Quiz on human eye
Loading… See also-HUMAN EYE AND COLOURFUL WORLD / WONDERS OF LIGHT PART – I
Quiz on Laws of motion
Loading… See also-Force and Laws of Motion – Balanced and Unbalanced Force, Inertia, Types of Inertia
Quiz on scalar , vector quantity, uniform motion, nonuniform motion,moving objects
Loading… See also- What is Uniform and Non-uniform Motion? Give Examples.
Property of Sound Waves that Sound needs Material Medium to Travel
The sound waves need material medium to travel because they travel by the vibrations of particles of the medium. The material medium is gas, liquid and solid. Sound waves are called mechanical waves as they need a material medium for their travel. An activity described below tells that sound can not travel through vacuum. The …
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Work, Energy, Power – Question and solution
A body of mass 20 kg is projected vertically upwards with a velocity of 20m/s. Find – (a) its potential energy at the starting point (b) its kinetic energy at the starting point (c) its potential energy at the highest point (d) its kinetic energy at the highest point. Answer – (a) its potential energy …
Print Command in Python
print() statement: The print() statement is a very important statement in the language of Python. This command is used to print a variety of things. It can be used in conjunction with lists, strings, integers, tuples and dictionaries (it can also do calculations). It takes three kinds of arguments: value(s) to be printed Eg: >>>print(‘hello. …
Introduction to Python
Pythons are very powerful and very flexible creatures, as we all know. In the same way, we find that the language Python is also very powerful and flexible. Python is an open source, object-oriented, high level programming language which was developed by Guido van Rossum in 1991. The language is based on the ABC language(yes …
Build an Atom / Element / Ion
This is an interactive activity.
As we know, an atom is the smallest building block of everything that exists. It is composed of three sub-atomic particles: the proton, neutron, and electron.
1.1 ATOM – Significance of Sub-atomic Particles
What is an atom? What is the significance of sub-atomic particles- Proton, neutron and electron? Quiz – Build an Atom / Element / Ion As we know, an atom is the smallest building block of everything that exists. It is composed of three sub-atomic particles: the proton, neutron, and electron. Protons and neutrons make up …
Life Processes / Life’s Internal Secrets – Transportation
Quiz – Previous Years’ CBSE Board Questions – Class X – Life Processes – Transportation _______________________________________________________________________________________________ Quiz – Previous Years’ CBSE Board Questions – Class X – Life Processes – Transportation
Previous Year’s CBSE Board Questions – Life Processes – Transportation
Transportation What will happen to a plant if its xylem is removed? (Delhi 2009, 1 mark) Need clues – Click here (a) Draw a sectional view of the human heart and level on it – Pulmonary arteries, vena cava, left ventricle.(b) Why is double circulation of blood necessary in human beings? (AI 2009, 5 marks) …
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Previous Year’s CBSE Boards Questions – Soaps and Detergents (Carbon and its Compounds)
Soaps and Detergents – Give reasons for the following observation – Use of synthetic detergents causes pollution of water. (1/3 mark, Delhi 2009) Need clue – Click Here Explain the cleansing action of soap. (2/5 marks, Foreign 2009) Need clue – Click Here Why does micelle formation take place when soap is added to water? …
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Some Important Carbon Compounds -Ethanol and Ethanoic acid
ASSESSMENT – CLICK HERE Previous Year’s CBSE Board Questions -Some Important Carbon Compounds – Ethanol and Ethanoic acid [googlepdf url=”https://freakgenie.com/wp-content/uploads/2019/02/carbon-compd-ethanol-and-ethanoic-acid.pdf” width=”100%” height=”2560″] ASSESSMENT – CLICK HERE Previous Year’s CBSE Board Questions -Some Important Carbon Compounds – Ethanol and Ethanoic acid
Previous Year’s CBSE Board Questions -Some Important Carbon Compounds – Ethanol and Ethanoic acid
Some Important Carbon Compounds – Ethanol and Ethanoic acid 1. Write the name and molecular formula of an organic compound having its name suffixed with ‘-ol’ and having two carbon atoms in its molecule. Write balanced chemical equation to indicate what happens when it is heated with excess of conc. H2S04 and the name of …
Difference between Asexual Reproduction and Sexual Reproduction
There are two methods of reproduction – (A) Asexual reproduction (B) Sexual reproduction (A) Asexual reproduction It involves only one individual (single parent). It takes place without gametes (sex cells) and fertilization. Cells divide mitotically. It is a simple process of cell division as shown below. Offsprings are genetically identical to the parents. E.g. Spirogyra …
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Heredity
Heredity is the passing of characters or traits from its parent or ancestors to their offspring. The study of heredity in biology is called genetics. It explains that organisms resemble each other because they arise from common ancestor. The offspring of cats are cats, fish are fish and humans are humans only. Trait – A …
Rutherford Experiment and Discovery of Nucleus
