Teaching sequence

5 minutes - Tune in: Ball throwers for dogs
20 minutes - Find out: What is Newton's Second Law of Motion and how did Indigenous Australians use this knowledge in the use of their hunting spears?
15 minutes - Take action: Comparing estimates of forces of spear throwers
10 minutes - Reflection: What are the benefits of looking at First Nations knowledge before discussing phenomena from the perspective of Western science?

Tune in: What is the science behind ball throwers for dogs?

Step 1.

Show the video below to the class and guide students through a discussion. The video shows a range of ball throwers in different sizes with different features. These are listed below.

26L - Blue 26-inch thrower with an oversized tennis ball
26M - Orange 26-inch thrower with a medium-sized tennis ball
12M - Green 12-inch thrower with a medium-sized tennis ball
Alternative balls - ultra ball, glow ball, fanatic ball

Ask students to think about their initial impressions of the ball throwers when they are introduced and possible answers to the following questions. Encourage them to use the mind map on their worksheets to connect their ideas.

^{Image source: Chuckit! Fetch Games}

Which dog thrower might throw the ball farthest? Why?
What are some design features of the thrower that would increase the distance it would throw?
Which ball might travel the furthest distance? Why?
What are some design features of the ball that would increase the distance it travels?
What other variables might affect the distance of a throw?
Why is it easier to throw the ball with this tool rather than use your arm? Can you think of any other examples?
What is the force in the ball thrower examples? What affects the overall force of the throw?

ChuckIt! Ball Launcher - Leerburg (youtu.be/pehQp5VFDPY)

Find out:

What is Newton's Second Law of Motion and how did First Nations peoples use this knowledge in the design and use of their hunting spears and spear throwers?

Step 1.

Explain to students that Isaac Newton was an English scientist in the 17th century and is considered “the father of modern physics”. He was curious about the impact of forces upon objects and how these forces could be described in mathematical terms. Newton developed three laws of motion.

His second law of motion states that Force = Mass x Acceleration.

Step 2.

Show the class this video showing a simple explanation of the Second Law of Motion. if you have already covered this theory, the video could act as a refresher. If you haven’t covered the theory, it could serve as an introduction.

Force, Mass, and Acceleration: Newton's Second Law - GCFLearnFree (youtu.be/-7JoUUcvaSI)

If you haven’t already covered this theory in class, please refer to the Teacher content information for some information to give to your students regarding forces, Newton's Second Law and the terms used in this law.

Step 3.

Explain to the students that we can represent forces using force diagrams. A force diagram shows the relative size and direction of all of the forces acting upon an object in a certain situation. Show the students the following force diagram of a person shooting a basketball. If you want some more information on this, please refer to the teacher content information.

Ask the students to draw a stick figure of a person using a dog thrower on the worksheet. Ask them to label the various components they can think of from the lesson or their previous knowledge. If you have covered types of forces and/or force diagrams, ask the students to draw a force diagram of the scene with the forces acting on the dog thrower and the ball.

Step 4.

Explain to students that Aboriginal and Torres Strait Islander peoples have conceptually understood Newton's second law of motion for many thousands of years in constructing weapons such as spear throwers.

A spear thrower (shown in the image below) increases the launch speed of spears. This shows that First Nations peoples have an understanding that maximising the time during which the force acts leads to an increase in speed.

First Nations clans who used spear throwers had their own name for the tool in their own language. Woomera is a word of the Dharug language of the Eora people, Traditional Custodians of the Sydney region, for a traditional spear-throwing device. For the Pitjantjatjara people of Central Australia, it is known as a “Miru”, and for the Taungurung people of Central Victoria as a “Kurruk” or “Murriwan”.

Step 5.

Show the students this video which clearly demonstrates the construction and use of a spear thrower from the Warlpiri people in Mparntwe (Alice Springs) on Arrente Country.

Meet the Woomera - CuriosityShow (youtu.be/gBI6-vpp0Bg)

Some possible topics for discussion with the class could include:

How does the design of the spear allow for more force to be applied to the spear?
What forces are acting on the spear?
What do you think would happen if you changed the mass of the spear?
What do you think would happen if you changed the length of the spear thrower?
Why does the angle at which the spear is thrown matter?

