes for Motion Class 9 Extra Questions Motion is the change in the position of an object with respect to its surroundings. It can be described in terms of the distance moved by an object or its displacement. The rate of motion can be determined by measuring the distance traveled in unit time. This is referred to as speed. It makes more sense if we mention the direction of motion along with its speed to define the rate of motion. This quantity is called velocity, which is given by the displacement per unit time. Moreover, the rate of change of velocity with time is known as acceleration. An object can either move in uniform or non-uniform motion. If the velocity of the object is constant with time, then its motion is said to be uniform. Please refer M ​ otion Class 9 Extra Questions​ for more information.

9. Force and Laws of Motion Class 9 Extra Questions CBSE Notes for Force and Laws of Motion Class 9 Extra Questions Force is a push or pulls that can change the state, shape, size or velocity of an object.

Forces can be broadly divided into balanced and unbalanced forces. If the resultant of all the forces acting on an object is zero, then the forces are called balanced forces. If the resultant of all the forces acting on an object is non-zero, then the forces are known as unbalanced forces. Only the unbalanced forces can change the state of rest or motion of an object. The motion of the objects is governed by Newton’s three laws of motion. Please refer F ​ orce and Laws of Motion Class 9 Extra Questions​ for more information.

10. Gravitation Class 9 Extra Questions

CBSE Notes for Gravitation Class 9 Extra Questions Gravitation refers to the force of attraction between any two objects due to their masses.

This force of attraction can be given by universal law of gravitation, which states that the force of attraction between any two bodies is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. Force of gravitation due to the earth is called gravity. Whenever an object falls under the force of gravity alone, it is said to be in free fall. The force with which the earth attracts the object towards it gives the weight of the object. It is different from the mass of the object, which r refers to the total quantity of matter contained in the object. Please refer G ​ ravitation Class 9 Extra Questions​ for more information.

11. Work, Power And Energy Class 9 Extra Questions CBSE Notes for Work, Power And Energy Class 9 Extra Questions Work is said to be done on a body when the non-zero force acting on it displaces it in the direction of the applied force. When the direction of applied force and that of the displacement of the object are the same, the work done on the object is said to be positive.

When the direction of the applied force and that of the displacement of the object are opposite to each other, the work done on the object is said to be negative. Work done on a body is said to be zero if the non-zero force acting on it produces zero displacements.

Please refer W ​ ork, Power And Energy Class 9 Extra Questions​ for more information.

12. Sound Class 9 Extra Questions CBSE Notes for Sound Class 9 Extra Questions A sound is a form of energy which produces a sensation of hearing in our ears. It is produced due to the vibration of different objects. Sound waves are longitudinal waves and propagate in a medium in the form of compressions and rarefactions. These waves cannot

travel in a vacuum. A sound wave can be described by its three important properties i.e., frequency, amplitude, and speed. It can be reflected at the surface of a solid or a liquid and follows the laws of reflection, like a light. The repetition of sound caused by the reflection of sound waves by a tall building or a mountain is known as an echo. The time interval between the original sound and reflected one should be at least 0.1 s in order to hear a distinct sound. However, the persistence of sound due to the repeated reflections of sound is known as reverberation. Human beings and most of the animals are able to hear with the help of a sense organ, called the ear. It consists of three basic parts - the outer ear, middle ear, and inner ear. Please refer S ​ ound Class 9 Extra Questions​ for more information.

13. Why Do we Fall Ill Class 9 Extra Questions CBSE Notes for Why Do We Fall Ill Class 9 Extra Questions Health is a state of physical, mental and social well-being. The health of the organism is determined by environmental factors. Environmental factors include social as well as physical factors. The word disease means “disturbed ease”. A symptom of a disease is a definite indication of the presence of a particular disease. Diseases are classified as acute or chronic, depending on their duration. Based on communicability, diseases are classified as infectious and non-infectious. Infectious agents spread through the air, water, physical contact or vectors.

• Bacteria that cause tuberculosis, typhoid, anthrax, cholera, etc • Viruses that cause the common cold, influenza, dengue, AIDS, brain fever (Japanese encephalitis) • Protozoans that cause kala-azar, malaria, etc • Worms that cause elephantiasis etc Causes of the disease can be immediate or contributory.

A disease may be caused due to factors like: • Pathogens or infectious agents • Poor nourishment

• Genetic abnormalities • Lack of public services Our immune system fights against the diseases. Activation of the immune system against infectious diseases results in inflammation and fever. Please refer Why Do We Fall Ill Class 9 Extra Questions​ for more information.

14. Natural Resources Class 9 Extra Questions CBSE Notes for Natural Resources Class 9 Extra Questions Life on Earth depends on various factors. The natural resources available on the Earth and the energy from the Sun are necessary to meet the basic requirements of all the living organisms on the Earth. The atmosphere plays an important role in controlling the temperature of the Earth. The heating of air over land and water-bodies causes winds. The evaporation of water from water-bodies and subsequent condensation causes rain. The rainfall patterns depend upon the wind prevailing in an area. A constant interaction between the biotic and abiotic components of the biosphere makes it a dynamic, but a stable system. Various nutrients in the environment are used again and again in a cyclic fashion by the process of the biogeochemical cycle. This leads to a certain balance between the various components of the biosphere. Pollution of air, water, and soil affect the quality of life and harm the environment. Some of the harmful effects are ozone layer depletion, the greenhouse effect, etc. We need to use our resources in a sustainable manner because these are not unlimited and the demand for all resources is increasing. Please refer ​Natural Resources Class 9 Extra Questions​ for more information.

15. Improvement in Food Resources Class 9 Extra Questions CBSE Notes for Improvement in Food Resources Class 9 Extra Questions India is a very populous country. The efforts have been made to meet the food demand by increasing food production. The varieties of crops are selected by breeding method for

various useful characteristics such as disease resistance, response to fertilizers, product quality and high yields. Nutrients play an important role in the growth and development of crops. There are thirteen nutrients essential for crops. Some nutrients are required in large quantities and are known as macronutrients and some nutrients are required in small quantities and are known as micronutrients. Manure contains large quantities of organic matter while the fertilizers are commercially produced artificial nutrients. In mixed cropping, two or more crops are grown simultaneously on the same piece of land. The method of growing two or more crops in definite row patterns is known as inter-cropping. Please refer Improvement in Food Resources Class 9 Extra Questions​ for more information.