We use water every day ... but what do you really know about it? Material processes - Solids, liquids and gases - Characteristics of water Learning Points Water is the only substance on Earth that occurs naturally in all three states. Liquid water freezes at 0°C. Liquid water boils at 100°C. 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.