Year 7 Science

Matter

Guidance for Teachers and Parents.

Lesson 2 - Getting Hot - Changing State

National Curriculum: Programmes of Study for Sc3

Work on the classification of materials, the ways in which materials can be changed related to pupils' knowledge about particles as constituents of matter.

Key Elements

(a) Different materials change state at different temperatures.

(b) To relate change of state to energy transfer.

(c) Materials expand and contract with changes in temperature.

(d) When physical changes take place, mass is conserved.

Objectives

Pupils should:

(a) be able to recognise and an understanding of a change of state - freezing and melting.

(b) understand that temperature change causes expansion and contraction in materials.

Outcomes

Pupils are be able to:

(a) use and understand the concepts of melting, freezing, evaporation and condensation and apply them to the appropriate change of state.

(b) research and interpret data on melting and boiling points.

(c) understand that mass is conserved when materials change state.

(c) make predictions about the effect of temperature change on solids, liquids and gases.

Notes

This lesson is preparing the way for an examination of solids, liquids and gases in terms of particle arrangement. The conservation of mass is important here in that increases of size can be explained in terms of greater separation of particles.

The students predictions for the last three experiments can be confirmed experimentally. The expanding wire experiment is best with about 30cm of copper wire. A hanging mass should be attached away from the heat source to keep the wire in tension. Beware of the hot wire - leave to cool before dismantling.

Extension work can look at how expansion of materials with temperature has a use in measuring devises e.g. thermometers. Expansion can exert considerable force.

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