Year 7 Science · Unit 4 · Lesson 13
Master Worksheet
Learning Goals
Odd one out
In each set, circle the odd one out using the rule given, and write the reason. There is one answer in each set.
| Rule, then circle the odd one out | Reason for your choice |
|---|---|
| 1. The kind of light it collects: Parkes (Murriyang) · SKA-Low · Event Horizon Telescope · a telescope from 100 years ago | |
| 2. What it detects: JWST · LIGO · Parkes (Murriyang) · Event Horizon Telescope | |
| 3. Where it works: SKA-Low · Event Horizon Telescope · JWST · Parkes (Murriyang) |
Find the error
Kai wrote this summary
(1) The James Webb Space Telescope was launched in July 2022. (2) It sees in ultraviolet light, which can pass through dust. (3) It sits about 1.5 million km from Earth, about four times further away than the Moon. (4) Because it is so powerful, JWST decides what is true about the Universe.
1. Three of Kai’s sentences contain an error. For each one, give the sentence number and the correct science.
2. For hundreds of years, telescopes sat on the ground and collected only visible light. JWST changed two things about this. Name both changes, and explain what each one lets scientists see or do.
Read the data: the air on other worlds
Scenario
When an exoplanet passes in front of its star, some starlight shines through the planet’s air. JWST reads that light to work out which gases are in the air. A team pointed JWST at four exoplanets. Table 1 shows their results.
| Exoplanet | Passes in front of its star, as seen from JWST? | Gases found in its air |
|---|---|---|
| P | Yes | carbon dioxide, water vapour |
| Q | Yes | hydrogen, helium |
| R | No | no reading taken |
| S | Yes | no gases found |
Source: made-up results for this worksheet.
3. Explain why the team could not take a reading of the air on Planet R.
4. A student writes: “Planet S has no air at all.” Is this an observation or an inference? Suggest another explanation for the result, and one way scientists could find out more.
5. Evaluate this claim: “Now that we have space telescopes like JWST, Australia’s radio telescopes on the ground are no longer needed.”
Odd one out
1. The telescope from 100 years ago: it collected only visible light; the others collect radio waves (1). 2. LIGO: it detects ripples in space (gravitational waves); the others collect light (1). 3. JWST: it works in space; the others are on the ground (1). [3 marks]
Find the error: Question 1
(1) Launched in December 2021; July 2022 was the first images (1). (2) It sees infrared light, not ultraviolet (1). (4) JWST gives evidence; scientists use it to test and improve ideas (1). Sentence 3 is correct. [3 marks]
Question 2
It sees infrared, not visible light (1), which passes through dust, so it sees inside dust clouds and the most distant galaxies (1). It sits far out in space, about 1.5 million km away, where it stays cold and steady for clear infrared pictures (1). [3 marks]
Read the data: Question 3
JWST reads starlight that shines through a planet’s air as the planet passes in front of its star (1). Planet R does not pass in front of its star as seen from JWST, so no starlight passes through its air towards JWST (1). [2 marks]
Question 4
An inference; the observation is only “no gases found” (1). Another explanation: it has air, but too little or too faint for JWST to detect (1). Find out more: repeat the observations, or use a better future instrument (1). [3 marks]
Question 5
Marking guide: 1 judgement (disagree); 1 JWST collects infrared from space, radio telescopes collect radio waves, another kind of light our eyes cannot see; 1 different instruments give a fuller picture; 1 Parkes (Murriyang) and SKA-Low named; 1 remote, quiet areas far from city radio signals suit radio telescopes; 1 evidence: the first black hole image (2019) came from radio telescopes joined as the Event Horizon Telescope. [6 marks]
Model answer: I disagree. JWST collects infrared from space, but radio telescopes collect radio waves, a different kind of light, so together they give a fuller picture. Australia leads in radio astronomy with Parkes (Murriyang) and SKA-Low, because its remote areas are quiet, far from city radio signals. The first image of a black hole came from radio telescopes joined as the Event Horizon Telescope.
Common error: treating “no gases found” as proof of no air.