General Science

Transformation of Energy

Energy can exist in many different forms. Energy can be changed from one form to another. But it cannot be created or destroyed. It just gets transformed into another form. Eventually, most of it ends up as heat, but it is so spread out that it cannot be detected or used.

Read more ...

Hydrogen Energy

Hydrogen could be a very environmentally friendly source of energy in the future. In the long-term, hydrogen is likely to reduce dependence on conventional sources of energy such as petrol, diesel and coal. In addition to it, the use of hydrogen as source of energy will help in reducing the emission of greenhouse gases and other pollutants.

Read more ...

Energy from Biomass

The biomass is organic material made from plants and animals. It includes garbage, industrial waste, crop residue, manure, wood, sewage and dead parts of living objects. Like all other sources of energy, it also contains stored energy from the sun. Therefore, biomass is also a very good source of energy.

Read more ...

Ocean Energy

The ocean is also a powerful source of renewable energy. The energy of the ocean can be harnessed in three basic ways: using wave power, using tidal power, and using ocean water temperature variations.

Read more ...

Geothermal Energy

Geothermal energy is another alternative source of energy. Geothermal energy is obtained from the internal heat of the earth. It is one of the oldest types of natural sources of heat. It dates back to Roman times, when the heat from the earth was used instead of fire, to heat rooms and warm water for baths.

Read more ...

Hydroelectric Energy

Like wind energy, the flowing water and water stored in huge dams is also a very important source of energy which is known as hydroelectric energy. But, overdevelopment and unrestricted harnessing of water power can have a devastating effect on the local environment and habitation areas.

Read more ...

Wind Energy

Wind power is another alternative energy source that could be used without producing by-products that are harmful to nature. Like solar power, harnessing the wind is highly dependent on weather and location. However, it is one of the oldest and cleanest forms of energy and the most developed of the renewable energy sources.

Read more ...

Solar Energy

The sun has been providing heat and light for billions of years and it is expected that it will continue to do so for billions of years to come. All plants get their energy from the sun and all animals get their energy mainly from the plants. Therefore, the sun is a source of energy for animals.

Read more ...

Renewable Energy Sources

The fossil fuels such as coal, oil and natural gas meet most of the energy needs of the world today. But what will happen when the reserves of these non-renewable sources of energy get completely exhausted? We also need to pay attention to the damaging effects of fossil fuels on the environment.

Read more ...

Nuclear Energy: Energy from the Atom

The atoms of a few elements such as radium and uranium act as natural source of energy. Atoms of these elements spontaneously undergo changes in which the nucleus of the atom disintegrates.

Read more ...

Non Renewable Energy Sources

Petrol and diesel extracted from crude oil are commonly used to run different kinds of vehicles, such as cars, buses, tractors, trucks, trains, and aeroplanes. Similarly, kerosene and natural gas are used as fuels in lamps and stoves. Crude oil, coal and natural gas occur in limited and exhaustible quantities. They cannot be regenerated in a short period of time or used again and again. Hence, they are called non-renewable sources of energy.

Read more ...

Natural Gas

Natural gas is another major source of the energy. Oil and gas fields have been found everywhere on the planet except on the continent of Antarctica. These fields always contain some gas, but this natural gas (methane) does not take nearly as long to form.

Read more ...

Coal

Coal is formed in a way similar to the other fossil fuels, though it goes through a different process called coalification. Coal is made of decomposed plant matter in conditions of high temperature and pressure, though it takes a relatively shorter amount of time to form.

Read more ...

Introduction to Energy

We take food for survival and growth of our body. Vehicles like motorcycles, tractors, buses, trucks, ships and aeroplanes require fuel for their running. Even for cooking food we require fuel. What is important which we get from the food or from the fuel? It is the energy.

Read more ...

Buoyancy and Archimedes' Principle

A mug filled with water appears to be heavier when it is lifted from bottom of the bucket to above the surface of water than the mug within the water in the bucket.

Read more ...

Mass and Weight

Mass of a body is the quantity of matter contained in the body. Mass of an object is constant and does not change from place to place. It remains the same whether the object is on earth, on moon or anywhere in outer space.

Read more ...

Motion of an Object Under Gravity

The g is constant near the surface of earth. Therefore, all the equations for uniformly accelerated motion of bodies become valid when acceleration a is replaced by g.

Read more ...

Acceleration Due to Gravity

The speed of a falling stone increases continuously. The stone is accelerated due to force of attraction between the stone and the earth. This acceleration is called the acceleration due to gravity.

Read more ...

Newton's Law of Gravitation

Newton expressed the law of gravitation in the language of mathematics.

Read more ...

Force of Gravitation

A force is required to change the state of rest or of motion of a body. All objects when dropped from a height fall towards the earth. Why do objects fall towards the earth?

Read more ...

Environmental Problems

Environmental problems arise both due to natural processes and human activities. These problems adversely affect human and other forms of life.

Read more ...

Natural Environment

All living and non-living things that occur naturally on earth constitute the natural environment. All living organisms are dependent on the environment for their survival. Their life is regulated by the environment and in turn they influence the environment.

Read more ...

Water

Water is the most important substance needed for survival of living beings. Living beings cannot live long without water. Water is available in plenty on earth. More than three-fourth of the earth’s surface is covered with water in the form of seas, rivers and lakes. It is also found inside the earth’s crust Most of the water that we get from the wells comes from this source.

Read more ...

Air

Air is a mixture of gases and is one of the main abiotic components of the environment. Air is an extremely important natural resource, as living organisms breathe in air. Air is found everywhere. Air in motion is called wind. It is also present in water and soil.

