Fire – Science

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This task will enable students to explore their current understanding of Australian bushfire ecology.

A teenager from Sweden has posted a message on a Facebook wall. He has heard about bushfires in Australia, and wants to know more about how they affect the environment.

Guide questions for discussion:

• What does the class know about bushfires?
• How can this be explained to someone who does not know the Australian environment?
• How is bushfire part of Australia's ecology?
• What happens to the plants and animals after a fire? Are they all killed by fire?

Students consider terms that relate to bushfire ecology. How may they be explained to someone not familiar with Australia? Terms include: fire intensity, fuel load, weather conditions, seed germination, epicormic buds, lignotuber, coppicing, etc. Where do animals find food and shelter after a fire?

Students work in small groups initially. The class contributes ideas which are placed on a bubble diagram that illustrates how bushfire affects the environment. They then make a list of what they still need to know to answer the Swedish teenager's inquiry.

The heat is on

In this activity students research and report on Australian bushfire ecology.

Provide students with a lesson on how plants and animals are adapted to bushfires. In southern states, use information found on the Department of Sustainability and Environment website. In tropical regions, use the Learnline website.

Refer to Handout 2. What would students expect to happen to small native mammals after a fire? What does the data show about the survival of small mammals after a bushfire? What kind of change is there over time? Are the changes as dramatic as the students expected?

Write a report or produce a presentation about the way a range of plants and animals and their ecosystems are adapted to fire. Some starting questions include:

• How do plants and animals survive bushfires?
• What are some of the different strategies used by plants and animals to survive fire?
• What sequence of events occurs in an ecosystem after a bushfire?
• What kind of Australian ecosystems require fire for regeneration?

Resources

Investigating bushfires in the lab

In this task, students will design laboratory experiments to demonstrate properties of fire and flammable materials.

Students design laboratory experiments that test their hypotheses about Australian bushfires and the adaptation of plants. The design of experiments should include: concepts being tested, equipment required and safety measures. The teacher may choose the safer experiments for students to attempt.

Students describe the following:

• What will be tested?
• How will the experiment be designed? How does it test the hypothesis? Will a control experiment be required? What will the experiment measure?
• How will the experiment be conducted safely?
• What equipment and materials are required? How is the experiment to be conducted?
• What observations will be made?
• How will data be collected and recorded?

Examples of concepts that might be tested include:

• The flammability of materials in the bush or grasslands. Starting points:
  • Compare the moisture in plants.
  • Compare the exposure of plants to air.
  • Compare how different materials burn in controlled conditions.
• The influence of convection currents due to heat of fires and winds on bushfires. Starting points:
  • Use candles as a source of flames.
  • Show how supplying more oxygen to a flame increases burning.
  • Place a lit candle in the bottom of a glass measuring cylinder and use a wooden ruler to produce a convection current.
• The influence of humidity on the flammability of materials. Starting points:
  • Compare burning paper in dry and moist environments.
• Germination of seeds and response of seed cases after fire. Starting point:
  • Collect native seeds and seed cases.
  • Classify into types of seed cases and seeds.
  • Heat naked seeds and find out if they will geminate.
  • Heat seeds in their seed case and observe the response of the seed case before trying to germinate.
• The resistance of bark and soil to heat during heat during bushfires. Starting point:
  • Cover samples of bark with soil and with paper to see if they burn when heated by a flame.
• Alternative methods for retarding fire. Starting point:
  • Compare different methods to reduce the burning of paper by reducing oxygen, treating the paper, etc.

Resources

Management of fire-prone areas?

In this task, students use the internet to obtain various opinions about fire management and evaluate each critically.

Students will state their opinion about the use of fire to manage bushfire-prone ecosystems sustainably. Their opinion must be supported by evidence. To develop an informed opinion they should investigate:

• Prescribed fuel reduction burns and prescribed ecological burns
• A variety of land management opinions

Students should give reasons why they found some views on the Internet more credible than others. They can then develop a way of ranking their opinion against others presented in the class.

Resources