Step 6.

Explain to the students that they will be investigating 5 different spear throwers from a variety of First Nations clans. The students will need to look closely to see the details of the construction. The spear throwers can be found at the following website - https://www.aboriginal-bark-paintings.com/aboriginal-woomera/

“Meru” by the Noongar people of South Western Australia
“Balur” or “Jarin” by the Dyirbal people of North Queensland.
“Kuruk” by the Dja Dja Wurrung people of central Victoria.
“Bitidj” or “manjal” by the Yolngu people of Arnhem Land.
“Yarn.gal” by the Ngarinyin people of the Kimberley

Lead the students to discuss in groups each of the five spear throwers. Divide the class into five groups, each to discuss one of the spear throwers.

Encourage students to discuss the below points and then sketch their spear throwers

What do you immediately notice about the spear thrower?
What interesting features does it possess, and how might these affect how it works?
Think about the length, mass, weight distribution, shape and flexibility of the spear thrower; how might these features affect its use.
On your sketch, name the spear throwers' key materials and key features
Label the forces which might influence its effectiveness.

Step 7.

Ask the groups to share their reflections on each spear and add the points to a table like the one below for the class to see. Encourage students to combine key points from the five descriptions into the table on their worksheet, or into their notebooks. Once you have discussed all five spear throwers, pose the following question to the class:

Assuming the same person threw an identical spear in terms of length and mass with the same effort, which of the spear throwers do you think would throw the farthest? Why?

Spear Thrower	Key Information
'Meru'
“Balur” or “Jarin”
“Kuruk”
“Bitidj” or “manjal”
“Yarn.gal”

Take action: Combining Cultural Knowledge Construction with Western Science’s Scientific Method.

Step 1.

Explain to students that an important part of understanding the scientific method is to take data from two different perspectives and look for similarities and differences. Explain that in this lesson, the students have looked at the laws of motion from the perspective of First Nations cultural practices and Western scientific observations and findings. Ask the students to answer the following questions in their worksheet/notebook.

First Nations peoples along with many other cultures, designed their spear throwers and many other cultural practices and behaviours before Newton had ever developed the second law of motion. What does this tell you about science and scientific discovery?
- Suggested Solution: Science and the scientific method are practised by all peoples of all nations across the world. Some cultures may not call it 'science', but that doesn't mean they don't understand 'scientific' principles. Likewise, scientific discoveries happen independently over time and are used to enrich the lives of the people making them. E.g., spear throwers are not unique to First Nations peoples; they were also used by Aztec cultures using very similar designs. Same scientific understanding, similar devices, different continents at different times (before colonisers even knew their lands existed!)
How can you use Newton's second law of motion to explain the design and use of Indigenous spear throwers?
- Suggested Solution: Throwers allow a greater force to be applied to the throw of the spear, allowing it to travel further and faster, applying greater force to the object the spear hits.

Are there elements of spear-throwing practices that you do not understand?
Were these important to your overall understanding of the topic?

Reflection

This can be a short group discussion, or students can take notes for a deeper reflection after the class. Read the following question and allow students to discuss or write down their responses.

What are the benefits of looking at First Nations knowledge before discussing these scientific principles from the perspective of Western science?

You might also like to reflect on the lesson with your students through a See, Think, Wonder visible thinking routine in order to encourage thoughtful interpretation of the students' observations throughout the lesson. Ask students the following question.

Throughout the lesson, you have discussed how First Nations peoples understood the concept of forces and the laws of motion. From what you have learnt and discussed today, what have you seen? What does this knowledge make you think and wonder?

You may like to reflect on the content covered and questions discussed at the beginning of the lesson using the following prompts.

What are the forces which act upon an object which is thrown?
What happens to the acceleration of an object when the other factors are changed? What are those factors?
How does learning from real-world examples of forces and the laws of motion compare to learning about these concepts as a mathematical formula?

First Nations Physics: Force, Mass and Acceleration in Indigenous Spear Throwers

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