Year 9 Science · Unit 2 · Lesson 02
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Learning Goals
Read the graph
Study the bar chart below, then answer the questions that follow.
Density of Common Engineering Materials
Data: Ashby, M.F. & Jones, D.R.H., Engineering Materials 1, 4th ed. (Elsevier, 2012); values are typical at 20 °C.
(a) Which material shown in the chart has the lowest density?
(b) An aircraft designer wants to build a wing that is as light as possible but still strong. She is comparing titanium and aluminium, both have similar tensile strength. Using the chart, which material should she choose? Justify your answer.
(c) Apart from its low density, suggest ONE other physical property reason why polyethylene is commonly used for food containers rather than steel.
Compare two
Complete the table to compare glass and steel as possible materials for building a bridge. Use lesson content and your own reasoning.
| Feature | Glass | Steel |
|---|---|---|
| Tensile strength | ||
| Hardness | ||
| Transparency | ||
| Density (g/cm³) | ||
| Thermal conductivity | ||
| Overall suitability for bridge construction |
1. A frying pan base is made from copper rather than wood. Use TWO specific physical properties from the lesson to explain why copper is the better choice for this purpose.
2. A window pane must allow light through and resist scratching from windblown grit. Name the TWO physical properties most relevant to these requirements and explain how glass satisfies them.
Wrap Up
In one sentence, what was the main idea of this lesson?