Energy, Power & Climate Change Topic 8 Energy, Power & Climate Change

Types of Energy

Types of Energy

Energy Flow diagrams We can write energy flow diagrams to show the energy changes that occur in a given situation. Name the energy changes that occur when a car engages its brakes

Energy Flow diagrams Notice the size differences of the terms Kinetic heat sound

Another Example Sketch an Energy Flow Diagram of a rocket launch

Rocket Launch Chemical Kinetic Gravitational heat heat sound

Energy degradation! In any process that involves energy transformations, the energy that is transferred to the surroundings (thermal energy) is no longer available to perform useful work.

Energy transfer (change) A lamp turns electrical energy into heat and light energy

Sankey Diagram A Sankey diagram helps to show how much light and heat energy is produced

Sankey Diagram The thickness of each arrow is drawn to scale to show the amount of energy

Sankey Diagram Notice that the total amount of energy before is equal to the total amount of energy after (conservation of energy)

Sankey Diagrams Take out two pieces of paper On the first piece of paper, create three examples of energy changes in 3 words or less Pass it to another group Write the corresponding energy flow diagram (including heat losses) that you receive on the second piece of paper

Wrap up Read the energy transfer process from your Sankey Diagram We will guess what the situation you were describing

Efficiency Although the total energy out is the same, not all of it is useful.

Efficiency Efficiency = useful energy output total energy input Efficiency is defined as Efficiency = useful energy output total energy input

Example Efficiency = 75 = 0.15 = 15% 500

Energy efficient light bulb Efficiency = 75 = 75% 100

Energy efficient light bulb Efficiency = 75 = 75% 100 That’s much better!

More complex examples

Another Sankey

This too shall pass Name all the energy transformations in this video