Class 10 Science NCERT Notes:

Class 10 is an important stage of academic life and can be one of the determinants of future direction in terms of career. Science is scoring as a subject, provided one has a good understanding of the basics of the subject. CBSE Class 10 Science NCERT contains various chapters, some of which are:

  • Chemical substances
  • World of Living
  • Natural Phenomena
  • Effects of Currents
  • Natural Resources

Let’s do a quick revision of the Class 10 Science NCERT chapters now.

Chemical Reactions and Equations

Chemical reactions

Chemical reactions can be described as the processes wherein new substances with new properties are formed.

Here are some key points on chemical reactions:

  • In a chemical reaction, only a rearrangement of atoms happens.
  • The substances that are a part of a chemical reaction are known as reactants.
  • The new substances that get formed as a result of a chemical reaction are called products.
  • In a chemical reaction, reactants get transformed into products.
  • The instance of burning of magnesium in the air to form magnesium oxide is the perfect explanation of a chemical reaction.
  • When it comes to the conversion of reactants into products in a chemical reaction, it is more often than not accompanied by some features that can be easily observed.

The important features of chemical reactions are:

  1. Evolution of a gas
  2. Formation of a precipitate
  3. Change in colour
  4. Change in temperature
  5. Change in state

Chemical equations

  • The overall process of representing a chemical reaction with the help of symbols and formula of the substances that are a part of it is called a chemical equation.
  • Zinc metal reacts with dilute sulphuric acid to form zinc sulphate and hydrogen gas.
  • This is called word equation. When we put the symbols and formula of all the substances in the above word equation, we can get the following chemical equation:
  • The substances that are combined or react together are called reactants.
  • The new substances that get produced in a reaction are called products.
  • A chemical equation is nothing but a short-hand method of representing a chemical reaction.

Control and Coordination

To begin with we need to understand a plant hormone, which is nothing but a chemical substance that gets produced naturally in plants.  It also regulates growth and physiological processes to bring about control and coordination of various activities in plants.

The plant hormones are responsible for regulating many functions in plants like the following:

  • growth of root, stem and leaves (cell division, cell elongation and cell differentiation)
  • growth of fruits
  • opening and closing of stomata
  • germination of seeds
  • flowering of plant etc.

There are 4 main kinds of plant hormones that are involved in the control and coordination in plants:

  1. Auxins
  2. Gibberellins
  3. Cytokinins
  4. Abscisic acid (ABA)
PLANT HORMONE FUNCTIONS
Auxins Promote cell differentiation and cell enlargement.
Promote fruit growth. (the reason behind the phototropic and geotropic responses in plants).
Gibberellins Promote cell enlargement and cell differentiation in the presence of auxins.
Promote fruit growth.
Help in breaking dormancy of seeds and buds.
Cytokinins Promote cell division.
Promote fruit growth.
Aid in breaking dormancy of seeds and buds.
Delay the ageing in leaves.
Promote opening of stomata.
Abscisic acid (ABA, growth inhibitor) Promote the dormancy of seeds and buds.
Promote closing of stomata.
Promote the wilting and falling of leaves.

How Do Organisms Reproduce?

The overall process wherein there is a production of a new organism from the existing organism of the same species is known as reproduction.
Keep in mind that reproduction is crucial for the survival of species on this earth. The entire process of reproduction helps maintain continuity of life on earth. Reproduction is responsible for producing more organism with the same basic characteristics as their parents.

Types of Reproduction

Primarily, there are two types of reproduction in living.

  1. Asexual reproduction

Asexual reproduction is simply the production of a new organism from a single parent without the involvement of sex cells (or gametes).

2. Sexual reproduction

It is the process of production of new organisms from two parents with the use of sex cells.

Light Reflection and Refraction

Understanding Reflection of Light

  • The complete process of sending back light rays that fall on the surface of an object is known as the REFLECTION of light
  • Silver metal is a great and one of the best reflectors of light.
  • Mirrors that we use daily on our dressing tables are plane mirrors.
  • ray of light can be defined as the straight line along which the light travelled and a beam of light is a bundle of light rays.

