Energy

Today we will:

1. Define energy, work and the principle of conservation of energy2. List different forms of energy transfer3. Name units related to energy

Key words: transform, transfer, conservation

Starter activity

•Ability to do work or cause change•Produces Warmth•Produces Light•Produces Sound•Produces Movement•Produces Growth•Powers Technology

What is energy?

What is work?

Work is what something does whenever it transfers energy

from one form to another.

So a light bulb does work as it transfers energy from electrical energy to light and heat energy.

Describe work in your own words, write the answer on a mini-whiteboard

yes , because your body is transferring energy from chemical potential to heat and kinetic (in your heart).

Are you doing work when you sit still doing nothing?

What is work?

What is work? 0:43

Work = force x distance moved in the direction of the force

The Work Equation

𝑊=𝐹×𝑑 (Joules)

Energy is needed for us to do work. Energy is measured in Joules, J or kilojoules, kJ.

The work equation questionsEasy Medium Hard

Write the equation to calculate work done.

What is the work done if we apply a 1.2N force and we move 4 m in the direction of force?

Thinking about energy transfers:When you rub your hands together what are the energy transfers?

The Principle of Conservation of Energy

This fundamental piece of science says that you cannot destroy or create energy.

(If you find a way - keep it quiet until you have taken out a patent - and you'll be a rich person!).

People often say that you use up energy. Do you agree with this statement?

When you use energy, you are simply converting it into other forms of energy - so it is still out there it is just no longer in the nice, useful form that you had it in a moment before.

The Principle of Conservation of Energy

Energy enables work to be done. People and machines need energy supplied to do

work. Energy exists in many different forms.

Review of your progresslist different forms of energy

FORMS OF ENERGYPotential energy

oElastic (Rubber band, Spring)oGravitational (Weight)oChemical (fuel, food)oNuclear (atoms)

Heat/Thermal (fire, sun, candles, heater)Kinetic (running person, moving car)Electrical (electricity)Electromagnetic (fan, calling bell)Sound (speakers, headphones)

The story of kinetic and potential energy

Potential or kinetic?

There are many different ways for energy to change its form.

We use Diagrams to show energy transfers:

http://www.eon-uk.com/EnergyExperience/708.htm

Now, lets do some practical work

You have 30 minutes to perform you investigation into energy changes and write observations in your notebooks.

recap

Homework

1. What is useful and wasted energy?

2. How to calculate efficiency and power?

Next lesson:

We will learn about work done, power, efficiencyand perform calculations

Please, bring calculators