Page 2 - Sources of Energy

The muscular energy for carrying out physical work, electrical energy
for running various appliances, chemical energy for cooking food or
running a vehicle all come from some source. We need to know how do
we select the source needed for obtaining the energy in its usable form.

Activity 14.2
Activity 14.2
Activity 14.2
Activity 14.2
Activity 14.2
 Consider the various options we have when we choose a fuel for
cooking our food.
 What are the criteria you would consider when trying to categorise
something as a good fuel?
 Would your choice be different if you lived
(a) in a forest?
(b) in a remote mountain village or small island?
(c) in New Delhi?
(d) lived five centuries ago?
 How are the factors different in each case?

After going through the two activities above, we can see that the
particular source of energy, or fuel, we select for performing some work
depends on many different factors. For example, while selecting a fuel,
we would ask ourselves the following questions.
(i) How much heat does it release on burning?
(ii) Does it produce a lot of smoke?
(iii) Is it easily available?
Can you think of three more relevant questions to ask about a fuel?
Given the range of fuels we have today, what are the factors which
would limit our choices when it comes to a particular task like cooking
our food? Would the fuel selected also depend on the work to be done?
For example, would we choose one fuel for cooking and another for
heating the room in winter?
We could then say that a good source of energy would be one
 which would do a large amount of work per unit volume or mass,
 be easily accessible,
 be easy to store and transport, and
 perhaps most importantly, be economical.

Q U E S T I O N S
?

1. What is a good source of energy?
2. What is a good fuel?

3. If you could use any source of energy for heating your food, which one
would you use and why?

Sources of Energy 243