# Mailboxes

Purpose

In this unit students will research, design, make and test a cardboard letterbox, applying their knowledge and understanding of the standard measure, centimetres. They will also undertake a statistical investigation into the use of both electronic and letter mail.

Achievement Objectives
GM2-1: Create and use appropriate units and devices to measure length, area, volume and capacity, weight (mass), turn (angle), temperature, and time.
S2-1: Conduct investigations using the statistical enquiry cycle: posing and answering questions; gathering, sorting, and displaying category and whole-number data; communicating findings based on the data.
Specific Learning Outcomes
• Recognise that mail is both physical and electronic.
• Use standard measures of length to investigate the sizes of items of letter mail.
• Research letterboxes and recognise optimum design features.
• Use standard measures of length to design and make a letterbox.
• Record the design process, including using appropriate symbols and abbreviations to record length measurements.
• Pose an investigative question, plan a questionnaire, gather and sort data, display and discuss findings, and present these.
• Explain how technology both reflects and changes society and the environment, and increases people’s capability.
Description of Mathematics

At level one the students have been learning to recognise the attribute (of length), and have come to understand that measurement units are countable and that they can be partitioned and combined. When measuring length they realise that there should be no gaps or overlaps. The student is developing an understanding of a linear scale, recognising that it is made up of units of equal size that are known as ‘standard units’ because they are understood by everyone.

They are learning to align zero with the start of the item being measured, and to accurately reposition the ruler when required to measure a length longer than the ruler. In becoming familiar with metre and centimetre units of measure, the student is learning to use the abbreviations m and cm when recording length measures. Half or ‘a little bit’ are used to refer to part measures.

The student participates in planning and collecting appropriate data to answer a question that has been composed with the support of the teacher (as required). The student is learning to sort the data, use tally marks to keep track of response numbers, and present these data using a bar graph. Key teaching points for the bar graph data display are that the numbers on the vertical axis label points, not spaces, and that the height of the bar shows the total in the category. The columns should have spaces between them because the data are discrete.

The student is learning to discuss the findings, give an appropriate answer to the investigative question and suggest effects of their findings.

Associated Achievement Objectives

Technology
Technological Practice

• Develop a plan that identifies the key stages and resources required to complete an outcome.

Characteristics of technology

• Understand that technology both reflects and changes society and the environment and increases people’s capability.
Required Resource Materials
• Letterbox picture (Attachment 1)
• Computer with inter/intranet connections
• Used envelopes of various sizes
• 30cm rulers
• Pencils
• Cardboard shoe boxes
• Stiff cardboard
• Scissors
• Craft knives
• Glue
• Parcel tape or wide cellotape
• Paint, paintbrushes
• Graph paper
• The Jolly Postman, by Janet & Allan Ahlberg
Activity

Whilst this unit is presented as sequence of five sessions, it is expected that any session may extend beyond one teaching period.

#### Session 1

This session is about researching measurements associated with letter mail and letterboxes.
Consider whether students will work individually or in pairs.

SLOs:

• Recognise that mail is both physical and electronic.
• Use standard measures of length to investigate the sizes of physical letter mail.
• Research letterboxes and recognise optimum design features.

Activity 1

Begin by reading school intranet messages. Discuss electronic mail and ask what other ways we receive mail. Write the word ‘mail’ on the class chart/modeling book. Brainstorm other forms of mail, recording associated words/ideas.

Activity 2

Read The Jolly Postman, by Janet & Allan Ahlberg. Emphasise that letter mail comes in different sizes.

Activity 3

Display the picture of a letterbox. (Attachment 1) Discuss its features and what ‘job’ it has to do: receive mail of different sizes, keeping it safe and dry. Notice the size of the box, the size of the letter slot and the newspaper/parcel space.
Explain that the students will be making their own cardboard letterboxes.
Ask. “What do we need to know before we make our own letterboxes?” Record student responses. (Guide discussion to include ‘the size of the mail/letters’.)

Activity 4

Make available paper, pencils, 30cm rulers, used envelopes of assorted sizes. Have one student demonstrate how to use a ruler to measure an envelope. *Highlight the importance of aligning the edge of the envelope with zero, and of having the ruler aligned with a straight edge. Together, practice reading the length measure, including expressing part measures.
Model how to record the measure, correctly using abbreviations. Explain that students are going to measure and record various sizes of letter mail. Have students order a selection of envelopes from smallest to largest, draw these and record the dimension measurements.

Activity 5

As a class, talk about their measures and agree on an optimum size range for the letterbox, the letter slot, and the newspaper or parcel space, giving reasons why. Record this as a range (no smaller than x and no bigger than y), with a diagram.
nb. If a bulk supply of standard size shoeboxes is available for use, for ease of construction, consider these as optimum size.

Activity 6

Explain that if the Jolly Postman were delivering letters in the school neighborhood, some of the letterboxes may not be so easy for him to use because not all letterbox designers have researched letter size.
Go on a class walk in the school street to see the variation in letterbox design and to photograph some for display and discussion. Notice any that have a narrow letter slot which makes it difficult to fit larger sizes of letter mail.

#### Session 2

This session is about using accurate measures in designing and creating a cardboard letterbox, and being able to explain the process, using a flow diagram.

