Year 8 Science · Unit 2 · Lesson 17
Challenge Worksheet
Learning Goals
Explain it to a Year 5 student
Imagine your younger cousin has never heard of allotropes. Use the sentence starters below to explain why carbon can be both the hardest natural material AND a soft greasy pencil material, despite being the same element. Write at least two lines for each starter.
"Carbon atoms can arrange themselves in different ways, one arrangement is..."
"In diamond, the atoms are arranged so that..."
"In graphite, the layers of carbon atoms can..."
"The surprising thing is that..."
1. Graphite conducts electricity, which makes it useful as an electrode in batteries and industrial processes. Diamond, however, is an electrical insulator and is used in cutting tools and drill bits. A student says: "They are just different because one is natural and one is man-made." Identify the mistake in the student's reasoning and provide a scientifically accurate explanation for why diamond and graphite have such different properties and uses.
2. The five elements studied in this lesson, copper (Cu), aluminium (Al), helium (He), silicon (Si), and carbon (C), are central to a huge proportion of modern technology. Is this because they are among the most common elements in nature, or because they have uniquely useful properties? Justify your answer with specific evidence for at least three of the five elements.
Wrap Up
In one sentence, what was the main idea of this lesson?