Lord Rutherford (1911) and his coworkers performed an experiment. They bombarded a very thin, gold foil with alpha particles from a radioactive source. They selected the gold foil because they wanted as thin a layer as possible. The gold foil was about 1000 atoms thick. It was expected that – (a) all alpha particles would …
Force and Laws of Motion – Balanced and Unbalanced Force, Inertia, Types of Inertia
When the sum of forces becomes zero, the forces balance each-other and the forces are called balanced forces. Activity – We take a box and tie two strings to it in opposite direction. One string is at end A and other string is at end B. When we pull string at A, the box moves …
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FORCE AND LAWS OF MOTION / THE LAWS OF MOTION – SUMMARY
Summary – If the resultant of all the forces acting on a body is zero, the forces are called balanced forces. If the resultant of all the forces acting on a body is not zero, the forces are called unbalanced forces. An unbalanced force acting on a body gives it an acceleration. Force is an …
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Common Behaviour of Acids and Bases
In the following section, we will find the answers of following questions- (i) All acids have similar chemical properties. All bases have similar chemical properties. What lead to this similarity in properties? (ii) How acids and bases are different chemically? Group A Group B ACIDS BASES Hydrochloric acid (HCl) Sodium hydroxide …
Thomson’s Model of an Atom
Thomson’s Model of an Atom was proposed in 1903 All matter is made of atoms and all the atoms are electrically neutral and it was known that all atoms contain the electrons. Based on these facts, Thomson concluded that – (a) an atom could be considered as a sphere of uniform positive charge in which …
Periodic Classification of Elements – Part – 1
Table of Contents – Need of Classification What is Periodic Table and Periodicity? Dobereiner’s Triads Newlands’ Law of Octaves
Importance and Limitations of Modern Periodic Table
Importance of Modern Periodic Table 1. Based on atomic number – The arrangement of elements in modern periodic table is according to their increasing order of atomic number. Atomic number increases by 1 unit (not fractional) in going from one element to the next element and equal to the number of electrons. Thus, the …
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Arrangements in Modern Periodic Table (Long Form of Periodic Table)
Table of Contents – Arrangement in Periodic Table Groups Periods Frequently asked Questions (FAQ’s) Next – Importance and Limitations of Modern Periodic Table The arrangement in periodic table is given by Bohr so it is also known as Bohr’s table or Long form of periodic table. This table is prepared on the basis of – …
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INTRODUCTION TO MODERN PERIODIC TABLE
Table of Contents – Introduction Why atomic number is better choice of classification than atomic mass? Modern Periodic Law Why periodicity in properties occur? How are electrons distributed in different orbits(shells)? Or How can be found electronic configuration of an element? The modern periodic table of elements is based on Mendeleev’s observations. The only difference …
Introduction to Organic Chemistry and Vital Force Theory
♦ Earth crust has only 0.02% carbon in the form of minerals (e.g. – carbonates, bicarbonates, coal, petroleum etc.) and atmosphere has 0.03% carbon dioxide. Inspite of its availability in such a small amount, it is highly important for our lives. ♦ Except water most of …
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Allotropes of Carbon
Carbon can exist in various physical forms in the nature with widely varying physical properties, but identical chemical properties. Such characteristic is called allotropy and the different forms are called allotropic forms or allotropes. The difference among allotropes lies in the manner in which the carbon atoms are bonded to one another. Allotropes are exclusively …
Why does Carbon always form Covalent Bond?
Carbon has four valence electrons. To attain noble gas configuration of the nearest noble or inert gas (He = 2 or Ne = 2,8), there are following possibilities – (1) It could gain 4 electrons and form C –4 anion. By that way, it can achieve noble gas configuration (Ne = 2,8) having 8 electrons in the …
Electron Dot Structure or Lewis Structure
In the Electron dot structural presentation, dots or crosses represent valence electrons which are put around an atom. Covalency of an atom is equal to the number of covalent bonds formed by the atom. Read First – Carbon and its Compounds – Introduction What is the Versatile Nature of Carbon? (a) When two atoms share one …
ATOMS AND MOLECULES – NCERT TEXT BOOK Questions Solutions
Science – Text Book for Class IX Page No. – 32 Q. In a reaction, 5.3 gm of sodium carbonate reacted with 6 gm of ethanoic acid. The products were 2.2 gm of carbon dioxide, 0.9 gm water and 8.2 gm sodium ethanoate. Show that these observations are in agreement with the law of conservation …
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WHAT IS FORMULA UNIT MASS OR FORMULA MASS?
The compounds which are formed by ions are called ionic compounds. In general, cations are made by metals and anions are made by non-metals. So, it can be understood as compounds made by metals and non-metals are ionic compounds. Examples – Al2(SO4)3, CaCl2, K2SO4, KNO3, CaCO3, NaCl, MgCl2 etc. Read more – Law of Conservation of …
How do you Write Chemical Formula for an Ionic Compound?
