Put a blunt pencil beside an intact manual sharpener and ask, “What must we put in, and what must someone do?” Your students might name the pencil, cutter and casing straight away. The challenge is getting beyond that parts list to explain how the parts, actions and results are connected.
Separate the pencil from the turning action
Start two entries on the board:
- Material input: the pencil
- Energy supplied by a person: turning the pencil or handle
The pencil is the material being changed. It doesn’t supply the energy that operates the sharpener. The person supplies energy by turning the pencil or handle. Ask, “If the pencil is in place but nobody turns anything, what is missing?” The material is there, but no one is supplying energy through the operating action.
This distinction helps students describe relationships among inputs, processes and outputs, which is central to the account of systems in ACARA’s systems guidance. Energy isn’t limited to electricity, and force isn’t itself a form of energy. Explain the transfer in words; no calculation is needed. The Victorian Department of Education’s energy guidance offers useful background for making those distinctions.
Watch what moves and what changes
Operate the sharpener while students watch. Keep it intact, follow its instructions and your school procedures, and don’t let students touch the blade, reach into openings or dismantle the tool. Choose a model whose shavings can be viewed safely.
Match your explanation to the sharpener in front of you. In a simple fixed-blade model, the pencil turns against the cutter. A crank sharpener may work differently, so check its operation before describing what moves. If the cutter is hidden, separate what students can actually see from the general explanation that cutting removes pencil material.
Give the material and energy separate arrows
Draw this material pathway:
Pencil → material removed by the cutter → sharpened pencil + shavings
Add a separate arrow pointing into the cutting step and label it Person supplies energy by turning. Draw the person outside the sequence, with their energy arrow pointing to the cutting step. A labelled representation can make a system’s workings and relationships clearer, as described in ACARA’s guidance on models and systems.
Keep the shavings in the pathway even if they stay inside the casing. They’re a material result of sharpening. This diagram accounts for the main material changes; it isn’t a complete audit of every energy transfer.
Turn the labels into an explanation
Model a connected response: “The pencil is the material being changed. The person supplies energy by turning. Movement between the pencil and cutter removes material to make a point. The results are a sharpened pencil and shavings.”
Then ask students to connect one relationship with because: “The pencil becomes pointed because the cutter removes material as the pencil and cutter move against each other.” That explains much more than “pencil, blade, handle”. If the shavings disappear from a student’s account, ask where the removed material went. If electricity appears, return to the action that operates this particular tool. Shavings are waste material, but their presence doesn’t measure wasted energy or efficiency.
Try the explanation on a hole punch
Use an intact manual hole punch as a second teacher-operated example, keeping fingers clear of the mechanism. The paper is the material input. The person transfers energy by pressing. The punch cuts the paper, producing a sheet with holes and removed paper circles.
Ask what stays the same and what changes across the two systems. Both need material and energy supplied through a person’s action, but the actions, cutting processes and intended results differ. Students might write, “Paper circles are produced because the punch cuts those pieces out of the sheet.”
Use it before further systems work
This demonstration revisits earlier learning about forces and product function while students practise explaining relationships with technical language and graphics. The Years 5–6 content sequence shows that AC9TDE6K02 specifically concerns electrical energy changing into movement, sound or light. This manual activity prepares students to explain systems, but it doesn’t fully address that descriptor or the complete generate-and-iterate work in AC9TDE6P02.
Build on the explanation in a wider unit
For broader work with designed systems, the product description for the Smart Systems Unit - Years 5-6 lists “Identify and explain inputs, components, processes and outputs in designed systems”. These two demonstrations are separate from the unit.
Finish with one short explanation
Return to the hole punch and ask: “Name the material, explain how the person supplies energy, describe what changes, and account for both material results. Connect one part of your explanation with because.” If energy is unclear, revisit the pressing action. If the circles are missing, trace the removed material. If students give labels alone, model another causal sentence.