Questions Section A

 

Answers Questions Section B

Questions Section B

 

Activity Zone- Energy -Wise Tips

Answer : Another way to save energy

Using Energy Wisely

        Most of the energy that we use today requires the use of non-renewable energy resources.We need to use energy wisely to make sure we have enough energy in the future,save cost,avoid wastage and reduce pollution.
        Our energy resources will not last forever.We must learn not to waste energy so that there is enough for eneryone.What can you do to save energy?

This simple checklist will help to improve the energy efficiency at home and cut down electric cost.

Exercises: Can you gives another example to save energy?

 

Advantages of Renewable Energy

Renewable energy is better than non-renewable energy because:

 

The impacts of the use of renewable energy resources are much smaller and more localized.They also help in the conservation of fossil resources for future generations.

Type of Renewable and Non-renewable Energy

1. In the 1830s, a British astronomer John Herschel used a solar collector box to cook food during an expedition to Africa. Now, people are trying to  use the sun’s energy for many other purposes. Besides its continuous supply and advantages, the  use of solar energy is increasing. Solar energy is also becoming more and more important because energy from petrol will disappear soon.

2.  Biomass energy or bioenergy  (energy from organic matter) has been used for thousands of years, ever since people started burning wood  to cook or to keep warm .And today, wood is still our largest biomass energy resource.However, many other sources of  biomass can now be used, including plants,residues from agriculture or forestry and the organic component of municipal and industrial wastes. Even the fumes of landfills can be used as a biomass energy source.The use of biomass can also help increase profits for the agricultural industry.

3. Hydroelectric  power is the biggest source of renewable energy,providing 14% of the world's electricity.Fast flowing water released from dams in mountainous area can turn water turbines to produce electricity.In most cases, water is stored behind a dam in a reservoir.Water pressure forces the water onto the blades of a turbine.Rotation of the generator  represents the kinetic energy which is finally transformed into electric energy  will be supplied for public usage. Ocean or tidal waves can also be used to generate electricity.

4. Coal  is a fossil fuel formed over millions of years from plants.It is a hard,black coloured rock-like substance made of carbon, hydrogen, oxygen, nitrogen and sulphur. Coal is mainly burned in power stations to produces electricity.When  coal is burned,it produces a large amount of carbon dioxide, one of the gases responsible for the greenhouse effect.

5. Petroleum is an oily, flammable, liquid solution of yellowish green or black colour, which occurs naturally in earth.It is formed from decomposed plants and animals a long time ago. When distilled, gasoline, kerosene, paraffin, fuel oil, benzene, bitumen and  others.These products are used in houses for heating and cooking and in factories as a source of heat energy.They are also  used to provide fuel for transport and in power stations. However, their uses,especially petrol and diesel,produce a large amount carbon dioxide.They also produce other poisonous gases that may harm the environment and people's health.

6. Natural gas is formed from the remaining plants,animals and microorganisms that lived millions of year ago.Natural gas  a colourless and odourless in its pure form. When  burned,it  given off a great deal of energy.Unlike other fossil fuels,natural gas emits lower levels of harmful by-products into the air.Natural gas has many applications,commercially,in your home,in industry and even in the transportation sector.

Type of Renewable and Non-renewable Energy

Renewable or Non-renewable Energy Resources

What are Renewable or Non-renewable Energy Resources?

1.Energy resources are divided into  two groups: ·        Renewable energy ·        Non-renewable energy

2.Renewable energy can be replenished when    used up.

3. Non-renewable energy  cannot be replenished     when used up.

4. Renewable energy resources include solar      energy, wind energy, geothermal energy from     inside the Earth, biomass from plants and        hydropower from water stores in reservoirs     and oceans in the form of wave.

5. We get most of our energy from      non-renewable energy resources, which      include crude oil, natural gas and coal.     They are called fossil fuels because     they are formed over millions of years     from the remains of dead plants and animals     by the action of heat from the Earth’s core      and pressure from the rock and soil. Fossil      fuels are continually produced by decaying     plant and animal matter, but the rate of     their production is extremely slow, very      much slower than the rate at which we      use them.

Renewable Energy

Non-renewable Energy

Kinetic Energy and Potential Energy

 

Kinetic Energy Kinetic energy is related to motion of waves, electrons, atoms, molecules , substances and objects.

Potential Energy Potential  energy is the energy that is stored and related to the position of something.

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Answer ( Check Your Understanding)-Transformation Of Energy

A Burning Candle		chemical  energy   →   light  energy  + heat  energy
lamp		electrical energy    →     light energy + heat energy
rice cooker	electrical energy → heat energy
Computer	electrical energy→ light energy + sound energy
Hair  dryer	electrical energy→   heat energy + sound energy
Calculator	solar  energy →   electrical energy →  light energy
Solar powered signal light	solar energy → electrical energy →  light energy