Rules for writing a chemical formula Write down the symbols of the ions (cation and anion) involved. Write the symbol of cation first (L.H.S) followed by the symbol of anion (R.H.S.). Write the valency of each ion. Interchange the valencies of the ions and write as the subscript. Write them close together and ignore ‘1’ …
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RULES FOR WRITING A CHEMICAL FORMULA OF SIMPLE COMPOUNDS
Chemical formula is a symbolic representation of a molecule’s composition. It indicates – (a) the elements that are present in the compound and (b) the ratio of these elements in the compound. A chemical formula is also called molecular formula. The symbols in the molecular formula tell us about the elements and the subscript tells …
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Problems / Numericals based on Mole Concept (Atomic Mass/ Molar Mass/ Avogadro number)
Formulas in brief – Mass = Molar mass x Number of moles Number of moles = Given number of particles / Avogadro number Number of particles = (Given mass / molar mass) x Avogadro number (from 1 and 2) If one carbon atom has a mass of 12 atomic mass units and one magnesium atom has …
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What is Mole Concept? – Introduction, Importance and Formulae
Introduction The structure of matter can be one of the following – atoms → molecules → bulk compound or element atoms → bulk element atoms → ions → bulk ionic compound It clearly shows that the masses that are measured in the laboratory are masses corresponding to large numbers of tiny atoms or molecules. Logically …
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Importance of Mendeleev’s Periodic Table
Read First – Mendeleev’s Periodic Table (1) Systematic Study of the elements Mendeleev’s periodic table was developed in accordance to- (a) increasing atomic masses. (b) grouping of similar elements together. By the way, the study of elements became quite simpler, as if properties of one element in a particular group were known, properties of others …
DISCOVERY OF CHARGED PARTICLES IN MATTER – Electron, Proton and Neutron
Read – Structure of the Atom / Inside the Atom – Summary Discovery of Electron – During 1890s’ many scientists performed experiments using cathode ray tubes. A cathode ray tube or discharge tube is made of glass from which most of the air has been removed. Such a cathode ray tube can be seen in figure. …
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THE ATOM – Its Size (Atomic radius)
Read first – Atoms – Its Symbols Atoms – Atomic Mass What is an atom? As we know, an atom is the smallest building block of everything that exists. It is composed of three sub-atomic particles: the proton, neutron, and electron. Protons and neutrons make up the nucleus of the atom, a dense and positively …
How to write and interpret symbols that depict the atomic number, mass number, and charge of an atom or ion.
SKILLS TO DEVELOP Write and interpret symbols that depict the atomic number, mass number, and charge of an atom or ion. What is an atom? Quiz – Build an Atom / Element / Ion As we know, an atom is the smallest building block of everything that exists. It is composed of three sub-atomic particles: …
Electric Symbols and Electrical Circuits – Introduction and Quiz
Read First – Electric Current Circuit is a continuous path consisting of conducting wires and other resistances between the terminals. Electric circuit is a continuous path made by conducting wires, devices such as resistances, capacitors etc. and voltage sources. A continuous / closed path consisting of conducting wires and other resistances between the terminals of a …
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Defects of Eyes and their Remedies
Read – Human Eye and Colorful World -Eye -Structure Some people can not see clearly objects due to loss of power of accommodation of eye. Such problem may be due to – 1. weakening of ciliary muscles 2. change in size of eyeball 3. Irregularity on the surface of cornea 4. Formation of membrane …
Atmospheric Refraction
Read – Light – Reflection and Refraction / Wonder of Light Part – II Refraction of light rays caused due to variation in density of atmospheric air is called atmospheric refraction. Examples of Refraction in Natural Phenomenon Small – Scale Effects – (a) Mirage – on a very hot summer day in the afternoon, the …
Heredity and Evolution / Mapping our Genes – Variation
[pullquote-right]“The act or process of changing (in genetics) in the characters or traits in an individual from the group to which it belongs or deviation in characters of the offspring from those of its parents is called variation.”[/pullquote-right] Heredity and Evolution – Summary During reproduction, the organism uses its …
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Reproductive Health
How do Organisms Reproduce? / The Life Cycle – Summary Reproductive health is a state of physical, mental and social well being in all matters related to the reproductive system at all stages of life. It also implies that people are able to have a responsible, satisfying and safe sex life. (Defined by WHO) Reproductive …
Control and Coordination in Animals and Plants – Introduction
Read more – Life Processes / Life’s Internal Secrets How do Organisms Reproduce?/ The Life Cycle Heredity and Evolution Why do you quickly remove your fingers on touching a hot object? Who controls and coordinates your heart to relax and contract continuously? What enables you to learn, think, analysis and remember? How can you watch T.V. …
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Life Processes – Nutrition
Read First – Life Pocesses – Introduction Food contains several components known as nutrients. “Nutrients are chemicals- inorganic as well as organic that an organism needs to live and grow”. They are obtained from an organism’s surroundings. There are six major classes of nutrients classified as -proteins, vitamins, water, carbohydrates, dietary fiber, fats and minerals …
Mendeleev’s Periodic Table -Arrangements, Importance, Limitations, FAQ’s
Table of Contents – Mendeleev’s periodic law and Important terminology Arrangements of Mendeleev’s Periodic Table Importance of Mendeleev’s periodic Table Limitations of Mendeleev’s periodic Table Frequently asked questions (FAQ’s) Quiz – Check your understanding Mendeleev’s periodic law and Important terminology – A most important contribution on arrangement of elements after Newland was given by a …
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What is the Versatile Nature of Carbon?
