Physics · KS3 Y7 · Matter & Particles

Melting and freezing

Melting and freezingFree3:32Heddy Score 3 of 7, below the standard

What you need to know

  • Particles have kinetic energy because they move, and potential energy because of the forces between them.
  • Internal energy is the total kinetic and potential energy of all the particles in a system.
  • Heating raises the internal energy and can cause melting and boiling; cooling lowers it and causes condensing and freezing.
  • In a change of state mass is conserved, and the change is physical, so it can be reversed.
  • Evaporation happens only at the surface, where some particles have enough energy to escape.

In this clip

0:08–3:06Internal energy
Also coversMelting and freezing
Also coversEvaporating, boiling and condensing
Heddy Score3/7, Below the standard
See the seven stars
  • Trusted source · passed. The creator's own upload, live and playable here.
  • On the map · not judged yet. A teacher watched it: it mainly teaches this map topic.
  • Spec-true · not judged yet. Accurate, and right for the current UK specification.
  • Focused · passed. One idea, short enough to watch in one go.
  • Accessible · passed. Good captions, clear sound and pictures.
  • Safe for children · not judged yet. Right for 11 to 16 year olds, with no sales pitch.
  • Proven · not judged yet. Earned from our students: they learn from it, find it helpful and watch it to the end.
★ passed · ☆ pending · ✕ failed
Our students

Not enough students yet

Our own students' answers. These are what move ★7 Proven.
On YouTube

529K views · 5.39K likes · Freesciencelessons 995K subscribers

As reported by YouTube on 2026-11-02. Not part of the Heddy Score.
How the Heddy Score works

Why we picked it

Gives the exact GCSE definition of internal energy and links it to changes of state.

Freesciencelessons on YouTubechecked 2026-10-22

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