Energy

Energy

Energy

• Is the ability to do work

• Units = joules (J)

What is work?

Chemical Energy

• is found in the chemical bonds in• food• fuel and• batteries

Kinetic Energy

• Moving energy

Potential Energy

• Energy due to position or condition

• Water behind a dam or at top of waterfall• Wound up spring e.g. wind up clock

Electrical Energy

• Energy in moving charges

Sound

• Is a form of energy caused by vibrations

• Measured in decibels

• Needs a medium to travel through

• Echo is reflected sound

Electrical Energy

• Energy in moving charges

Heat

• Is a form of energy• Joules (J)• Not the same as temperature

Insulator

•Does not allow heat or electricity through

•(opposite to conductor)

•E.g Air trapped in double glazed windows (heat) •E.g. water under wet suit (heat)

Nuclear Energy

• Energy found in the nucleus of an atom• (released in atomic bomb or nuclear power station)

• Cheap • Dangerous wastes –

– radioactive- causes cancer or cures it (in right dose)

Energy Conversions

• Convert means • To change

For each energy conversionWrite down The energy that goes in ( or is in it)And The energy that “comes out”

Energy Conversions

• Toaster • IN =

• Electrical energy • OUT =

• Heat energy (and a little light)

• BATTERY• IN =

• CHEMICAL energy • OUT =

• ELECTRICAL energy

Energy Conversions

• Hair Dryer • IN =

• Electrical energy • OUT =

• Heat energy (and sound and kinetic)

• Leaf • IN =

• solar energy • OUT =

• Chemical energy in food

Renewable energy

• will never run out

• solar, wind, hydroelectric, wave, biomass, geothermal

• do not add to greenhouse effect

Hydro-electricity

• Electric current generated by the potential and kinetic energy of water

• (Dams are wider at bottom due to more pressure deeper down)

• Energy change = potential (behind dam) kinetic (flowing water) electrical ( in turbine)

Tidal Energy

• Renewable energy from the movement of the tides.

Others• Geothermal• Heat energy from under the surface of the Earth • Solar energy• solar panels - expensive & clean• WIND energy• expensive & clean / danger to birds• BIOMASS • Grow trees that re-grow quickly • Use timber to burn for heat

Non renewable energy

• Will run out sooner or later

• Coal oil turf gas petrol

Fossil Fuel

• Coal oil gas turf• Made from dead plants and animal remains• Make CO2 and H2O when burned

• Non - renewableLimewater - milky

Cobalt chloride – bluepink

Joule

• Unit of energy (J) • Unit of work (J) • In food kilojoules are used (kJ)

All in one• Energy is the ability to do work• Kinetic moving energy• Potential energy due to position (high) or condition (stretched or wound up)• Chemical (food fuel and batteries) energy stored in the bonds of chemicals• Solar energy from the sun (light)• Sound energy due to vibrations• Magnetic energy from magnets attracting and repelling• Convert means to change• Conserve means to keep• Law of Conservation of energy

• energy cannot be created or destroyed only changed from one form to another• Battery changes chemical energy to electrical energy• Bulb changes electrical energy to light energy• Electrical energy from moving charges (electrons)• Nuclear energy stored in the nucleus (centre) of an atom• Joule (J) the unit of energy

• The End