#
Activity: Straight line pictures

AOs |
Indicators |
Outcomes |
Learning experiences |
Cross curricular

Assessment |
Spotlight |
Links |
Connections

**Purpose**

By investigating how to create pictures with straight lines on a graphics calculator or a computer graphing programme such as Geogebra, students develop an understanding of the relationship between graphical, tabular and algebraic representations of linear functions.

Can be used either as an introduction to straight line graphs or as an interesting task to consolidate their understanding of the multiple representations of linear relationships.

**
Achievement objectives**

- NA6-7 Relate graphs, tables, and equations to linear, quadratic, and simple exponential relationships found in number and spatial patterns.
- GM6-8 Compare and apply single and multiple transformations.
- GM6-9 Analyse symmetrical patterns by the transformations used to create them.

**
Indicators**

- Demonstrates understanding of relationships, including linear, quadratic (y=ax2+bx+c, where a is not zero) and simple exponential relationships (y=ax,where a is a positive integer).
- Makes connections between representations such as number patterns, spatial patterns, tables, equations and graphs.
- Identifies and uses key features including gradient, intercepts, vertex, and symmetry.
- Reflects, rotates, enlarges and translates figures.
- Describes transformations used to create patterns using key features.

**
Specific learning outcomes**

Students will be learning how to link multiple representations of linear relationships using technology.

**
Planned learning experiences**

The teacher introduces students to the graphing technology and shows them how to input a simple linear function (for example, y=x) and then view the graph created.

Working in groups, they are given a series of pictures made with straight line graphs. Pictures could include:

- those included here (see
resource sheet)
- rain from the east
- rain from the west
- window blinds
- a tent
- Patiki patterns
- a starburst
- a firework
- create their own picture and challenge other students to recreate it.

What do you notice about the equations/gradients/y-intercepts for each of these line graphs?

Students investigate which functions are used to create the pictures, and write the equations of the functions. The intention is not that these are pre-taught – but that the students discover how to get a horizontal line/negative gradient etc in their groups.

The teacher works with different groups and questions what they have discovered, gives hints where necessary (such as working through tables to see the pattern and then write the equation), or facilitates the sharing of the thinking of another group to get them past stalemates, for example, 'Sarah could you tell the class how your group got the window blinds picture?'

This may take two or more lessons, followed by time to generalise their learning, either through sharing ideas or by completing individual notes.

Teacher introduces the formula **y = mx + c** and students describe the effect on a line of changing **m** and changing **c**.

Teacher relates features to vocabulary such as gradient and intercept.

### Possible adaptations to the activity

Students extend to draw vertical lines (draw rain with no wind).

**Extension **

**Similar activity with parabolas**

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##
Cross curricular links

- Graphics and design
- Linear relationships in science

##
Planned assessment

This teaching and learning activity could lead towards assessment in the following achievement standard:

- 1.3 Investigate relationships between tables, equations or graphs.

##
Spotlight on

### Pedagogy

- Facilitating shared learning:
- Students working in groups.
- Shaping mathematical language.

- E-learning:
- Using technology to explore concepts.

## Key competencies

- Thinking:
- Students use mathematics to model real life and hypothetical situations and they create models.

- Using language, symbols, and texts:
- Students use the language of algebra to communicate and reason.
- Students interpret visual representations such as graphs and diagrams.

- Participating and contributing:
- Students work in groups with everyone contributing.

### Values

- Students will be encouraged to value innovation, inquiry, and curiosity, by thinking critically, creatively, and reflectively.

### Māori/Pasifika

### Planning for content and language learning

- Identify the learning outcomes including the language demands of the teaching and learning:
- What language do the students need to complete the task?
- Do the students know what the content and language learning outcomes are?

- Provide multiple opportunities for authentic language use with a focus on students using academic language:
- Is the language focus on key language?
- Do I make sure the students have many opportunities to notice and use new language?

- Ensure a balance between receptive and productive language:
- Are the students using both productive (speaking, writing) and receptive (listening, reading) language in this lesson?

- Reinforce vocabulary of linear relationships via student discussion.

##
Links

**Nazca Lines – Peru**

##
Connections

- Lovitt, C., & Clarke, D. (1992). Algebra walk.
*MCTP professional development package: Activity bank volume 1* (p. 213). Carlton, Victoria: Curriculum Corporation.
- Lovitt, C., & Clarke, D. (1992). Tell me a story.
*MCTP professional development package: Activity bank volume 1* (p. 253). Carlton, Victoria: Curriculum Corporation.
- Lovitt, C., & Clarke, D. (1992). Speed graphs.
*MCTP professional development package: Activity bank volume 2 (p.567)*. Carlton, Victoria: Curriculum Corporation.
- Lowe, I. (1991). Distance-time graphs.
*Mathematics at work - modelling your world: Volume 1 *(p. 355)*. *Canberra, ACT: Australian Academy of Science.

Download a Word version of this activity:

Last updated July 30, 2015

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