NCERT Solutions for Class 5 EVS Chapter 12

The substances that exists naturally on the earth and can be used by the people in different ways are called natural resources. Example- Sunlight, air. Water, plants, animals, soil, minerals, fossil fuel etc.

The two types of different of natural resources are-
a) Renewable Resources
b) Non- Renewable Resources

Petroleum is a very important fuel which is found in its crude form. Petroleum is a naturally occurring liquid which is found beneath the earth’s surface and can be refined into fuel. Petroleum is a fossil fuel as it has been created by the decomposition of organic matter over millions of years and is used to make various by products like petrol, diesel, LPG, Jet Fuel.

The advantages of using petroleum products are as follows:
• They are very important sources of energy as they originate from living things, once plants and animals
• They help us to run our vehicles
• They help us to cook our food
• They heat our homes
• They provide us with electricity

The disadvantages of using petroleum products are-
• They are non-renewable resources
• Burning of these fuels emits carbon dioxide which leads to global warming
• It also produces sulphur dioxide which contributes to acid rain
• Transporting fuels from mines or well can cause pollution and lead to serious accidents

Some fuel saving techniques which we should follow at home are:
• Use pressure cookers or covered utensils and vessels for cooking or heating as they consume less heat.
• Try to use solar cookers or heaters for cooking or heating water as solar energy is a renewable resource.
• Switch off the fans and lights when not in use so as to save electricity produces by thermal power plant that use coal.

The problems faced due to increasing number of vehicles on the road are:
• Overcrowding or jams on the roads
• Air and noise pollution caused due to burning of fuel, running engines, honking of vehicles,
• Pollution leading to lung disorders and hearing problems
• More usage of fuels will increase the prices and make them too high
• Overuse can result in finishing of the resources.

If the fuels get finished then,
• Life of the people will come to a standstill as we use these resources in our daily life
• Commuting to far off places would become very difficult
• We will have to look for alternative sources as they will not be available.

CNG is preferred over petrol and diesel to run vehicles as it has less carbon content whereas petrol and diesel majorly have more carbon along with lesser number of other gases. So, CNG produces less smoke on burning and thus causes less pollution.
Compressed Natural Gas (CNG) is thus a clean fuel as it does not produce any smoke and gives very high energy. It is often called an eco-friendly fuel. CNG is used as a fuel in auto rickshaws, cars and buses to control pollution.

Burning of damp wood and cow dung cake while cooking in villages leads to bad cough as it produces a lot of smoke which contains harmful gases / When these gases are inhaled then it causes persistent cough and lung related diseases like Bronchitis, Asthma. It can also lead to a deadly disease called cancer.

An oil refinery is an industrial process plant where crude oil is transformed into more useful products such as petrol, diesel, kerosene, CNG and jet fuel.

Petrol is pumped out along a pipe from the tank and mixed with air in the carburetor, from which the engine sucks in the mixture. In the fuel-injection system which is used on some engines, the petrol and air are mixed in the inlet in many ways. A fuel pump draws the petrol out of the tank through a pipe to the carburetor

Coal is a valuable natural resource. It is a kind of rock formed from the remains of plants which decay into compost and get converted into coal by the heat and pressure over millions of years. Some iron and steel making and other industrial processes burn coal.

Petroleum products are obtained when the petroleum refineries change the crude oil into petroleum products so that they can be used as fuels for transportation, heating, paving roads, and generating electricity and as feed stocks for making chemicals. By refining, the crude oil breaks down into its various components, which are then converted into new products.

Majority of people use cow dung uple, wood etc as fuel to:
• Fulfill their need of fuel and overcome the shortage of daily fuel requirements
• to make food especially the rural population still uses the older methods such as cow dung, wood and twigs to ignite fire and cook
• moreover, they are cheap and locally as well as easily available.
• cook food, keep themselves warm, for heating water and for lighting.

Mining is the process in which things are dug out of the ground. Any material that cannot be grown must be mined. Mining things from the ground is also called extraction. Mining can include extraction of metals and minerals, like coal, diamond, gold, silver, platinum, copper, tin and iron.

Minerals are substances that are formed naturally in the Earth. Rocks are made of minerals. Minerals are usually solid, inorganic, have a crystal structure, and are formed naturally by geological processes.

The problems which are faced due to speeding vehicles are-
• accidents happen due to speeding vehicles.
• Damage of human life.
• It causes more pollution.
• It can cause traffic jams.

Petrol and diesel will not last forever because:
• Both of them are fossil fuels which take millions of years to be formed.
• They are non-renewable resources.
• These resources are not going to be available again when once used.
• Thus, these resources must be used judiciously and wisely as they may not be available in future due to their too much use in present.

Solar panels are the devices that are used to absorb the sun’s rays and convert them into electricity or heat. A solar panel is actually a collection of solar cells, which can be used to generate electricity. They are thus, the devices that convert light into electricity. They are called “solar” panels because they work on the most powerful source of light, the Sun. Lots of small solar cells spread over a large area can work together to provide enough power.

From petroleum or oil that we get the following products:
• kerosene
• diesel
• petrol
• engine oil
• fuel for aircrafts
• L.P.G. (cooking gas)
• Wax
• Coal tar
• grease.

Petroleum is useful as it is:
• used as a fuel and plays an important role in land, sea and air transportation.
• Refined and used in the production of various petrochemicals like gasoline, lubricating oil, printing ink etc.
• used for power generation.
• used for dry cleaning purposes.
• used for making plastic and paints
• used for running machines
• Used for lighting

The prices of petrol and diesel keep going up because the production of both of them is limited while the demand and consumption of both is increasing day by day. Moreover, usage of more vehicles and dependence of people for commuting from one place to another has increased the number of vehicles on road and thus it has resulted in more vehicles and lesser fuel availability.

We need to use the resources wisely and judiciously because resources like oil, minerals, and soil take hundreds or thousands and even millions of years to be made. These are called non-renewable resources. It is very important that we use renewable and non-renewable resources wisely. If a resource is used and thrown away, gradually the resource will become scarce. There will be a shortage of the resources and human life will some to a standstill as no resources will be left for our future generations. Some resources are not going to last forever so we should use them without wasting them.

Synthetic fuels are those fuels which very expensive to process and thus cannot be manufactured on a large scale. They are made from biomass, coal, natural gas, oil and shale.

Diesel is cheaper than petrol because its extraction processes are simpler than that of petrol. Diesel engines are more efficient than petrol engines of the same power, resulting in lower fuel consumption.

Coal is formed in the following ways-
1. Millions of years ago, the earth was covered with thick forests growing in swamps.
2. Due to earthquakes and volcanic eruptions many forests got buried under the surface
3. Due to the high temperature and pressure inside the earth, the remains of the plants turned into coal

A coal mine is a place where plenty of coal is found is called a coal mine.

Coal is the fuel which is used in steam engine. It is burned to produce heat which boils water in the boiler to produce steam which moves the piston and this is how it works.

Fossil fuels are those fuels which cause pollution when burnt. They give out carbon and carbon-di-oxide and other gases into the atmosphere, which results in Global warming. They are not ecofriendly resources and thus are not good for the environment.

Alternate sources of energy means those energy source which are other than fossil fuels and are being used in place of the fossil fuels. Some alternate sources of energy are solar energy, wind energy and energy from flowing water.

It is important to use alternate sources of energy such as solar energy, wind energy and energy from flowing water as –
• they are renewable resources
• they do not get exhausted and can be replenished easily
• their use does not cause pollution and they are thus environment friendly.