Energy transformations

We know that energy can not be created or destroyed but it can change from one form into another. We see examples of such transformations every day.

We will now try some exercises.

All energy on Earth has originated from the Sun. We change the many forms of energy into electrical energy to drive our modern cities and to maintain our standard of living. There are many different types of power stations, two of which are coal fired and hydro-electric power plants. Although both coal-fired and hydro-electric power plants use generators to produce electricity it is the method each uses to spin the turbines driving the generators that is different.


Consider the animation above, showing the process of photosynthesis. This is a process that requires energy in order to proceed. It is therefore said to be endothermic.

1) Where does the energy to drive the process of photosynthesis come from?

2) What type of energy is solar energy converted into?

3) What is the advantage of chemical energy over solar energy?

4) How is energy passed on from organism to organism in a food chain?

5) The chemical word equation for photosynthesis is given below
water + carbon dioxide + energy => sugar + oxygen.

The sugar is used by the plants as food and as a structural material to from wood.
We burn would to release its energy and the chemical equation for this reaction is given below.
sugar + oxygen.=> water + carbon dioxide + energy

i) Where does the heat energy given off when burning wood come from ?

ii) What is the ultimate source of the heat energy given off when burning wood ?