SLOs:

• Use standard measures of length to design and make a letterbox.
• Use a simple flow diagram to record the design process, including using appropriate symbols and abbreviations for length measurements.

Activity 1

Start by discussing letterbox photographs taken on the walk, noting functional design features, and individual ‘quirky’ features which give some character.
Display and discuss again the optimum agreed range of letterbox measurements from Session 1.

Activity 2

Make pencils and paper available.
Have students draw their own letterbox design diagram, including the measurements of the box, the slot, and any additional features, for example, an aperture for a newspaper (as shown in Attachment 1).

Activity 3

When designs with indicative measurements are accurately completed, make construction materials and rulers available to the students.
Review key teaching points associated with these skills*, emphasising the importance of making accurate measurements.
Give time for letterboxes to be constructed. Make paint and other construction material available as desired/needed. ‘Quirky’ features can be added once basic construction is completed.
The last task is for students to paint (or create) their letterbox number, choosing a favourite number. Should two students choose the same number, for example 10, have them use 10a, 10b and discuss why numbering actually works this way in building subdivisions, shared driveways etc.

Activity 4

As students complete their construction, they should record the process in the first three stages of their own design flow diagram including drawings showing measurements, and annotations. For example:

Activity 5

Have student suggest how their design might be tested. Agree that they could position their boxes in a suitable classroom space, list their addresses, (name and letterbox number) write letters to each other, place them in used envelopes and post them into the appropriate box. The width of the slit, size of the box and ease of opening can be evaluated by seeking feedback from classmate users.

#### Session 3

This session is about investigating the effect of email on the volume of letter mail over time.

SLOs:

• Pose an investigative question.
• Plan a questionnaire.
• Gather data.

Activity 1

Once again, begin by reading school intranet messages. Reread the mail brainstorm from Session 1. Explain that people haven’t always had computers and email, but that they used to rely on letter mail for their messages. (‘email’ was introduced internationally c. 1993.)
Ask: “Does anyone have an “I wonder” about email and letter mail.”
After discussion, agree on a worthwhile investigation; for example: investigating whether the increase in the use of electronic mail means that people are now getting less letter mail than they did x years ago. (suggest 5 to 10 years ago: a time period that is meaningful to the students.)

Activity 2

Have students suggest an investigative question. For example: ‘Has the amount of letter mail our parents/families are getting in their letterboxes changed in the last 5 years?’

Activity 3

Have students discuss and design in pairs how the data could be collected.
Have students share their ideas.
Discuss and agree to a simple (class) data gathering process such as:
Each student in the class will ask at least one parent/caregiver and one grandparent /aunt/uncle to complete a questionnaire (paper copy or on school/class blog) asking:

Activity 4

Have students complete preparations for gathering the data, including setting a realistic response time for participants.

#### Session 4

This session is about sorting and creating an effective data display, and answering the investigative question.

SLOs:

• Sort and display findings.
• Consider the results of the findings.

Activity 1

Explain that the questionnaires are ready for analysis. As a class, discuss what this means and have students describe the process and purpose of analysing and presenting information. Agree that one way to present information is to use a bar graph. Review the features of a bar graph, highlighting key teaching points.** (see Description of the mathematics, p1.)

Activity 2

Make available a copy of each questionnaire response, one copy of the blank questionnaire for each student to record results, graph paper and pencils.
Explain that each of the questionnaire responses will be read aloud.
Each student should listen and record the results on the blank form, using tally marks.
Have a student model this and discuss. For example:

Activity 3

When all students have completed their tally charts, together, discuss the data values, the label and the scale for each axis on the graph, and possible titles for the display.

1. Create you own data display (graph) for these data.
2. Write your own answer to the investigative question. (In this case: ‘Has the amount of letter mail our parents/families are getting in their letterboxes changed in the last 5 years?’)

#### Session 5

This session is about presenting findings and reflecting on the investigative process.

SLOs:

• Present findings.
• Explain how technology both reflects and changes society and the environment and increases people’s capability.

Activity 1

Have students present their completed display and findings to a partner. Have students explain their partner’s work and ideas to the class.

Activity 2

Discuss task 2: Answer to the question (from Session 4, Activity 3)
Read aloud and discuss the questionnaire responses that give reasons for this.

Activity 3

Discuss task 3: If there are changes, think how these might affect people (from Session 4, Activity 3)
Consider posties/other mail workers, the reduction in the volume of Christmas cards sent, the increase of online shopping and courier deliveries.

Activity 4

Also ask and record student responses as appropriate:

• How effective was our questionnaire? (Did we ask the right questions? Should we have asked them in another way?)
• Can we say that what we have found out is true for all of our city or our country? (No, we haven’t asked enough people.)
• Is there another investigative question you want to ask now?
• Do you think your family will have a letterbox in 10 years? Why do you think this?

Activity 5

Share letterbox flow diagrams and discuss Part 4: Test and improve.

Have students reflect on the use the letterboxes have had to this point in time, consider any improvements, and complete this section. Have them display their diagrams with their letterboxes.

Activity 6

Reflect on learning in this unit of work. Highlight the measurement skills and statistics skills that have been learned and applied, and recognise the importance of the technology design process.

Attachments