Animations and Videos: Substances

These downloadable videos and animations are part of the multimedia package Stuff and Substance, and are intended to be used to establish the concept of a substance. The individual video and animation files are provided separately here to allow flexibility in their use. The Stuff and Substance multimedia package provides a series of interactive pages that can be used by teachers or students in the classroom, including supporting commentary and questions, animations, videos, images, and teachers’ notes.

Key steps in the development of understanding are:

The concept of a substance is introduced through melting behaviour: a substance is a kind of stuff which has a definite melting point.

• A particle model is introduced to explain why a substance can exist in both the solid and liquid states and why different substances have different melting points.
• The particle model is used to predict the possibility of the gas state and ‘gases’ are understood to be substances which happen to have boiling points below room temperature.
• A substance can be in any of the three states and there is nothing special about substances room temperature states.
• Density is another property which can be used to identify substances.