Year 7 Science · Unit 2 · Lesson 1
Challenge Worksheet
Learning Goals
What if…?
Scenario
The Moon's gravitational pull is about one-sixth that of Earth's (roughly 1.6 m/s² compared with Earth's 9.8 m/s²). Scientists at the Australian Space Agency are planning a future Moon base. They need to store water (for drinking), oxygen gas (for breathing), and iron tools. A science student reads about this and wonders: "If gravity is weaker on the Moon, does that change whether something is a solid, liquid or gas? Does mass change? Does anything about matter itself change?"
Using what you know from this lesson, predict and explain what would happen to the states of matter and to mass versus weight in this Moon-base scenario. Address at least three of the following in your answer: (1) whether water would still be liquid, (2) whether oxygen gas would behave differently, (3) whether the iron tools would weigh the same, (4) whether the mass of any substance changes on the Moon.
1. A student argues: "Plasma can't be a state of matter because it doesn't have a fixed shape or volume — that just makes it a gas." Use evidence from the lesson to either support or refute this argument.
2. Imagine you are writing a science guide for astronauts heading to Mars (gravity = 3.7 m/s²). In 3–4 sentences, explain why knowing the difference between mass and weight is critical for calculating how much fuel, food and water to load onto the spacecraft.
Wrap Up
In one sentence, what was the main idea of this lesson?