Page 86 - SST Class 05

thermal energy : electricity produced from burning coal or wood.
residue : what remains at the end of a process.
lightning : bright flashes of light in the sky during a thunderstorm.
hydroelectricity : electricity produced from flowing water.
nuclear energy : electricity produced from splitting of atoms.
conventional sources of energy : electricity produced from coal, mineral oil etc.
non-conventional sources of energy : electricity produced from water, wind, sunlight etc.

Facts

• We need different sources of energy to run our machines.
• Coal, mineral oil and electricity are conventional sources of energy.
• Non-conventional or alternative sources of energy like wind energy, solar energy, tidal energy and
gobar gas energy are clean sources of energy.
• Conventional sources of energy cannot continue infinitely.
• Electricity is produced from coal, water, mineral oil, wind, sunlight etc.
• There is need to balance modern progress with environment cleanliness and health.

XERCISE

A. Tick (3) the right option :
1. ____________ sources of energy cause environmental pollution.
(a) conventional (b) non-conventional (c) alternate
2. Petroleum was first discovered in ____________ .
(a) Netherlands (b) America (c) Germany
3. Benjamin Franklin conducted experiments on ____________ .
(a) diesel (b) coal (c) electricity
4. ____________ is produced from running water.
(a) hydroelectricity (b) thermal energy (c) nuclear energy
B. Answer the questions briefly :
1. What do we need energy for?
2. How is petrol different from diesel?
3. How did Benjamin Franklin find that lightning was electricity?

4. How is thermal electricity different from hydroelectricity?
5. What do you understand by clean sources of energy?

Energy and You

v Energy has made many machines automatic. As people are growing greatly dependent on
machines and are unwilling to do much physical work, ill-health has become very common.
The use of energy has also produced several threats to health and environment. How do you
suggest to balance the use of machines and health? Write briefly in your notebook.

86 Contemporary Social Science-5