Students and Teachers Forum
Honey is the good for human beings as it contains most of the nutrients such as vitamins, proteins, carbohydrates. Some of the importance of honey are listed below: 1. Honey is rich in vitamins and functions as anti-oxidants. 2. Honey contains .....
The economic importance of silk are as follows: 1. Silk is used in making clothes and curtains. 2. Silk is used with other natural and synthetic fibres to achieve new effects in fabrics. 3. Silk being a valuable fibre, it helps in improvement of the .....
Silk thread is extracted from the cocoon of the silkworms. Cocoon is the covering of pupa which is made up of silk threads. To extract the silk thread, the cocoons are kept in hot water or placed in a hot oven (air) to destroy the sticky substance .....
Sericulture is the rearing of silkworm for the commercial for the commercial production of silk fibre. Sericulture is the important and excellent mode for employment generation in the agricultural country like Nepal. It is suitable for small-scale .....
The three advantages of honey bees are: 1. Honey bees produce honey, which is a good source of protein. 2. Honey bees help in pollination while collecting nectars and increases the crop productivity. 3. Bee wax is a natural wax that is produced in .....
Worker bees Drones 1. These are sterile female. 1. These are fertile male. 2. These are smallest bees. 2. These are .....
Following are the precautions that should be taken during sericulture. i. Clean and dry mulberry leaves are fed to larvae. ii. For obtaining commercial silk, the cocoons are treated with hot water or placed in a hot .....
The reasons for killing the pupae inside the cocoon during extraction of the silk thread are: i. To get long and uncut silk thread. ii. To make unwinding easy without .....
Larva of silk moth being a voracious feeder, it requires mulberry leaves for the survival. During winter mulberry leaves are not available as the mulberry is a deciduous plant. To prevent the larva from hatching, the eggs are kept at the temperature .....
Silk moth Honeybee 1. Silkmoth does not live in a colony. 1. Honeybee lives in a colony. 2. Silkmoth is the source of silk fibre. 2. Honeybees are the source of .....
Silk is extracted from the cocoon by keeping the cocoons in boiling water or a hot oven to destroy the glue or sticky substances of the cocoon and to make unwinding .....
Natural silk Artificial silk
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Honey bees collect nectar (sugar-rich liquid produced by plants) and pollen to rear their young's. While doing so their hairy bodies trap pollen and transfer carry it between flowers and serve as vital .....
Pupa Cocoon 1. It is living organism. 1. It is non-living thing. 2. It lies inside the cocoon. 2. It covers .....
Honey bees are known for producing and storing honey as well as building impressive large hives using wax secreted by the workers in a particular colony. The honey bee's lifecycle goes through four basic stages. They are an egg, larva, pupa and .....
A silkworm is a useful insect as it produces a high-quality silk fibre. Silk fibre is used to produce silk clothes, shawls, etc. There are two types of silk moths commonly reared in Nepal. They are Eri and Seri. The cultivation of silkworm is known .....
Polythene is a polymer made from ethene (CH2=CH2). It is one of the most commonly used materials. It is a soft plastic, which softens on heating. It is used for making bottles, buckets, and pipes, as covering for electrical wires and cables and as .....
The advantages of fertilizer are: 1. It promotes fast growth and development of plants. 2. It helps to increase the yield of crops. 3. It helps to resist disease. The disadvantages of fertilizers are: 1. Low growth of plants 2. Reduce disease .....
A glass is an amorphous transparent homogenous mixture of silicates of alkali metals and silicates of alkaline earth .....
Soap is made by heating oil with sodium hydroxide. The oil and sodium hydroxide solution are fed into an enclosed reaction vessel under high pressure and heated at high temperature. At this temperature, the reaction is completed in a few minutes. .....
Limestone and clay are mixed in definite proportion and ground to a fine powdery state. This dry powder is used as such or mixed with water to form a paste and heated in a rotary kiln (a type of furnace). It is slowly made to pass through the kiln .....
Polyesters are another category of polymers. One important member of this family is dacron which is also known as terylene. It is prepared by reaction between terephthalic acid and ethylene glycol. It is crease resistant, durable and is not damaged .....
Nylon is a polymer of small monomeric units called amide (-CO-NH-) i.e. it is a polyamide. It is prepared by reaction of adipic acid and hexamethylenediamine. Terylene is crease resistant, durable and is not damaged by insects like moths and by .....
