Year 7 Science · Unit 3 · Lesson 12
Challenge Worksheet
Learning Goals
Explain it to a Year 5 student
Imagine your Year 5 cousin is about to ride a roller coaster for the first time. They ask: "Why does the roller coaster keep going after the first big hill? Doesn't it need an engine?" Use the sentence starters below to explain the science clearly. Use real examples and avoid jargon — but you must use the terms gravitational potential energy and kinetic energy at least once each.
"The basic idea is that at the top of the first hill, the roller coaster has a special type of stored energy called..."
"When the roller coaster rushes down the hill, that stored energy changes into..."
"This is why the roller coaster doesn't need an engine after the first hill — it's a bit like when you..."
"One thing people often get confused about is thinking the energy disappears. But actually, at the end of the ride when the brakes come on, the energy turns into..."
1. Each hill on a roller coaster must be lower than the one before it. A student says: "That's because the roller coaster runs out of energy." A scientist says: "That's because energy is converted to other forms at each point." Who is correct? Explain the scientist's statement using the law of conservation of energy.
2. The Scenic Railway at Katoomba (Blue Mountains, NSW) is one of the steepest railway inclines in the world. It descends about 310 metres. A fully loaded carriage has a mass of roughly 10 000 kg. Thinking about gravitational potential energy (GPE = mass × g × height, where g ≈ 10 m/s²), explain qualitatively: (a) how much GPE the full carriage has at the top relative to the bottom, and (b) what happens to all that GPE as the carriage descends. Name at least three forms the energy is converted to.
Wrap Up
In one sentence, what was the main idea of this lesson?