Why are carbon and its compounds so important or special from compounds of all the other more than hundred – odd elements of the periodic table? This is because – (a) The number of compounds that contain carbon is many time greater (due to catenation) than the number of compounds that do not contain carbon. …
Physical Properties of Non-Metals
Read First- Physical Properties of Metals Non-metals Physical state – Non-metals exists in all three physical state. Carbon, sulphur, phos-phorous etc. are solids. Oxygen, nitrogen, chlorine etc. are gases whereas bromine is a liquid. Lustre – Non- metals are non-lustrous substances. Exception – Diamond, graphite (allotropes of carbon) and iodine are lustrous in appearance. Hardness …
Cell : the fundamental unit of life – Summary
Summary – The cell is the fundamental structural and functional unit of all living organisms. Cells were first discovered by Robert Hooke. Structure of cell – Main components – [A] Plasma membrane or Cell membrane and Cell wall (absent in animals) [B] Cytoplasm – composed of matrix and organelles [C] Nucleus You can also enjoy …
Gravitation – Summary
Latest CBSE syllabus topics – Gravitation – Gravitation, universal law of gravitation, force of gravitation of the earth (earth’s gravity), acceleration due to gravity, mass and weight, free fall. Flotation – Thrust and Pressure, Archimedes’ Principle, Buoyancy, Elementary idea of relative density. Latest Maharashtra SSC Board syllabus topics – The Pull of the Earth – …
Work and Energy – Summary
Latest CBSE syllabus topics – Work, Energy and Power – Work done by a force, energy, power. Kinetic and Potential energy, Law of conservation of energy. Latest Maharashtra SSC Board syllabus topics – Work, Energy and Power – Work done by a force, energy, power. Kinetic and Potential energy, Law of conservation of energy. Summary …
THE MUSIC OF SOUND – Summary
Latest CBSE syllabus topics – Sound – Nature of sound and its propagation through different media, speed of sound, range of hearing in humans; ultrasound; reflection of sound; echo and SONAR Structure of the Human Ear. (Auditory aspect). Latest Maharashtra SSC Board syllabus topics – Sound – Nature of sound and its propagation through different …
Basics of Programming
I know that many face problems in coding and coding is not everyone’s cup of tea however one can benefit from the following steps. Also, coding is like maths more you practice better coder you become. So, without any further ado let’s begin. 1. Read the problem carefully. This step is essential while approaching any …
Magnetic Effects of Electric Current -To see the effect of magnetism of bar magnet on iron fillings
Magnets are fancy of children. So many toys use magnets. However magnets have many applications. Magnet attracts iron, nickel and cobalt objects , the unlike poles of magnets attract each other however the like poles of magnets repel each other. Magnets are natural magnets (permanent magnets) and man-made magnets. Earth as magnet – A freely …
ELECTRIC CURRENT – Introduction and Quiz
We use the electric appliances like TV, refrigerator, electric motor, electric torch etc. Electricity is now an essential item in our life and we cannot imagine life without it. Every month we pay for electricity by paying electricity bill. We use many terms for electricity like voltage, current, short circuit , resistance etc. We will …
HUMAN EYE AND COLOURFUL WORLD / WONDERS OF LIGHT PART – I
Eye is the most important sense organ. It is the sense organ through which we can see the world and we can watch the different colours. Eye is similar to camera in the sense that the light enters through cornea and image is formed on a light sensitive screen called retina inside the eye. There …
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How do Organisms Reproduce? / The Life Cycle – Summary
Reproduction – A process by which a living organism is able to produce more of its own kind. It is of two types- asexual reproduction and sexual reproduction. Asexual reproduction – Production of an offspring from body parts other than the reproductive organs. In this, only one organism is involved, no gametes are produced and …
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Heredity and Evolution / Mapping Our Genes -Summary
Summary – Passing down of characters / traits from parents to children is called heredity. Children of same parents differ because they possess different combinations of parental genes. These difference are termed variations. We are all human beings but can be distinguished easily from each other due to variation. Heredity and variation are due to …
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Control and coordination / The Regulators of Life – Summary
• Control is systematic regulation of various activities. Coordination is the orderly execution of the processes. • Homeostasis, in biological terms means that the body is maintaining internal equilibrium to adjust itself internally and physiologically, in response to the external environmental changes. Read more – Life Processes / Life’s Internal Secrets How do Organisms Reproduce?/ The Life …
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Improvement in Food Resources / Quality Food, Quality Life -Summary
Summary – Between 1968-1978, a major improvement occurred in Indian agriculture and animal husbandry. It was veritable revolutions that are known as the Green Revolution and White revolution. On the basis of seasons, crops have been classified as – (a) Kharif crops – These are the crops grown during the rainy season from June to …
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Why Do We Fall Ill / Highway to Health – Summary
Health is a state of complete physical, mental and social well being and not merely the absence of disease. The conditions necessary for good health are – (i) Good physical and social environment. (ii) Good economic conditions. (iii) Social equality and harmony. Thus, for maintaining good health, balanced diet, hygienic surroundings, proper habits, exercise and …
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Diversity in Living Organisms / Life Around You : Summary / Introduction
Taxonomy is the branch of biology for the study of classification of organisms following certain rules or principals. Systematics (systema – order) – The camparative study of organisms on the basis of morphology, anatomy, ecology, physiology, biochemistry etc. is known as systematics. Systematics have three fields (i) Nomenclature (ii) Classification (iii) Taxonomy Classification – grouping …
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Structure of the Atom / Inside the Atom – Summary
Latest CBSE syllabus topics – Structure of atom – Electrons, protons and neutrons ; Isotopes and Isobars. Latest Maharashtra SSC Board syllabus topics – Inside the atom – Historical background ; Rutherford’s scattering experiment ; Distribution of electrons in orbits ; Electronic configuration of elements ; Isotopes and their applications. Summary – E. Goldstein discovered …
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Atoms and Molecules / Counting Matter- Summary, Introduction
Table of content – Summary Introduction Laws of Chemical Combination FAQs
Carbon and its Compounds – Introduction
Symbols – C Atomic number – 6 Atomic mass …
What is Newlands’ Law of Octaves and its significance?
