These downloadable videos and animations are part of the multimedia package Stuff and Substance, developed by the Gatsby Science Enhancement Programme (SEP). They can be used to develop the idea that mixtures do not have precise melting and boiling points.
Using properties that depend on the material only to distinguish between a pure sample of a substance and a mixture of substances is an important idea. Students tend to rely on ‘known history’ to identify mixtures (i.e. have things been mixed together to make it) rather than properties that can be tested. This thinking does not allow students to distinguish mixtures from substances that are compounds. These resources show that mixtures do not have precise melting and boiling points. The particle animation, used within the Stuff and Substance package, represents air as a mixture of substances in the gas state.
These video and animation files form part of the resources in the section Melting Behaviour in the Stuff and Substance multimedia package, which provides a series of interactive pages that can be used by teachers or students in the classroom.
HEALTH and SAFETY
Any use of a resource that includes a practical activity must include a risk assessment. Please note that collections may contain ARCHIVE resources, which were developed at a much earlier date. Since that time there have been significant changes in the rules and guidance affecting laboratory practical work. Further information is provided in our Health and Safety guidance.