Sankey diagram
Sankey diagrams summarise all the The different ways in which energy can be transferred from one store to another includes heating, by waves, electric current or by a force moving an object. taking place in a process.
The thicker the line or arrow, the greater the amount of energy involved.
This Sankey diagram for an electric A thin, high resistance wire that gets hot and glows when a current flows through it causing it to emit heat and light. Filaments are used in some types of bulb and electrical heaters. lamp shows that most of the electrical energy is transferred as heat energy rather than light energy.
The Principle of Conservation of Energy
In the above Sankey diagram, note that 100 J of electrical energy is supplied to the lamp.
Of this, 10 J is transferred to the surroundings as useful light energy.
The remainder, 90 J (100 J 鈥 10 J) is transferred to the surroundings as wasted heat energy.
The energy transfer to light energy is the useful transfer.
The rest is 鈥榳asted鈥.
It is eventually transferred to the surroundings, making them warmer.
This 鈥榳asted鈥 energy eventually becomes so spread out that it becomes very difficult to do anything useful with it.