Table of Content What is Newlands’ Law of Octaves? Significance of Newlands’ Law of Octaves Examples Why was this law failed? Frequently Asked Questions – FAQs Quiz Next – MENDELEEV’S PERIODIC TABLE Read First – What are Dobereiner’s Triads? Examples and Limitations. After as Dobereiner’s Traids was ruled out, an English chemist J.A.R. Newlands observed …
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What are Dobereiner’s Triads? Give examples.
J.M. Dobereiner was first to classify elements into some groups having sets of three elements each, called triads. He recognized the relation between atomic mass and their properties.
Physical Properties of Metals
Elements are broadly classified on the basis of their physical and chemical properties- (a) Metals (b) Non-metals Besides metals and non-metals, there is a third group of elements called metalloids which show properties intermediate to metals and non-metals. E.g.- silicon (Si), germanium (Ge), arsenic (As), antimony (Sb) and tellurium (Te). There are very few …
ACID -BASE INDICATORS
On the basis of chemical properties or taste, the compounds were classified into three groups – (a) Acid (b) Base (c) Salt Acid (latin word, acidus = sour) are substances which are sour in taste. e.g. lemon juice, tomatoes, vinegar etc. Bases are bitter in taste. e.g. washing soda, baking soda etc. Salts have taste …
Light – Refraction of Light
Refraction is the bending (change in the direction) of a wave (light or sound). When a light ray passes from one transparent medium to another, it changes speed and bends. Example : Light traveling from air and going into water – half submerged straight stick or pencil into water. The stick appears bent …
Life Processes / Life’s Internal Secrets -Introduction
Living and Non-living – If something is living, it will carry out all the seven functions which are movement, reproduction, sensitivity, nutrition, excretion, respiration and growth. Some non living things may show one or two of the seven characteristics of living things but not all of them. For ex.-car moves, crystals grow in size during …
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Combination Reaction
Combination reactions are those reactions in which two or more reactants (elements and / or compounds) combine to produce a single product. It means, no side product is formed during such reactions. Heat changes may take place during the reaction. Activity – 5 Examples of combination reactions (a) between two elements (b) between two compounds …
Balancing of an Unbalanced Chemical Equation in 5 Easy Steps
Balancing of an unbalanced chemical equation means making the number of atoms of various elements equal in reactants and product in an equation. It is important to note that during balancing a reaction, the formula of a compound (or the subscript of the symbol) must not be changed. For e.g. – H2 + O2 → H2O Here, …
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Balanced and Unbalanced Chemical Equations
Consider the following equations Zn (s) + H2SO4 → Zn SO4 ↓+ H2 (g) (1) Fe + H2O→ Fe3O4 + H2 (2) KClO3 →KCl + O2 …
How to write a Chemical Reaction in Chemical Equation Form?
