What are the properties of a gas? Material processes - Solids, liquids and gases - Gases Learning Points Gases do not have a fixed shape and so move to fill their container. The molecules in gases are widely spaced and move about quickly. Gases do not have a fixed volume and can be compressed. A Twig Curriculum Film. Delivering key learning points. Get straight to the facts in just three minutes – directly linked to core learning, Twig's curriculum films will fit neatly into your lesson plans.