A jackscrew is a type of jack that is operated by turning a leadscrew. In the form of a screw jack it is commonly used to lift moderately heavy weights, such as vehicles. More commonly it is used as an adjustable support for heavy loads, such as .....

You can see spiral threads on the surface of screw. The distance between successive threads of the screw is calle the pitch of .....

The roads in hilly region are bent because bent roads are the form of inclined plane. They having longer distance. This makes us walk easier by magnifying .....

Nepal is located in Asia basically in the south Asian region. It lies in Tropical Monsoon Climatic region. The Tropical Monsoon Climatic region is located between 5o to 30o latitude in both hemisphere. This region has distinct seasons; .....

You know simple machine are those machine which makes our work easier, faster and safer. There are so many simple machines that we use daily. Scissor is the one which we often use. We use nail cutter, stapler,shapner, knife etc. These are all .....

As you know, MA is the ratio of load to the effort. (MA = L/E) When effort is greater than the load, the value of MA is less than .....

There are 3 classes of levers.

1. A Class 1 lever has the fulcrum placed between the effort and load. The movement of the load is in the opposite direction of the movement of the effort. This is the most common lever configuration.

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A lever is a rigid bar, straight or curved, which is free to turn about a fulcrum. You might have played seesaw during your child hood. It is an example of lever. On the basis of position of load, fulcrum and effort, lever are classified as 1. .....

Mainly, there are six types of simple machines.  They are - 1.lever, 2.pulley, 3.wheel and axle, 4.inclined plane, 5.screw and 6. .....

Definitely, natural resources should be consumed within the limit because they are limited. It is the fact that human needs and desires are boundless. One after another the human needs and desires grow. Human being depends on the natural .....

This is because, the sun simply outputs more power than our eye is designed to handle, and exposing our eye to that kind of power can damage the retina. And in a nutshell, solar eclipses are dangerous because the sun can come out from behind the .....

Earth Earth, the third planet from the sun and the largest terrestrial planet, is the only planet known to have living beings and the only one with liquid water on its surface. The atmosphere made of mostly nitrogen, oxygen and carbon dioxide is .....

An eclipse occurs when one object gets in between you and another object and blocks your view. From Earth, we routinely experience two kinds of eclipses: an eclipse of the Moon and an eclipse of the Sun. There are two types of eclipse we .....

The outer planets are – Jupiter, Saturn, Uranus, and Neptune. The outer planets are also called the Jovian planets or gas giants. Like the inner planets, the outer planets have similar characteristics to one another. The outer planets are so .....

You can see the asteroid belt in the above figure. The plantes enclosed by the asteroid belt are inner planets. They are mercury, venus, earth and mars. Mercury and venus have no satellite. Earth have one satellite .You know moon. Mars have 2 .....

A planet , meaning “wandering star” is an astronomical object orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its .....

There are some elements like arsenic, antimony and germanium which shows both the character of metal and non-metal. They are metalloids. The characteristics of metalloids are 1. They are poor conductor of heat and electricity. 2. They possess .....

 There are other properties of non-metals as well. Like: The window pane in your house is made up of glass. This glass is a .....

Hunting reserve: Hunting reserves are the places where controlled hunting of some species is allowed. The Dhorpatan Hunting Reserve is the only hunting reserve in Nepal. It was established in 1987 A.D. It covers an area of .....

Government of Nepal has established different conservation areas in order to conserve the nature and wildlife. It has also established one hunting reserve (Dhorpatan Hunting reserve)  for the controlled hunting of some permitted .....

Deforestation can have a negative impact on the environment. The most dramatic impact is a loss of habitat for millions of species. Eighty percent of Earth’s land animals and plants live in forest and many cannot survive the .....

You know industrialization is very important for development. But, these are so many  effects of industrialization  too on the environment: They are :

The effects of unmanaged urbanization are: 1. Increase in environmental pollution 2. Poor health and spread of disease 3. Water and sanitation problems 4. Unemployment 5. Overcrowding 6. Traffic congestion .....

Some of the effects of deforestation are: 1. It causes the loss of animal and plant species due to the loss of their habitat. 2. It allows a greater amount of greenhouse gases to be released into the atmosphere 2. It affects the water cycle in .....