The description of a chemical reaction in sentences is quite long and time consuming. To make it shorter, a chemical reaction can be written in word equation form. For e.g. – When a magnesium ribbon burns in air / oxygen, it gives magnesium oxide. Activity – 1 Word equation – Magnesium + Oxygen → Magnesium Oxide …
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Characteristics of Chemical Reaction
When a chemical reaction occurs, following observations help us to determine whether a chemical reaction has taken place. (1) Formation of a precipitate (2) Change in colour (3) Evolution of a gas (4) Change in state (5) Change in temperature or evolution / absorption of heat (6) Sound, light may be produced. (7) Change in …
Chemical Reactions and Equations – Introduction
A substance can undergo a change by two ways – (i) Physical changes – This is a change in physical properties such as shape, size, colour and state of a substance. No new substance is formed. A physical change is generally reversible. e.g. Boiling of water, condensation of water vapour, melting of ice, dissolution of …
Pure Substances – (A) Elements
[dropcap]W[/dropcap]When it is said that something is pure, it means that all the constituent particles of that substance are the same in their chemical nature. For ex. N2, O2, H2, Hg, sugar, common salt, water, iron, copper etc. Thus, a pure substance consists of a single type of particles. How can we identify a …
Life Before a Nucleus – Prokaryotic and Eukaryotic Cell
Not all cells have a nucleus. Biology breaks cell types into – (a) Prokaryotic cell (Pro – before + karyon – nucleus) – Those with no defined nucleus. These cells are generally small, primitive and incomplete. These cells do not have a well organized nucleus as nuclear membrane, nucleolus are absent. The genetic material is …
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Nature of Matter (on the basis of their Chemical Properties)
Read First – Can Matter change its States? States of Matter What is Matter? What is its Characteristics? [dropcap]Matter[/dropcap] is everything around us which is made up of tiny particles. In the previous posts, we have learnt classification of matter into solid, liquid and gas, on the basis of their physical properties. In the following post, …
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Condensation (Gas changes into Liquid )
Read First – What is Matter? What is its Characteristics? States of Matter Can Matter change its State? Evaporation (Liquid changes into Gas) [dropcap]Why[/dropcap] do we see water droplets on the outer surface of a glass containing icecold water? do we find dew drops, especially in the early morning on the leaves? The water vapor …
Evaporation (Liquid changes into Gas)
Read First – Can Matter change its States? States of Matter What is Matter? What is its Characteristics? [dropcap]I[/dropcap]In liquids, there are always a few particles with a lot of energy and some with very low energy. A small fraction of particles at the surface, having higher kinetic energy, is able to break away from …
Why do we fall ill / Highway to Health – Summary
Summary – Health is a state of complete physical, mental and social well being and not merely the absence of disease. The conditions necessary for good health are – (i) Good physical and social environment. (ii) Good economic conditions. (iii) Social equality and harmony. Thus, for maintaining good health, balanced diet, hygienic surroundings, proper habits, …
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Tissues / Life – Simple and Complex – Summary
Summary – A tissue is a group of cells with a common origin, structure and function. The study of tissues is called histology. The Plant Tissues – The plant tissues are mainly of two types – 1. Meristematic (Gk. meristos : dividing) 2. Permanent (non-dividing) Meristematic Tissue – (a) Apical Meristem Location – Root tip …
Can Matter change its State?
Read First – What is Matter? What is its Characteristics? States of Matter [dropcap]W[/dropcap]e know, water exists in all three states – • Solid as ice • Liquid as water • Gas as water vapor. Now questions arise – (1) How do changes from one state to other state take place? (2) What happens to …
Equations of Motion by Graphical Method
When an object moves along a straight line with uniform acceleration, it is possible to relate its velocity, acceleration during motion and the distance covered by it in a certain time interval by a set of equations of motion. There are three such equations. The equations were summarized by Issac Newton. These are – Here, …
Outer Membrane of The Cell – Cell wall
The cell wall is exclusively present in plant cells including bacteria. Position – It is present external to the plasma membrane and is formed of dead substances (mainly cellulose) secreted by the protoplasm of the cell. Characteristics – 1. It is a rigid, freely permeable, non-living part of the cell. 2. Plasmolysis – …
What are the States of Matter? – Properties and FAQs
Matter around us exists mainly in three states – solid, liquid gas This can be understood with the help of three forms of water – ice, water and water vapor . Read First – What is Matter? What is its Characteristics? Table of Content – Matter – Introduction Recommended Video The Solid State The Liquid …
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Graphical representation of motion
[dropcap]G[/dropcap]Graphs have two axis on which two quantities can be represented and relation of the two quantities can drawn. We know that runs scored by the cricket team with overs are shown a bar graph on the television. The graphs are representation of events which can be used for comparisons etc. In mathematics, the line …
Outer membrane of Cell – Cell membrane / Plasma membrane
Outer membrane of Cell [A] Cell membrane / Plasma membrane Position – This is the outer covering of the animal and plant cells which encloses the mass of cytoplasm and gives separate identity to the cell. Characteristics – (i) Selectively permeable so allow only selected substances to pass in (water, salt, oxygen) and out (carbon …
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What is Matter? What are the Characteristics of Matter?
Matter is everything around you which is made up of particles. It has mass and occupies space. Mass is a physical quantity which expresses the amount of stuff in an object. The space inside the container that is occupied by matter is its volume. Early Indian philosophers classified matter in the form of five basic elements – the …
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What is Uniform and Non-uniform Motion? Give Examples.
Suppose an object moves 10 m in first 10 seconds, 10 m in second 10 seconds, 10 m in third 10seconds, then the motion of the object is uniform motion . Whereas, if the object moves different distances in same time intervals, the motion of the object is non-uniform. Suppose there are two objects A …
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Morphology of Cells – Size, Shape and Structure
The shape, size and structure of cells are often related to the specific function they perform. Read First – Cell – The Fundamental unit of Life – Summary Cell – Introduction Cell Shape The shape of a cell may be variable (e.g. W.B.C. or leucocyte ; Amoeba have changing shapes) or fixed and peculiar for …
What is Chemistry? What are the main branches? What is its Importance and Scope?
