Reactive Chemistry

What students will do

Working in pairs, students add water to sodium polyacrylate to produce a near-solid gel, then reverse the change with salt to demonstrate a physical change. They observe bi-carb soda, calcium chloride and phenol red react in a sealed ziplock bag, with colour change, gas production and temperature change all in one, then use digital thermometers to measure temperature change in two different chemical reactions side by side. Red cabbage water serves as a pH indicator to classify a range of chemical solutions as acids, bases or neutral. The facilitator demonstrates Elephant's Toothpaste, a rapid exothermic reaction, as a dramatic whole-class finale.

Learning outcomes

• Distinguish reversible from irreversible chemical changes using observable evidence including colour change, gas production and temperature change
• Investigate a reversible physical change using sodium polyacrylate, water and salt, and describe how the mixture's texture changes and changes back
• Observe a sealed-bag reaction and identify multiple signs that a chemical reaction is taking place
• Use digital thermometers to compare the temperature change produced by two different chemical reactions
• Use a natural pH indicator to classify a range of chemical solutions as acidic, basic or neutral
• Use scientific vocabulary to describe and compare physical and chemical change, drawing on the Elephant's Toothpaste demonstration

Curriculum links

• VC2S6U04·Core

  Changes to materials can be reversible, such as melting or freezing, or irreversible, such as burning, and new substances can be formed in a chemical change. View on VCAA ↗

• VC2S6I02·Core

  Investigations can be planned and conducted to test relationships and identify patterns, including fair tests where variables are changed, measured and controlled. View on VCAA ↗

• VC2S6H02·Related

  Scientific knowledge, skills and data can be used by individuals and communities to identify problems, consider responses and make decisions. View on VCAA ↗

• VC2S6I05·Related

  Investigations, including their methods and findings, can be evaluated, including by identifying possible sources of error and drawing conclusions. View on VCAA ↗