Embedded Files
Topic 1
STAGE 3 TEACHER RESOURCE
NSW National Parks staff monitor a bushfire in a national park
This topic covers the fundamentals of Australian bushfires and explores the diverse features and characteristics of places and environments.
At the end of this topic, students will be able to:
explain what bushfires are and how they start
describe when and where bushfires occur
identify factors affecting the frequency and intensity of bushfires.
What are bushfires?
What are bushfires?
Bushfires are fires that burn through natural spaces, including bushland, forests and grassland. These fires are often unpredictable and difficult to control.
Bushfires can cause significant damage to people, our homes and the communities we live in. They can be devastating for the natural environment, impacting plants, animals and ecosystems.
However, in the right time and place, bushfires can actually restore balance to the natural environment and play a key role in maintaining healthy ecosystems.
Understanding the science behind bushfires helps us to:
identify and minimise harmful impacts of bushfires
prepare communities at risk
harness the positive benefits to protect natural environments
and heritage.
Bushfires can destroy large areas of natural environment when out of control
How do bushfires start?
How do bushfires start?
As with all fires, bushfires need three elements to burn.
Heat
Oxygen
Fuel
Take one element away and the fire goes out.
These three factors also affect the frequency and intensity of bushfires.
Understanding these three elements and how they interact is very important in managing bushfires and preventing them from occurring in the future.
Click on the fire triangle image to learn more about how bushfires start.
The three natural elements of the fire triangle
Oxygen is a gas naturally found in the air around us, not possible to see with the human eye. The amount of oxygen in the air changes depending on the altitude of a place. For example, places with high altitude, such as the top of a mountain, have less oxygen in the air than places of low altitude. High oxygen levels can increase the intensity of a fire. If there is no oxygen, the fire will go out.
Heat is the energy source that initiates the combustion process and keeps it going. In the case of bushfires, heat can come from various sources such as the sun, a lightning strike, human activities like camping or radiant heat from a car engine. The heat causes the fuel to reach its ignition temperature and start burning.
High ambient temperatures during the summer months can lower the ignition temperature of the fuel, making bushfires more likely. Bushfires, once started, create intense heat making it harder to keep them under control.
When talking about bushfires, fuel is any material that can be burned. Dried grass and leaf litter on the ground are two of the most common bushfire fuel sources. These are found in abundance in many of our natural spaces. And in extreme conditions, green leaves and even whole tree canopies can catch fire. The more fuel there is, the higher chance a bushfire can start, the more intense it can be and the longer it can keep burning.
When and where do bushfires occur?
When and where do bushfires occur?
A satellite image of the Black Summer bushfires © 2021 Western Australian Land Information Authority. Reproduced by permission of the Western Australian Land Information Authority.
There are certain months of the year when bushfires are most likely to happen and also particular places that experience more bushfires. The higher risk of a bushfire starting is usually because of hotter temperatures and lower rainfall.
The time of the year when bushfires are most likely to happen are known as ‘bushfire seasons’ or ‘bushfire danger periods’.
According to the NSW Rural Fire Service, the most dangerous period in NSW is between 1 October to 31 March. This is when our summer heat patterns start to emerge, and the lands become hot and dry – creating ideal bushfire conditions. Wind, temperature, humidity, and rainfall all affect bushfire behaviour.
Have a look at the map of Australia from the 2019/20 bushfire season. What do you notice about where the bushfires happened? A large percentage of bushfires during this bushfire season were located in south-eastern Australia. This is also where they are usually most likely to occur in any year, because this area is hot and dry over summer. Bushfires also happen in western Australia during hot and dry months.
Refer to the Maps Slides presentation to discuss with students why maps are important, in the context of learning about bushfires.
What influences the frequency and intensity of bushfires?
What influences the frequency and intensity of bushfires?
Seasonal weather patterns [2:58]
Seasonal weather patterns [2:58]
Seasonal weather patterns create ideal bushfire conditions in different parts of the country at different times. These weather conditions influence the size, intensity, speed and predictability of bushfires. This ultimately impacts how dangerous they are to the community.
Climate change [2:18]
Climate change [2:18]
According to a team of climate scientists from the World Weather Attribution, climate change raised the Australian bushfire risk by 30%. This video discusses factors contributing to this increased bushfire risk, as well as significant weather events elsewhere in the world affected by climate change.
Activities
Activities
Fire triangle drawing
Draw a coloured diagram to show the three key natural elements needed to start a fire. Write a definition of what each element is under the diagram.
Locating bushfire risk areas
Using Google Maps online as a reference, sketch a road/street map to show bushfire risk areas between home and school.
Understanding extreme bushfire conditions
Write an article for the school newsletter (or local newspaper) to inform others about what bushfires are, where they occur and why bushfires are becoming more frequent and intense.
Page updated
Google Sites
Report abuse