Work samples

Science

Year 8

Above satisfactory

Expansion in gases

Summary of task

Prior to the sample task, students had explored states of matter focusing on how the particle model explains matter in its different states at a molecular level. They had completed various inquiries relating to the particle model including kinaesthetic activities designed to help students visualise the structure of matter at the molecular level. Students had also investigated the differences between elements, compounds and mixtures at the particle level and had engaged in several activities that consolidated their understanding of the concept that matter consists of particles that are in continuous motion.

Students were asked to plan and develop an experiment that demonstrates expansion in a substance of their choice (solid, liquid or gas) and to relate their observations to the particle model. Students received and completed a worksheet that helped to guide them through their research and planning the investigation.

Students were asked to create a final report of their investigation in the form of a poster, presentation or word document. Independent of their choice of format, students were expected to follow the same scientific report structure, and were given explicit instructions on the sequence of headings to include. In their discussion, students were asked to describe and explain their results in terms of the particle model and to relate their findings to real-life situations.

Students were given four hours of class-time as well as time at home to complete their planning documents, perform the experiments, and seek help and feedback from teachers.

Achievement standard

By the end of Year 8, students compare physical and chemical changes and use the particle model to explain and predict the properties and behaviours of substances. They identify different forms of energy and describe how energy transfers and transformations cause change in simple systems. They compare processes of rock formation, including the timescales involved. They analyse the relationship between structure and function at cell, organ and body system levels. Students examine the different science knowledge used in occupations. They explain how evidence has led to an improved understanding of a scientific idea and describe situations in which scientists collaborated to generate solutions to contemporary problems. They reflect on implications of these solutions for different groups in society.

Students identify and construct questions and problems that they can investigate scientifically. They consider safety and ethics when planning investigations, including designing field or experimental methods. They identify variables to be changed, measured and controlled. Students construct representations of their data to reveal and analyse patterns and trends, and use these when justifying their conclusions. They explain how modifications to methods could improve the quality of their data and apply their own scientific knowledge and investigation findings to evaluate claims made by others. They use appropriate language and representations to communicate science ideas, methods and findings in a range of text types.

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Uses understanding of molecular kinetic theory to explain why gases expand and names relevant scientific law
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Considers ethical and safety concerns
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Identifies independent and dependent variables and describes in detail how they are measured
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Identifies variables that need to be controlled and demonstrates understanding of molecular kinetic theory by including number of molecules
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Uses reasoning based on molecular kinetic theory to support hypothesis

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Describes experimental procedure using clear step-by-step instructions
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Creates annotated diagram to illustrate experimental setup

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Displays results in table
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Creates column graph with appropriate axis titles and legend to display results

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Refers to evidence to support conclusion
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Suggests improvements to experimental method
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Reflects on learning and applies it to describe real-life situation
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States relevant scientific law
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Uses molecular kinetic theory to explain results

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Attempts to demonstrate Charles’s Law using correct mathematical approach

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Identifies and formulates investigable question
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Researches relationship between temperature and volume and records key information including relevant scientific law
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Analyses potential ethical and safety concerns

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Considers variables relevant to investigation
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Identifies independent variable and plans way to change it
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Identifies dependent variable and plans way to measure it
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Identifies key variable to be kept constant

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Uses scientific reasoning based on molecular kinetic theory to develop hypothesis
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Formulates aim and predicts outcome of investigation

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Considers possible external influences on fairness of test
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Describes in detail experimental challenges and how they have been solved