Suspension A mixture in which particles of a material are dispersed through- out a liquid or gas but are large enough that they settle out. Particles are insoluble, so they DO NOT dissolve in the liquid or gas. Particles can be separated using a filter. Examples: Salad dressing Medicines that say “shake well before use”
Colloids A mixture in which the particles are dispersed throughout but are not heavy enough to settle out. Made up of solids, liquids and gases. Examples : Mayonnaise Stick deodorant milk
Mixing Pure Substances • Pure substances can be mixed together to form solutions that are liquid, gas or solid. • Most metals we use are combinations of two or more metals mixed together.
Alloys • An alloy is a homogeneous mixture of metal with other substances. • Alloys allow scientists to design metals that have specific properties depending on what they are used for.
Metals • http://www.brainpop.com/science/matterandchemistry/metals/preview.weml
How an Alloy is Made • Steel is formed in a process that takes iron from iron ore and carbon from coal. • Small amounts of other metals are mixed in to give the metal specific properties.
Uses of Alloys • Thousands of years ago civilizations melted tin into copper to create a new substance called bronze. • Bronze was used to create jewellery, armour, tools and weapons.
Modern Alloys • Metallurgists (people who study metals) have created many different alloys, each having its own specific properties. • Aluminum is lightweight and used in alloys to make engines, airplanes and bicycle frames.
Text Book Questions • Page 43 • 1 • 2 a, b • 3 • 4