Animations and Videos: More about Mixtures

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 about 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. This section builds on ideas introduced earlier on in Stuff and Substance.

Further developments of understanding are:

• The intrinsic motion of particles in the liquid and gas states gives rise to mixing without external agitation i.e. diffusion phenomena.
• The rate of evaporation (below boiling point) depends on the surface area, temperature and bulk air movement (strength of breeze/wind). These effects can be explained by the particle model.
• The rate of dissolving depends on the surface area (solute in solid state), temperature and amount of stirring. These effects can be explained by the particle model.
• Paper chromatography is a method for separating mixtures.