Blog Tag SCIENCE

Q. Write notes on— (a) Adam’s apple. (b) Secondary sexual characters. (c) Sex determination in the unborn baby.

Q. Write notes on— (a) Adam’s apple. (b) Secondary sexual characters. (c) Sex determination in the unborn baby. Ans (a) Adam’s apple: The protruding part of the throat is called Adam’s apple. It is the enlarged voice box or larynx which gets enlarged and visible from outside in boys at the onset of puberty. This makes . . .

Cloning

Q. Write a note on cloning. Ans: Cloning is the process of making a genetically identical organism through nonsexual means It has been used for many years to produce plants (even growing a plant from a cutting is a type of cloning).  Animal cloning has been the subject of scientific experiments for years, but garnered little attention until the . . .

Migration

Migration Some animals move great distance at certain time of the year. This mass movement of animals from one place to another is known as migration. Animals migrate to escape harsh weather, to search for food and to reach their breeding grounds. Some birds like storks, Siberian crane and mallard ducks from other countries visit India every winter. . . .

Types of joints

Types of joints A joint is a meeting point of two bones held together by strong tissue called ligaments. There are several joints in our body. All joints except those in skull are movable. The bones in the skull are interlocked, making the joints immovable. The movable joints The bones at the joints move smoothly because of a fluid which act . . .

Miniature circuit breaker (MCB)

A miniature circuit breaker is an automatically operated electric switch that protects an electric circuit during an overload or short circuit. They can be reset (manually or automatically) to restore normal operation, whereas in circuits with fuses, the fuse needs to be replaced after a single use. . . .

Terms related with Electricity

Current: The flow of electricity is called current. Voltage: The voltage applied across a device causes current to flow through it. The greater the voltage across a device, the greater is the current through it. Volts: Voltage is measured in volts. Battery: A group of connected cells is call battery. Electric circuit: A path along which an e . . .

Resistance

The electrical resistance of a piece of material is a measure of the hindrance it creates to the flow of electric current. The lower the resistance the greater is the current. . . .

Heat produces depends on resistance

The higher the resistance the greater the current, the greater is the heat produced. For example: Connect a bulb to a battery. After some time, touch the wires and the bulb. You find that the bulb is much warmer than the wires because the resistance of the filament of the bulb is higher than that of the wires. . . .

Combustion and Flame

· Combustion: The process of burning a substance in the presence of air (oxygen) and undergoes a chemical reaction to produce heat and light. · The substances which burn in air are called combustible. · Oxygen (in air) is essential for combustion. · During the process of combustion, heat and light are given out. . . .

Chemical Effects of Electric Current

Materials which allow electric current to pass through them are good conductors of electricity and which does not allow electric current to pass through them are good conductors of electricity We should not experiment or play with the electrical appliances Some liquids are good conductor of electricity and some are bad conductors of electricity . . .

Teeth and their types

Teeth and their types A tooth is made up of two parts – Crown and Root. Crown is the visible part of tooth. Root is part of tooth inside the gum. The place where crown meets the tooth is called neck. Layers of tooth The outer layer of tooth is called enamel. It is the hardest substance in our body. Below the enamel is dentine. It suppo . . .

Case study- Gulf war oil spill

Case study- Gulf war oil spill In August 2010, two cargo ships collided near the Mumbai coast. It caused a major oil spill and almost around 800 tonnes of oil spilled into the Arabian sea. Some of the containers had toxic pesticides. This caused a major threat to marine ecology of the area and the coast, affecting several fish species and the growing . . .

Why do tides occur

Why do tides occur Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun and the rotation of the Earth. The moons gravity is very weak, it has a noticeable effect on the earth. It pulls the water of the seas and oceans of the earth, ca . . .

Process of obtaining silk from the silk moth.

For obtaining silk, moths are reared and their cocoons are collected to get silk threads. The cocoons are boiled to separate out silk fibres from cocoon. Threads obtain from the cocoon spun into silk threads, which are woven into silk cloth by weavers. The process of taking out threads from the cocoon for use as silk is called reeling the silk. Seric . . .

Heat produced depends on current

The greater the current, the greater is the heat produced. For example: Connect the terminals of a cell with a wire for a few seconds. The wire will get very hot. The wire has a low resistance, which allows a large current to flow in the circuit. This produces a large amount of heat, which makes the wire hot. Connect a bulb to the cell. The r . . .

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