[dropcap]W[/dropcap]When you hear the word ‘chemistry,’ there are certain images that come to mind – a colorful lab, colored liquids, different smells – good or bad (Ugh!!), glass wares, test tubes, the periodic table, molecules, maybe even some cool explosions (BOOM!), magic tricks in a movie…..But chemistry is so much more than these things… in fact, …
What is Chemistry? What are the main branches? What is its Importance and Scope? Read More »
Motion / Moving Objects
Introduction We see so many moving objects everyday like moving buses, trains, running cricketers, flying aeroplanes, moving ships etc. When we are sitting in a moving train, the things outside appears to be moving. When the train stops at platform, the things outside move when they are in motion. But if the another train is …
Cell : The Fundamental Unit of Life
Introduction If something is living, it will carry out all the seven functions which are [highlight]movement, reproduction, sensitivity, nutrition, excretion, respiration and growth[/highlight]. Some non living things may show one or two of the seven characteristics of living things but not all of them. For ex.-car moves, crystals grow in size during crystallization process. [pullquote-right]“Thus, the …
A CHEMICAL REACTION IS CHARACTERIZED BY EVOLUTION OF A GAS AND BY EVOLVING HEAT (EXOTHERMIC REACTION).
Take a few zinc granules in a conical flask. Add dilute hydrochloric acid (HCl) or sulphuric acid (H2SO4) in the conical flask. (a) What do you observe ? (b) Touch the conical flask and observe any change in its temperature ? Objective – A chemical reaction characterized by evolution of a gas and by evolving heat …
COMBINATION REACTION
Slowly add water in a small amount of calcium oxide or quick lime containing in a conical flask. Touch the beaker. Do you feel any change in temperature ? Objective – Combination reaction with heat change. Inference – Calcium oxide (CaO) reacts vigorously with water and form a single product, calcium hydroxide (slaked lime). CaO(s) + H2O …
TO STUDY A THERMAL DECOMPOSITION REACTION.
Take a small amount of ferrous sulphate crystals in a dry test tube. (a) Note the colour of the ferrous sulphate crystals. Heat the test tube over the flame of a burner or spirit lamp. (b) Observe the colour of the crystals after heating. Objective – To study a thermal decomposition reaction. Inference – (a) Before …
IN A CHEMICAL REACTION, ORIGINAL SUBSTANCE LOSES ITS NATURE AND IDENTITY
Objective– To understand a chemical reaction. Procedure – Take a magnesium ribbon. Clean it by rubbing with sand paper. (a) Why should magnesium ribbon be cleaned before burning in air ? Hold it with a pair of tongs. Burn it in the flame of a burner. Collect the ash so formed in a watch glass. Precaution …
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Common Chemistry Lab apparatus
Some commonly used chemistry lab apparatus are shown in the video.
PURE SUBSTANCES – ELEMENTS AND COMPOUNDS
Pure Substances – The constituents of mixture can not be separated by simple physical methods. (i) Elements – Substance that cannot be decomposed into two or more different substances by a simple chemical process. e.g. hydrogen, oxygen (ii) Compounds – Substance of definite composition that can be decomposed into two or more different substances by a simple …
VALENCY – COMBINING CAPACITY OR COMBINING POWER
Every element has a definite capacity to combine with other elements. The combining capacity of an element is called its valency.” In normal course, hydrogen has 1, oxygen has 2, nitrogen has 3 and carbon has 4 valency. This will depend upon the nature of the element. Read First – Ions – Cations and …
List of Polyatomic Ions and Charges
Simple ions – The ions which are formed from single atom carrying a positive or negative charge are called simple ions or mono-atomic ions. Example – Na+, Cl–, O-2, Al+3, N-3(nitride), Mg+2, Ca+2, Cu+2, Fe+2etc. Polyatomic ions -Polyatomic ions or compound ions are molecules formed from groups of atoms bonded together that carry a positive …
IONS – Anions and Cations
Atoms are neutral; they contain the same number of protons (positive particles) and electrons (negative particles). When the numbers of these subatomic particles are not equal, the atom is electrically charged and is called an ion i.e. ions are electrically charged atoms with extra electrons or missing electrons. It means ions are formed when atoms lose or gain …
Molecules of Elements and Compounds
How do atoms exist? Atoms of elements exist in nature either in uncombined form or in combined form. (a) The atoms of some elements called the noble-gas elements (helium, neon, argon, krypton, xenon) are normally found in nature as isolated (single) atoms as they are chemically unreactive. (b) The atoms of most elements are chemically …
THE ATOM – ITS ATOMIC MASS
Read first – The Atom – Its Size Atom – Its symbols Atomic mass of an element (1) The mass of an atom is related to the number of protons, electrons, and neutrons it has. Atom of an element is extremely small and therefore it is not easy to weigh it. Even that, it is …
My Corner – Is it becoming more difficult to forgive than ever before?
Is it becoming more difficult to forgive than ever before? What is forgiveness ? A beautiful reply – “It is the fragrance the flowers give when they are crushed”. When we get angry, we don’t want to settle the dispute, when we are hurt, we don’t want to forgive, we want revenge. What we …
My Corner – Is it becoming more difficult to forgive than ever before? Read More »
Matter and Its Characteristics
Matter is everything around you which is made up of particles. It has mass and occupies space. Mass is a physical quantity which expresses the amount of stuff in an object. The space inside the container that is occupied by matter is its volume. Early Indian philosophers classified matter in the form of five basic elements – the …
What is Matter?
