Internal Energy and Changes of State


  • Internal energy = energy stored by particles that make up a system
  • Particles have energy in their kinetic energy stores = particles in system vibrate or move around.
  • Due to their positions = energy in their potential energy stores
  • Energy stored in a system = stored by its particles
  • Internal energy = total energy that its particles have in their kinetic and potential energy stores
  • Heating = transfers energy to particles = gain more kinetic energy and travel faster = increasing internal energy
  • This leads to a temperature change or state change. Temperature change = size of the change depends on the mass of the substance, what its made of, its specific heat capacity and energy input
  • Change in state happens when the substance is heated enough = particles have enough kinetic energy to break the bonds which hold them together
  • Heat a liquid → boils (evaporates) → becomes a gas
  • Heat a solid → melts → becomes a liquid
  • Internal Energy and Changes of State

  • Change of state = physical change, you don’t end up with a new substance. Just the same substance in a different form
  • Reverse a change of state = substance will return to original form and original properties
  • Number of particles don’t change, just arranged differently = mass is conserved

How long have you…? (present perfect 4) Exercises




Use the information given to create questions beginning with ‘How long…?’

• It is snowing.

• The weather is shining.

• John and Kate are married.

• My brother has gone on holiday.

• My aunty and uncle live in Canada.

• My sister is a teacher.

• I work at the chemist.

• I’ve known Susan since I was a baby.

• Jonathan is learning to speak to Mandarin.




Fill in the missing gaps in the sentences using the present perfect (=has/have + past participle)

• I have known Kate a long time.

• My brother has been playing the piano he was 11 years old.

• My mum and dad on holiday to America. They

gone since last Sunday.

• I Ben and Emma since primary school.

We to the same primary and secondary school.

• My sister learning to speak French because she
is going to France next month.



Use the appropriate words in the missing gaps.

have you lived       lives      to

has been       works        have known

I have bought       have worked.

• My sister in Spain. She is studying Spanish

with her friend Rosie. I Rosie since I was 5.

• Spencer like with Jamie. They have worked

together for 2 years.

• How long in Australia?

• a new dress for prom.

• He to Thorpe park.



Challenge: Create 4 of your own questions beginning with ‘How long……?’








1 2 3 4 5 6  

“Every accomplishment starts 
With the decision to try.” Gail Dever

++44 (0)1924 506010