September 24, 2021
Communicable diseases spread from one person to another by the entry of pathogens (disease causing organisms). Pathogens enter our body through various means, and then multiply there. They can be transferred from one person to another by direct or indirect contact.
September 23, 2021
Acid rain is caused when nitrogen oxides, SO2 and particulate matter in the atmosphere react with H2O to produce acids. Acid rain is harmful to the environment. It affects life in water and on land. The fish cannot survive in acidic water below pH 4.5. It can also damage trees in the forests.
September 22, 2021
Pollutants like sulphur dioxide which is released while burning sulphur containing fuel and particulate matter like soot present in stagnant air masses, get modified in sunlight and form a sheet called photochemical smog.
September 21, 2021
Greenhouse is referred to as a chamber where plants are grown in a closed warm environment as compared to the outside temperature. This is normally practised in cold region of the hills. The solar radiations bringing heat (in the form of infra-red rays from the sun) are trapped inside the chamber.
September 20, 2021
The ozone layer present in the earth's atmosphere prevents the entry of sun's harmful ultraviolet (UV) radiations reaching the Earth's surface. Industrial use of chemicals called chlorofluorocarbons (CFCs) in refrigeration, air conditioning, cleaning solvents, fire extinguishers and aerosols (spray cans of perfumes, insecticides, medicines) damage the ozone layer.
September 19, 2021
Anything which is unwanted or useless is termed as waste. The waste generated from various sources can be categorized into two types: Biodegradable waste and Non-biodegradable waste.
September 18, 2021
Any undesirable change in the environment due to human activity is pollution. Each activity, human or industrial, discharges some unwanted substances in the environment. The presence of unwanted substances in a concentration which can have an adverse effect on organisms and environment is called pollution.
September 17, 2021
Cutting of the natural forest cover is called deforestation. Forests are being cut for various purposes, such as for growing crops and grazing cattle, meeting the demand of wood and paper.
September 16, 2021
Landslide is often accompanied by cloudburst. A cloudburst is an extreme amount of precipitation, sometimes with hailstorms and thunderstorms. It occurs for few minutes and can create flood conditions which often results in landslides.
September 15, 2021
In monsoon, massive landslides occur in the hilly regions leading to blockage of roads. A landslide is the gravitational movement of a mass of rock, earth or debris down a slope. It occurs when a hilly slope becomes unstable.
September 13, 2021
From prehistoric times, forests and fire have remained inseparable. The temperate world’s forest ecosystem has been re-generated and rejuvenated with active help of forest fires.
September 12, 2021
Earthquake is a common phenomenon. It is the shaking, rolling or sudden shock of the earth’s surface. The intensity of earthquake is related to the amount of energy released when rocks give way to the forces within the earth. It is measured with the help of an instrument known as seismograph. The intensity of an earthquake is measured on the Richter scale.
September 09, 2021
Environmental problems arise both due to natural processes and human activities. These problems adversely affect human and other forms of life.
September 08, 2021
All living organisms are interdependent, otherwise it would be difficult to live together in a population.
September 07, 2021
Adaptations are special features that allow a plant or animal to live in a particular place or habitat.
September 06, 2021
There is a constant need of nutrients by the biotic community for their survival and they take these from the environment. Nutrients in the form of oxygen, carbon dioxide, nitrogen, phosphorus, sulphur or water exists in a definite amount in the environment.
September 05, 2021
Food provides energy and thus in a food chain, energy is passed from one link to another. This energy flow is unidirectional - the energy which is transferred from one trophic level to the next does not come back.
September 04, 2021
A simple food chain basically consists of producers, herbivores and carnivores. For example, small fish feeds on phytoplanktons which in turn is being eaten by a bigger fish. This constitutes the food chain.
September 03, 2021
Biotic community refers to populations of various kinds of organisms living together and sharing the same habitat. An ecosystem houses several biotic communities which interact with each other.
September 02, 2021
All living and non-living things that occur naturally on the 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.
September 01, 2021
Carboxylic acids contain the carboxyl (-COOH) functional group. Their general formula is R-COOH. Vinegar which is also called acetic acid has the formula CH3COOH.