Matter can be anything which occupy space and have mass. • On the basis of Physical state, matter can be divided into – (a) Solid (b) Liquid (c) Gas • On the basis of Macroscopic or bulk level, matter can be divided into – (a) Mixture – which are further divided into – (i) Homogeneous mixture (ii) Heterogeneous …
What are the postulates of Dalton’s Atomic Theory of Matter – Drawbacks, Importance and FAQs
Table of content – Reasons for Dalton’s atomic theory Dalton’s Atomic Theory Drawbacks of Dalton’s theory Importance of Dalton’s theory Frequently asked questions Important to learn – Law of Conservation of Mass Law of Definite Proportions / Constant Composition Mole Concept – Importance and formulas John Dalton FRS (6 September 1766 – 27 July 1844) John …
How to solve Problems based on Law of Definite Proportions / Constant Composition
Read first – What is Matter? What is its Characteristics? States of Matter Law of Conservation of Mass Problems based on Law of Conservation of Mass Law of Definite Proportions / Constant Composition Mole Concept – Importance and formulas Problem 1 : One mole of V2O5 contains 5 moles of oxygen atoms, as it is clear from …
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What is Law of Definite Proportions / Constant Composition?
Table of Content – What is law of definite proportions / constant composition ? Examples Importance of law of definite proportions Limitations of law of definite proportions Problems based on law of definite proportions/ constant composition Frequently asked Questions What is Matter? What is its Characteristics? States of Matter Law of Conservation of Mass Problems …
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Problems based on Law of Conservation of Mass
Problem : 1 4 grams of hydrogen reacts with some oxygen to make 36 grams of water. Figure out how much oxygen must have been used by applying the law of conservation of mass? Solution: Word equation – Hydrogen + Oxygen → water Masses of each substance given – …
What is Law of Conservation of Mass? – Examples and Problems
Table of Content – What is Law of Conservation of Mass? Examples Experimental verification of Law of conservation of mass Problems based on Law of Conservation of Mass Frequently Asked Questions – FAQs Test your understanding – Quiz Read more – What is matter? What is its Characteristics? States of matter Mole Concept – Importance …
What is Law of Conservation of Mass? – Examples and Problems Read More »
Change of States of Matter – [B] Effect of change of Pressure
Read First –Can Matter change its States?States of MatterWhat is Matter? What is its Characteristics? [B] Effect of change of Pressure – By increasing pressure, particles of matter can be brought close together. When we apply pressure on a gas enclosed in a cylinder, it starts compressing and converts into liquid. Thus, by applying pressure …
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Can Matter change its State? Effect of Temperature and Pressure
We know, water exists in all three states – • Solid as ice • Liquid as water • Gas as water vapour. Now questions arise – (1) How do changes from one state to other state take place? (2) What happens to the particles of matter during the change of states? (3) What happens inside …
Can Matter change its State? Effect of Temperature and Pressure Read More »
Change in States of Matter – [A] Effect of change of Temperature
Table of Contents – [A] Effect of change of Temperature NEXT – Change in States of Matter – [B] Effect of change of Pressure Matter does not always remain in the same state. It can be made to change its state either by changing in temperature or pressure. First you read – Can Matter change …
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Cell – The basic unit of Life
Cell – The Basic Unit of Life From the Video, you will learn – Definition Important Discoveries Cell Theory Concept Map
THE ENGLISH ALPHABETIC CODE – WHY ARE THEY COMPLICATED CODE AND THE MAIN REASON FOR THE READING AND WRITING PROBLEMS?
The main reason for the reading and writing problems, which are so commonly found in English-speaking countries, is the complex nature of written English. English has a very complicated alphabetic code, so complicated in fact, that it is often referred to as having an ‘opaque’ code. Alphabetic languages, such as Hindi, German, Spanish, Italian and Finnish, …
OXYGEN SUPPORTS COMBUSTION
Procedure 1. Fix a candle in the middle of the small trough. 2. Fill the trough about half with water. 3. Place a long glass tumbler in the inverted position upon the candle. 4. Mark the level of water in the glass tumbler either by rubber band or with marker. 5. Remove the glass tumbler …
IMPORTANT POINTS ON MATTER
To convert the temperature in celsius scale to kelvin scale, add 273 to it. 0°C = 0 + 273 = 273K 5°C = 5 + 273 = 278K 100°C = 100 + 273 = 373K The temperature in kelvin scale is represented by symbol K and not °K. High melting point of a solid shows …
A CHEMICAL REACTION IS CHARACTERIZED BY FORMATION OF A PRECIPITATE.
When a chemical reaction occurs, following observations help us to determine whether a chemical reaction has taken place. (1) Formation of a precipitate (2) Change in colour (3) Evolution of a gas (4) Change in state (5) Change in temperature or evolution / absorption of heat (6) Sound, light may be produced. (7) Change in …
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