We can prevent soil erosion by applying following methods: 1. Planting more number of trees and shrubs (afforestation). 2. Adding mulch (decaying compost)or rocks to the topsoil.      This will weigh down the soil and .....

A landslide is a destructive natural disaster. Therefore, it should also be controlled. Some of the preventive measure are  1. Destruction of forest and forest products should be discouraged. 2. Planatation of trees should be encouraged in .....

Deforestation simply means the destruction of .....

You know the hunting reserves are also the wildlife reserves.  But, the difference is, some species are allowed for hunting under limited contions in the hunting .....

You might have learnt about National park. A national park is a park in use for consevation purposes. As national park are made to protect flora and fauna, that live inside them or land itself. There are many national park in .....

The process of transporting of the upper crust of the earth by rainwater,rivers and rivulets is known as soil erosion. It destroys the fertility of land. Soil erosion has been the critical problem in Nepal. Soil erosion occurs if there is heavy .....

Look at the following figure. The appararent depth of the pond is less than the real depth. So, the fish appears to be nearer than it actually is. Hence, the fisherman on the bank must aim at the spot  below the apparent image of a fish to .....

When we do not dispose waste properly, or when we throw chemicals onto the soil in the form of pesticides, insecticides and fertilizers, the earth surfaces gets contaminated or polluted. This destruction or contamination of earth's land .....

Air pollution means mixing of unwanted gases in the air. These unwanted gases may comes from factories, industries or may be at home. Gas from old vehicles often cause air pollution. Dust particles also get mixed with air and cause air .....

You know all over the world, people consume resources directly or indirectly. You use natural resources like trees, coal ,water etc for so many purpose. We use them for construction of road, bulidings ,trains, automobiles etc.  Think about .....

Some examples of perpetual resources include solar energy, tidal energy, and wind .....

Look at the following diagram. The diagram shows a simple electromagnetic spectrum. You may know that the wavelength of visible rays is about 10-6 m and 10-7 m. In the diagram, the wave with just long wavelength and beside the visible is the .....

When human beings misuse the land, land pollution occurs.  A common example is excessive use of pesticides for growing .....

Nature friendly development work is simply defined as the development activity which do not harm the .....

Look around your surroundings. You can see different things that affect our life. Like soil, air, tree, plants, animals, land etc. All these physical surroundings on Earth are called .....

Can you compare your bodily structure now and few years ago. There is change in your body, isn't it? There is change in your behaviours. Your life style, policy of talk, etc. have been changed. Don't you think that it is the development .....

The process by which food is converted into substances that can be absorbed and assimilated by a living organism. In most animals it is accomplished in the digestive tract by the mechanical and enzymatic breakdown of foods into simpler chemical .....

You may know that demagnetization is the property by which a maget loses its magnetic power. Magnets can be demagnetized by following ways  1. If a magnet is dropped frequently. 2. If a magnet is hammered. 3. If a magnet is heated. 4. If .....

There are so many uses of magnet in our daily life. Some of them are  1.They are used in factories for lifting heavy masses of iron and steel. 2. They are used in scientific devices such as electric motors, dynamics, telephones, television .....

There are two types of artificial magnets: Temporary and Permanent.  Temporary magnets are magnets that aren't always magnetic, but their magnetism can be turned on when required. Examples: Electromagnet and paper clip. Permanent .....

You know artificial magnet are made by human and they can be found in various shape and size. The advantage of artificial magnets are 1. It has very high attracting power. 2. It can be easily made but natural magnet cannot and they are rare .....

Okay take a piece of iron near the magnet. It attracts the iron. Take that iron  away from it gradually. At some point the magnet will not attract iron. Thus, a region when the magnet attract shows its attracting property is known as .....

Okay, bring wood, plastic near to the magnet. They would not get attracted. Thus, those substance which are not attracted by a magnet are known as non- magnetic substance. Example plastic, wood,copper, paper .....

When we bring iron near to the magnet, iron attracts magnet. Thus, iron is magnetic substances. Those substance which are attracted by the magnet are called magnetic substance. Example iron, steel, cobalt .....

You might have seen magnet in your science lab or at your home. They are artificial magnet. The magnet which are made from the artificial sustance are called artificial magnet. They can be of various shape, like in above .....

The magnet which is obtained from the nature is known as natural magnet. Loadstone is an example of natural magnet. Its attracting power is very .....