Borosilicate glass is sodium aluminium borosilicate and can withstand rapid heating and cooling. It is used for making kitchen and laboratory ware. Flint glass is used for making lenses, prisms, spectacles, etc. Coloured glass is made by adding .....
The glass produced as given above is called sodalime glass or soft glass. It is used for manufacture of bottles ordinary crockery, ordinary laboratory glass apparatus like soda glass test tubes .....
Antibiotics are medicines which are used to kill bacteria, fungi and moulds. The first antibiotic discovered was penicillin which is very effective for pneumonia, bronchitis, sore throat, etc. Ampicillin is a slight modification of penicillin. It .....
Soap is the sodium or potassium salts of higher fatty acids e.g. sodium stearate. When some fats or oil is heated with sodium solution, it splits into the sodium salt of the higher fatty acid (i.e. soap) and glycerol.
The glass which is made by heating of the mixture of potassium carbonate, calcium carbonate, and silica is called hard glass. It is used for making different types of laboratory equipment like a beaker, hard glass-test-tubes, etc. and electric bulbs .....
The common name for borosilicate glass is Pyrex glass. Borosilicate glass is used to make laboratory equipments because a. It is resistant to chemicals. b. It can withstand high .....
The industrial chemical formed by silica, lead oxide and potassium carbonate is lead crystal .....
Environmentalists request to avoid the use of plastic because plastic is non-degradable substance which produces poisonous gas and pollutes the .....
PVC is not used to cover the handle of pressure cooker but Bakelite is used because PVC becomes soft on heating while Bakelite becomes hard on heating and is bad conductor of .....
The differences between natural and artificial fibres are as follows: Artificial fibres are of two types: Natural fibres Artificial fibres 1. Fibres, which are naturally found, are called natural fibres. 1. The manmade fibres .....
Humans are more responsible to degrade the environment than other living beings on earth. Vehicles, big factories and large amount of chemicals that we use cause environmental degradation. To control environmental degradation, following steps can be .....
The environment pollution caused by various chemicals like insecticides, chemical fertilizers, synthetic cleanser and other industrial chemicals is called chemical pollution. The causes of environmental pollution are: 1. The use of .....
Nitrogen is important to plants because it promotes fast growth and development of plants. It helps to form a large amount of protein and .....
The chemical fertilizer containing all plants nutrients ie. nitrogen, phosphorous and potassium is called NPK fertilizer. NPK fertilizer is also called the complete .....
Ammonium phosphate(NH4)3PO4 and Calcium super .....
Urea (NH2CONH2) and Ammonium .....
Potassium Nitrate (KNO3) and Potassium .....
The difference between soap and detergent is tabulated below: Soap Detergent 1. It is a sodium or potassium salt of fatty acid. 1. It is a synthetic petrochemical obtained from hydrocarbon. 2. It is not suitable for .....
The poisonous chemicals which are manmade and used to control or destroy harmful insects are called insecticides. The advantages of insecticides are: 1. They kill or destroy harmful insects quickly. 2. They help to control several diseases by .....
a. Dichloro diphenyl trichloroethane b. Benzene Hexachloride c. Polyvinyl .....
Detergents are called the soap less soap because they have cleansing property in water like soap but their chemical nature is different from .....
Detergents are the sodium salts of a long chain benzene sulphonic acid or long chain alkyl benzene sulphate which have more cleansing property in .....
Soap is the sodium salt of long chain fatty acids that have cleansing property in water. The raw materials used for manufacturing soap are: Animals fat or vegetable oil, sodium hydroxide, stearic acid, palmitic acid, oleic acid .....
The advantages of synthetic fibers are: 1. They are light in weight and strong. 2. They melt at low temperature. 3. They are used as fishing net, carpets .....
Ceramics is the science of pottery which may be defined as objects made from a special type of clay, hydrated aluminium silicate, feldspar and silicates. The hard, brittle and porous article is heated and coated with a tin oxide or lead oxide .....
The difference between the hard and soft glass is tabulated below: Soft Glass Hard Glass 1. It is produced by heating sodium carbonate and calcium carbonate with silica. 1. It is obtained by heating potassium carbonate and .....