Year 9 Science · Unit 3 · Lesson 6
Challenge Worksheet
Learning Goals
What if…?
Scenario
In 2025, the Australian Energy Market Operator (AEMO) proposes a radical change: all energy measurements in Australia will switch from joules and kilowatt-hours to the calorie (1 calorie = 4.18 joules). This would affect electricity billing, nutrition labels, engineering specifications, and medical equipment. Your task is to think through what this change would actually mean in practice.
Using what you know from this lesson about energy units (joules, watts, kilowatt-hours), predict and explain what the practical consequences of this switch would be for three of the following areas: (i) electricity billing for Australian households, (ii) mechanical engineering and construction, (iii) medical nutrition and dietetics, (iv) physics education in schools. Use scientific terms in your answer.
1. The International System of Units (SI) uses joules for energy worldwide. Explain why scientists value having one agreed standard unit for energy rather than different units for different fields. In your answer, reference at least two situations where units must be converted between fields.
2. A student claims: "Power and energy are the same thing, a machine with more watts has more energy." Construct a clear counter-argument using definitions, formulas, and a specific numerical example involving an Australian appliance.
Wrap Up
In one sentence, what was the main idea of this lesson?