Physipics Review Fames

TWO: ENERGY

NOTE: These FREE Frames are samples of a much larger, and growing, collection. They are not presented here in an unbroken sequence. The complete set, with both FREE and NOT FREE Frames provides explanation without gaps. 

thermal energy transfers I: gaining and losing energy

E1: Thermal energy transfers I

Syllabus / specification points:

• The Sun acts as a huge store of energy, emitting energy to space

The Earth has a lower temperature than the Sun, and gains energy from it

• Energy transfers from a mug of hot energy to the cooler surroundings

• Loss of energy by a body can cause cooling

• Energy can become thinly spread in the large surroundings

• Objects or systems can store, gain and lose energy; energy can transfer between them

thermal energy transfers II: temperature difference

E2: Thermal energy transfers II

Syllabus / specification points:

• Energy natural transfers from objects or systems at higher temperature to ones at lower temperature

• Our bodies are usually at higher temperature than our surroundings, so we lose energy and we must replace it by ‘burning’ food

• We can reduce the rate of energy loss by heating the spaces we live in, thus reducing temperature difference

• We can reduce the rate of energy loss by using layers of insulation (clothing)



thermal energy transfers III: representing energy transfers

E3: Thermal energy transfers III

Syllabus / specification points:

• Energy transfers naturally from warmer (higher temperature) to cooler (lower temperature)

• A kettle supplies energy to water

• Some energy from a kettle with hot water transfers directly to the surroundings

• The water stores some energy, and you can make a hot drink.

• Some energy from the hot drink transfers directly to the surroundings. The surroundings get a little warmer, but the energy spreads thinly.

• You get a little energy from the hot drink, but energy also  spreads from you to the surroundings.


thermal energy transfers IV: the effects thermal energy gain

E3b: Thermal energy transfers IV

Syllabus / specification points:

• Money and energy transfer

• Money can be stored in a bank, and in a ‘piggy bank’

• Energy can be stored by hot material

• Transfer of energy to material can cause it to ‘change state’ – to melt or to boil

• Transfer of energy to material can cause its temperature to increase


Processes of thermal energy transfers

E4: Processes of thermal energy transfer

Syllabus / specification points:

• CONVECTION is a process of energy transfer involving movement of hotter liquids and gases through cooler material.

• The liquids and gases carry their energy store with them; energy can then transfer to the cooler materials that they mix with.

• The movement can become ‘convection currents’

• CONDUCTION is a process of energy transfer from particle to particle.

• Conduction happens best in metals, because there are strong forces between the particles

• RADIATION is a process of energy transfer by waves, similar to light waves but invisible to us


conservation of energy

EN10: Conservation of energy

Syllabus / specification points:

• Energy cannot be destroyed

• The total energy at the end of every process is the same as at the beginning

• However, energy can become thinly spread by thermal processes, and become dissipated





conservation of energy: motion without resistive forces

E10.E: Conservation of energy: motion without resistive force

Syllabus / specification points:

• The total energy at the end of every process is the same as at the beginning, so if there are no resistive forces the gravitational potential energy at the highest point matches the kinetic energy at the lowest point

• A pendulum, such as a playground swing, loses and gains gravitational potential energy and kinetic energy, in turn

• When there are is no need for work to be done to overcome resistive forces then there is no dissipation






conservation of energy: motion with resistive forces

E10.F: Conservation of energy: motion with resistive force

Syllabus / specification points:

• The total energy at the end of every process is the same as at the beginning, so if there are resistive forces the gravitational potential energy at the highest point matches the total of dissipated energy plus kinetic energy at the lowest point

• There is loss of energy, by dissipation, during every swing, so the maximum gravitational potential energy and the maximum kinetic energy gradually become smaller

• A source of energy is needed to replace the dissipated energy






Energy, provisional list, July 2021



E1         Thermal energy transfers I                                                           

E2         Thermal energy transfers II                                                          

E3         Thermal energy transfers III                                                         

E3.B.     Effects of gain                                                                             

E4         Processes of thermal energy transfer                                         


ENERGY SPECIAL: some essential Physics of energy balance and temperature stability of oranges, cakes and planets  

E4.B      ‘Higher rate’ isn’t the same as ‘more’                                         

E4.C     Balance and imbalance of thermal energy transfer                     

E4.D     Energy balance of a planet                                                          

E4.E.     Changing the atmosphere                                                          

E4.F      Changing the atmosphere, changing the energy balance         

E4.G     Higher and higher temperature?                                                 


E5         Work: mechanical energy transfer                                              

E6         Work and kinetic energy                                                             

E7         How to calculate kinetic energy                                                 

E8         Work and extra gravitational potential energy                            

E9         Calculating extra gravitational potential energy                         

E10        Conservation of energy                                                             

E10.B    Conservation of energy: motion with/without resistive force     

E10.C    Conservation of energy: falling without resistive force              

E10.D    Conservation of energy: falling with/without resistive force      

E10.E    Conservation of energy: motion without resistive force             

E10.F    Conservation of energy: motion with resistive force                  

E10.G    Conservation of energy: changes of KE + GPE during orbit      

E11        Energy stores                                                                           

E11.B     Energy storage by stretched springs and wires                       

E11.C     More energy transfers: in chemical changes                           

E11.D     More energy transfers: by waves                                             

E11.E     More energy transfers: in electric circuits                                 

E11.F     More energy transfers: in nuclear changes                               

E12        Heating water I                                                                          

E13        Heating water II                                                                         

E14        The snowman is melting                                                           

E15        Boiling dry                                                                                 

E16        Power I                                                                                      

E17        Power II                                                                                     

E18        Thermal conductors and thermal insulators                             

E19        Reducing energy loss through a wall                                        

E20        Efficiency I                                                                                 

E21        Efficiency II                                                                                

E22        Efficiency III                                                                               

E23        Reducing dissipation due to friction                                         

E24        Coal is old                                                                                 

E25        Biofuels                                                                                     

E26        Water flow                                                                                 

E27        Water waves                                                                             

E28        Underground I                                                                           

E29        Underground II                                                                           

E30        Wind turbines                                                                            

E31        Solar panels                                                                              

E32        Solar cells                                                                                   

E33        The nuclear power industry I                                                    

E34        The nuclear power industry II                                                   

E35        Clean energy?                                                                           







Copyright (c) David Brodie, 2019-2021

Photography: Adobe Stock