Laws of Reflection of light

  1. The angle of incidence is equal to the angle of reflection
  2. The incident ray, the reflected ray and the normal to the mirror at the point of incidence all lie in the same plane.

Understanding Refraction of Light

  • We all know about light and also are aware of the fact that light travels in a straight line path in a medium or two different mediums with the same density.
  • Now the crucial question remains: what happens when light travels from one medium to another with different densities for example from air to glass? When the light ray travels from one medium to another, let’s assume from air to glass medium, then, in this case, light rays bend at the boundary between the two mediums.
  • So, we can define the bending of light when it passes from one medium to another as the Refraction of light.
  • The refraction of light happens when going from one medium to another because the speed of light is different in two media.
  • Please note:- When light travels from a rarer medium to a denser medium, then it bends towards the normal. However, it bends away from the normal when it goes from denser medium to rarer medium. 

Acids, Bases, and Salts

Acids are substances which release a hydronium ion in their aqueous solutions. They are characterized by their sour taste and ability to turn a litmus paper red. Bases are substances which release a hydroxyl ion in solution. They are bitter in taste and soapy to touch. Salts are those compounds which are formed by the neutralization reaction of acids and bases, having a positive action and a negative action. The salt is generally neutral.

Metals and Non-metals

Metals and nonmetals are elements which are the basic components of almost all things around us. Metals are generally good conductors of electricity, solids at room temperature (except mercury), malleable and ductile, lustrous, electropositive in nature and have high densities. Nonmetals are generally bad conductors of electricity, exist in three states, not as hard as metals and are generally soft, generally non-lustrous, and have low densities. Metals and nonmetals are arranged based on their atomic weight in the Periodic Table.

Classification of Elements in the Periodic Table

The Periodic Table is an arrangement and classification of elements based on their atomic weight. Elements generally show periodicity in their properties, that is, they show similar properties. Thus, the periodic table groups similar elements in a sequentially coherent manner so that studying the elements and discussing their properties becomes easy. The Periodic Table enables easy classification of elements. Elements can be added to the periodic table as and when they are discovered.

Life Processes

Life processes are those biological processes which enable life to survive. The important life processes are respiration, nutrition, metabolism, excretion, transportation, and reproduction. Respiration supplies oxygen and removes carbon dioxide from the body. Nutrition supplies food which is broken down to provide energy for bodily functions. Metabolism is the breakdown of complex food particles into simpler absorbable forms, absorption of nutrients and assimilation and storage of nutrients for purpose of energy production. Excretion is the removal of bodily waste products from the system as and when necessary. Transportation is responsible for the movement of the organism in search of food, shelter and for reproduction. Reproduction enables the transmission of genetic material and perpetuation of the species over time.

Heredity and Evolution

Heredity is the transmission of somatic and genetic, physiologic and psychologic characteristics of parents to offspring and from one generation to the next. Heredity occurs by transmission of genetic material as well as epigenetic factors.  Evolution is the gradual development and transformation of one life form into another from more primitive undifferentiated simpler life forms to more specialized differentiated and complicated life forms. Evolution occurs via heredity, mutation, natural selection etc.

The Human Eye and the Colorful World

The Human eye is a unique sense organ which enables us to visualize the world around us and enables us to make sense of what goes around us by collecting visual information from the surroundings. The eye is an end organ. It has various parts like eyelids, cornea, eyeball, iris, lens, external and internal muscles, blind spot and optic nerve. The eye has specialized nerve endings called rods and cones which enable us to see in a bright and dim light as well as perceive the various shades of different color around us. The optic nerve carries visual information to the brain for interpretation. The lens can be replaced. The cornea can be donated after death which, after replantation enables the recipient of the donation a new sight. It is a very noble deed.

Electricity

Electricity or electric current is the moving electric energy from one place to another. An electric current is made of multiple charges in motion. The flow of electricity is dependent on the potential difference between the terminals where the current is flowing and the resistance of the unit through which the electric charge is flowing. It is also dependent on circuit configuration, temperature, nature of the circuit material etc.

