This a rusty tractor engine, captured at Jurien Bay, WA.
Over the next few weeks we will be doing many different experiments, including turning grass into paper. After you have finished this unit of work, you should be able to answer the following questions:
- What are the two main differences between physical change and chemical reactions?
- What are four signs that new products are formed during a chemical reaction?
- Name four ways you can increase the rate of a reaction.
Freezing, melting, evaporation and condensation are all physical changes of state in which molecules of a substance gain or lose kinetic energy. Many common changes that occur around us are actually chemical reactions – when iron rusts, apples go brown, silver tarnishes or copper develops a green tinge, oxidation is occurring. Combustion (burning) is also a form of oxidation. In a chemical reaction new products are formed and this may result in a colour change, a precipitate being formed, the release of gases or energy in the form of light or sound. The following resources may help you to learn about chemical reactions:
- “Top Ten Amazing Chemical reactions” – identify what change/s have occurred that indicates a chemical reaction.
- Preparing gases – A BBC Bitesize activity
- Chemicals in the laboratory and home – Another BBC Bitesize activity.
- Chemical change Song – A Teacher Tube video
- Chemical vs Physical – Another Teacher Tube video
- Test yourself about Rates of Reaction.
- Student Worksheet: rates-of-reaction
Check out our Voicethread about Chemical reactions:
What would you like to learn about in Science next? Please go to the Wallwisher and leave a post-it note letting me know what you are interested in doing in Year 8 Science.