Teaching Sequence

Work through this resource material in the following sequence:

10 minutes

Tune in: Activating prior knowledge

10 minutes

Find out: The three requirements for fire

30 minutes

Take action: Is the model accurate?

10 minutes

Reflection

Please make sure to read the About Cool Burning Factsheet.

Tune In: Activating prior knowledge

Step 1.

Explain: in this lesson, students will be looking at the fire triangle model as a way of understanding fire and how it behaves.

In order to do this, it is useful to have some prior knowledge of what fire is.

Stand on the Line

Using string, masking tape or chalk (this activity could be done outside) create a line on the floor/ground, long enough for all students to place themselves along.

Explain to students that one end of the line means 'strongly agree' and the other end means 'strongly disagree', while the halfway point means' neither agree nor disagree' (consider adding small signs with these titles along the line). Invite students to respond to a range of statements by positioning themselves along the line, according to whether they agree or disagree with the statement.

With each statement, engage students in a brief discussion, highlighting some of the key points identified in each statement.

Read out the following statements, and use the suggested responses to guide discussion around each point:

I know how to describe fire. Fire is the visible effect of the process of combustion (a special type of chemical reaction). Fire occurs between oxygen in the air and a fuel. The products left after this chemical reaction are completely different from materials they started out as.
I know what a chemical reaction is. A chemical reaction occurs when chemicals combine to form new substances with new properties.
I know an example of a fast chemical reaction and a slow chemical reaction. An example of a fast chemical reaction is an explosion, such as the exploding of fireworks or a bomb. An example of a slow chemical reaction is rusting (or oxidisation).
I know how to describe the term 'burning'. Burning is a rapid type of chemical reaction that produces large amounts of heat and light.
I know which greenhouse gases are released through burning. One of the chemicals produced during burning is carbon dioxide, which we now refer to as a 'greenhouse gas'. Other greenhouse gases that are produced during burning include methane and nitrous oxide.
I know what the fire triangle model is. The fire triangle model of understanding fire is used to explain the three requirements to start and sustain a fire. These three things are: 1. A source of heat is required to start and sustain a fire; 2. A source of fuel is needed to burn; and 3. An adequate supply of oxygen is needed for a burning/chemical reaction.

Step 2

Show students the edited image below (also available here: F i r e T r i a n g l e M o d e l - N o l a b e l s).

Explain: The fire triangle model of understanding fire is used to explain the three requirements to start and sustain a fire.

Discuss:

What do you think the three requirements might be?

Find Out: The three requirements for fire

Step 1. Explain:

The Black Summer bushfire season in Australia (2019/2020) and explain that because of such events, many of us associate fire with negative events like this.

However, fire can also be used in a positive way to manage landscapes by adopting a practice of cool burning.

Share the following with students (also available on the Student Worksheet):

Cool burns are a land management technique. Started soon after the wet season, before the grass completely dries out, cool burns do not damage plants, seeds or animals to any significant extent. During a cool burn, the grasses on the ground burn slowly, allowing most of the small animals to escape. Seedlings, green grass, tree trunks and fallen logs are not burnt or damaged. The rising heat from the burning grass usually won’t singe the eucalyptus leaves above. Overnight, the cool moisture in the air will put out any remaining fires before the morning.

The practice of cool burning has been used by Aboriginal and Torres Strait Islander peoples for many thousands of years. However, in recent years, scientists from around the world have become more and more interested in these practices one way of managing devastating bushfires.

Step 2. Watch:

The problems of hot burns - (https://vimeo.com/79474010)

Once students have completed the thinking routine you could invite them to share some of their thoughts with a peer or with the class.

Step 3. Discuss:

What are some differences between cool and hot fires?
What are some problems with hot fires?
Do people benefit from the use of fire?
What are some safety issues surrounding the use of fire?

Step 4. Share the following image:

(Image also available here: Fire Triangle Model)

The fire triangle model of understanding fire is used to explain the three requirements to start and sustain a fire. These three things are:

A source of heat is required to start and sustain a fire
A source of fuel is needed to burn
An adequate supply of oxygen is needed for a burning/chemical reaction.

More information about fire can be found on the Fire Factsheet.

Step 5

A candle can be used to demonstrate the fire triangle.

Discuss:

When a candle is burnt:

What is the fuel?
Where does the heat come from?
Where does the oxygen come from?

Step 6. Discuss:

The fire triangle is used by firefighters in countries like Australia and the USA to explain how fires work. They say if one of these three elements is not present then there can’t be a fire. Do you think this is true? How can we test this?

Take Action: Is the model accurate?

Step 1

Remind students of the image of the fire triangle they looked at earlier, and discuss the three elements on the triangle.

Inform students that they will be working in groups to design and conduct an experiment to help them explain what is needed to keep a fire going. They are to explain the role of fuel, heat and oxygen.

Remind students that their experiment should be a fair, repeatable test, and that they need to control the variables.

Students should fill in the experimental design table on their Student Worksheet. The rubric below can be used for assessing their design.

Experiment design criteria rubric

Section	Description	Marks
Aim	The specific purpose of the experiment. Formatting tip: Sentence starts with 'To...'	2
Hypothesis	Prediction of the outcome. What do you think will happen? Formatting tip: If... then... (something will occur)	2
Materials	Equipment used to perform the investigation.	2
Risk assessment	A list of any safety concerns and how you will control them.	4
Method	Point-form notes listing key steps, the number of trials and how accuracy was maintained. Formatting tip: Use past tense, no 'I' or 'we'.	5
TOTAL		15
COMMENTS

Note: Students must submit their experimental design for teacher feedback before they are allowed to do the experiments.

Step 2

Allow students time to complete their experiments. Throughout the process, the teacher should emphasise the importance of risk management and remind students of your Lab Safety Rules.

Students should record their observations in the results table (available on the Student Worksheet).

Step 3

Once completed, students should answer the discussion questions (available on the Student Worksheet). In addition, invite students to write a paragraph in response to the following statement:

Fire scientists should be seeking knowledge from First Nations land managers to help manage bushfire risk.

Reflection

Invite students to reflect on this lesson by completing the following (also available on the Student Worksheet):

How did your experiment help you understand the fire triangle model?
What is still confusing for you?
How did your experiment help you understand the difference between cool burns and hot burns?
If you were able to repeat this experiment, what would you change and why?

Teacher reflection

Take this opportunity to reflect on your own teaching:

• What did you learn about your teaching?
• What worked well?
• What didn't work well?
• What would you share?
• Where to next?
• How are you going to get there?

The Fire Triangle Model (Secondary)

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