Read more ...

Health and Hygiene

According to the World Health Organization (WHO), health is a State of complete physical, mental and social well being and not merely the absence of disease. It means proper functioning of the body and the mind.

Read more ...

Food and Nutrition

The sources of food are broadly classified into two groups - plants and animals. Humans consume everything from fruits, flowers and even the stem of some plants. Leaves and stem like lettuce, celery, etc; roots of some plants like carrots, beetroot, etc. and seeds like wheat, rice, etc. All food come from plants as even the animals depend on plants. Hence, the source of all food in this world are plants, directly or indirectly.

Read more ...

Heredity

The passing down of similar characters generation after generation is termed heredity. Heredity is controlled by genes. Differences in gene combinations lead to variations or differences even among members of the same family. The science of heredity and variation is termed Genetics.

Read more ...

Reproduction

Reproduction is defined as the biological process by which organisms give rise to their own kind. Reproduction may occur in two ways:

Read more ...

Nervous System: Control and Coordination

The nervous system and the endocrine system ensure that the body works in a controlled and coordinated manner. The nervous system includes the brain, spinal cord, sense organs and nerves while the endocrine system operates through certain chemicals called hormones which are produced by specialized glands and are secreted directly into the blood. The nervous system works with the endocrine system to communicate, integrate and coordinate the functions of various organs and systems in our body.

Read more ...

Digestion, Transportation, Respiration & Excretion

The activities by which living organisms take in food, derive energy, remove waste from their body and respond to changes in the environment are called life processes.

Read more ...

Cells and Tissues

The invention of microscope helped in the discovery of the cells. Robert Hooke discovered the cell in 1665. Soon a cell theory was formulated.

Read more ...

Living Organisms

Biodiversity is the enormous variety of organisms is termed biodiversity (bios means life and diversity means variety). There is diversity in size among organisms and in complexity. For example, bacteria are simple single celled organisms and humans are made of a trillion cells and are highly complex.

Read more ...

Materials: Metals and Non-Metals

Elements can be broadly divided into two categories: metals and non-metals. They differ both in physical and chemical properties.

Read more ...

Physics Scientific Reasons

An object immersed in water appears lighter. Why?

When an object is immersed in water it experiences an upthrust exerted by water in upward direction. Hence, it appears light in weight.

Read more ...

Sound and Communication

Sound is a result of vibration. The vibration is produced by a source, travels in the medium as a wave and is ultimately sensed through the ear - drum.

Read more ...

Light

Reflection of Light

Some objects such as sun, stars, burning candles, lamp, etc. which emit light by their own are called luminous objects. Some other objects may bounce back a part of the light falling on them from any luminous object. This bouncing back of light after falling on any surface is called reflection of light.

Read more ...

Heat

Temperature is a measure of the degree of hotness of an object. Thermometer is a device used for measuring temperatures. Clinical thermometer is used to measure our body temperature. The range of this thermometer is from 35°C to 42°C. For other purposes, we use the laboratory thermometers. The range of these thermometers is usually from -10°C to 110°C. The normal temperature of the human body is 37°C.

Read more ...

Magnetism

When electric current passes through current carrying conductor or coil then a magnetic field is produced around it. Opposite to this is if a continuous change in magnetic field is produced then electric current can be produced.

Read more ...

Electricity

A plastic comb when brought near a piece of paper does not pick up small pieces of a paper. But if you comb your dry hair and bring the comb close to a small piece of paper, you will notice that the bits of paper are attracted towards the comb. This happens because the comb gets charged or electrified when you comb your dry hair.

Read more ...

Properties of Solids and Fluids

Fluid Pressure is the force acting normally on unit area of a surface due to a fluid is called the fluid pressure.

Read more ...

Gravitation

While Newton was sitting under an apple tree, an apple fell on him. The fall of the apple set Newton thinking, why did the apple fall down? If some force is acting on the apple then it must be in accelerated motion.

Read more ...

Motion

Motion is a continuous change in the position of the object with respect to the observer.

Read more ...

Thrust and Pressure

Some bodies like table, desk, bucket full of water press the floor with a force equal to their own weight. The weight is the force acting vertically downwards. As the surface of the floor can be taken as horizontal, therefore, the force with which each body presses the floor is directed perpendicular to the surface of the floor.

Read more ...

Force of Friction

A ball rolling along the ground stops after moving through some distance. Similarly, a moving car begins to slow down the instant its engine is switched off and finally it stops.

Read more ...

Conservation of Momentum

Law of conservation of momentum is a very important law of science. According to this law, if two or more objects collide with each other, their total momentum remains conserved before and after the collision provided there is no external force acting on them.

Read more ...

Newton's Third Law of Motion

Newton in his third law of motion stated a relation between action and reaction. According to this law, to every action there is an equal and opposite reaction.

Read more ...

Newton’s Second Law of Motion

According to Newton’s first law of motion the application of an unbalanced force brings a change in the velocity of an object. Thus, the force can produce a change of momentum. Newton’s second law of motion establishes a relationship between force and change in momentum.

Read more ...

Momentum

The force required to stop a moving body depends upon its mass. Suppose two balls of same mass are moving with different velocities. Which ball will need more force to stop? The faster moving ball require more force to stop it. Thus, the force required to stop a body also depends upon its velocity.

Read more ...

Newton's First Law of Motion

An object offer resistance to change in its state of motion. This was studied by Newton in detail and he presented his findings in the form of three fundamental laws that govern the motion of objects.

Read more ...

Inertia

The inertia is the tendency of objects to stay at rest or to keep moving with the same velocity.

Read more ...