Magnetic Effects of Electric Current

From chapter ‘electricity’, we all by now know something about electric field E⃗  and how it gets produced at all points around it. So, just like that, magnets also create a magnetic field at all points around it. An electric current going through a wire behaves like a magnet.

Hans Christian Oersted (1777-1851) proved that electricity and magnetism are related to each other through his experiments. His research was later extensively used in radio, television, etc. The unit of magnetic field strength has also been named Oersted in his honour.

Sources of Energy

Source of energy can be described as anything that is capable of supplying us useful energy for carrying out the various activities like:
(i) Heat energy for cooking purposes
(ii) Electrical energy for lighting up a room.
(iii) Muscular energy for carrying a bag and running bicycle
(iv) Sound energy for calling up friends.

A good source of energy possesses these characteristics:
(i) It manages to do a large amount of work per unit volume or mass.
(ii) It is always easily accessible.
(iii) It can be easily stored and transported to another place.
(iv) It is economical.

Our Environment

Our ecosystem is made up of a non-living environment and a living biological community. The non – living environment comprises components like water, carbon dioxide, phosphorus, oxygen, nitrogen, and the other elements. Whereas, the living community is made up of plants, animals, etc.

There are some substances in this ecosystem that can be acted upon by the microorganism and broken down into simple substances. These substances are basically biodegradable. And the other substances that are inert and cannot be decomposed by microorganisms and do not break down into simple substances are called non–biodegradable.

Biodegradable substances affect the environment in a lot of ways:
(i) Firstly, they get decomposed by the action of microorganisms, causing a foul smell.
(ii) During the process of decaying of biodegradable substances, a lot of gases get released that eventually cause air pollution.

The non-biodegradable substances also affect the environment in a lot of ways:
(i) they remain in the environment for a long time and are responsible for damaging the environment.
(ii) They cause land pollution and water pollution.

Management of Natural Resources

Natural resources are finite resources. Their utilization comes with the rider that they are going to be finished at some point in time. Thus it is quite important to manage their use properly and not overuse them, so as to make the resources sustainable and long-lasting. Resources like coal, freshwater, soil, land, green cover etc are finite resources and should be handled with care keeping in mind their propensity to be exhausted soon.

Carbon and its Compounds

Carbon is an element which is omnipresent. Carbon compounds literally make us up, make the food that we eat, the clothes that we wear, the paper that we read, the plastics that we use and so on. Carbon is the 17th most abundant element present on earth. It is found both free and in the combined state. Carbon has a propensity to make long chains and ring structures. It makes double and triple covalent bonds with itself which adds to the variability of carbon compounds and also influences physical and chemical properties.

NCERT Class 10 Science Solutions

Chapter 1 – CBSE-10-Chemistry-Chemical-Reactions-and-Equations

Chapter 3 – CBSE-10-Chemistry-Metals-and-Non-metals

Chapter 4 – CBSE-10-Chemistry-Carbon-and-its-Compounds

Chapter 5 – CBSE-10-Chemistry-Periodic-Classification-of-Elements

Chapter 6 – CBSE-10-Biology-Life-Processes

Chapter 7 – CBSE-10-Biology-Control-and-Coordination

Chapter 8 – CBSE-10-Biology-How-Do-Organisms-Reproduce

Chapter 9 – CBSE-10-Biology-Heredity-and-Evolution

Chapter 10 – CBSE-10-Physics-Light-Reflection-and-Refraction

Chapter 11 – CBSE-10-Physics-Human-Eye-and-Colourful-World

Chapter 12 – CBSE-10-Physics-Electricity

Chapter 13 – CBSE-10-Physics-Magnetic-Effects-of-Electric-Current

Chapter 14 – CBSE-10-Physics-Sources-of-Energy

Chapter 15 – CBSE-10-Biology-Our-Environment

Chapter 16 – CBSE-10-Biology-Management-of-Natural-Resources

To do some revision on related scientific areas, visit here.

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