Year 7 Science · Unit 4 · Lesson 13
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Learning Goals
Fill the gap: how science moves forward
Choose words from the word bank. Each word is used at most once. Two words are not needed: cross them out.
Scientists build a better . This new tool makes new that were not possible before. Those observations build new , and they can even change the scientists use to explain the Universe. A telescope does not decide what is on its own. It gives scientists the they need to test and improve their ideas.
Order the James Webb mission
Number the events from 1 (first) to 5 (last).
| Order (1–5) | Event |
|---|---|
| Scientists use the images to learn how the earliest galaxies, stars and planets formed. | |
| The telescope slowly unfolds in space, like origami. | |
| The first full-colour images are released in July 2022. | |
| A rocket launches it from South America on 25 December 2021. | |
| Engineers fold the telescope up so that it fits inside a rocket. |
Cause and effect: seeing inside a dust cloud
Fill the two empty boxes. Each box is caused by the one before it, and row 2 carries on from the end of row 1.
1. Light takes time to travel across space. Explain why JWST seeing the most distant galaxies is also like looking back in time, and what this helps scientists learn.
Read the data: JWST’s parking spot
Scenario
JWST sits at a place called the second Lagrange point (L2), on the far side of Earth from the Sun. From there the Sun, Earth and Moon are all on one side of the telescope, so one sunshield keeps it cold enough to see in infrared. Table 1 compares some distances.
| Object | Distance from Earth (km) |
|---|---|
| The Moon | 384 000 |
| JWST at L2 | 1 500 000 |
| The Sun | 150 000 000 |
Source: JWST from Lesson 13; the Moon and the Sun are rounded standard values.
2. How many times further from Earth is JWST than the Moon? Round to the nearest whole number. Does your answer agree with the lesson?
Answer times
3. Tom says: “JWST is parked about halfway to the Sun, so it can get close to the Sun’s light.” Use Table 1 and the scenario to give two reasons why Tom is wrong. Show any working.
4. Choose either the first image of a black hole (2019) or the detection of gravitational waves (2015). Explain how it is a recent advance that increased our knowledge of the Universe, then compare it with JWST.
Fill the gap: how science moves forward
instrument; observations; knowledge; models; true; evidence. Not used: opinions, rockets.
Order the James Webb mission
Reading down the table as printed, the correct step numbers are 5, 3, 4, 2, 1. In order: folded to fit the rocket; launched 25 December 2021; unfolds in space; first images July 2022; scientists learn from the images.
Cause and effect: seeing inside a dust cloud
Box 1: infrared light passes through dust that blocks visible light (1). Box 2: so JWST can see inside dust clouds where new stars and planets are forming (1). [2 marks]
Question 1
Their light left them long ago, so we see them as they were then (1). This shows galaxies from soon after the Universe began, and how the first galaxies grew (1). [2 marks]
Question 2
1 500 000 ÷ 384 000 = 3.9 (1), so about 4 times; this agrees with the lesson’s “about four times further than the Moon” (1). [2 marks]
Question 3
Halfway would be 75 000 000 km, but JWST is only 1 500 000 km away, about 1/100 of the way (1). It is on the far side of Earth from the Sun, not between them (1). It is placed to stay cold behind its sunshield, not to get close to the Sun’s light (1). [3 marks]
Question 4
Marking guide: 1 instrument (EHT: radio telescopes worldwide joined as one; or LIGO detectors); 1 observation (dark centre ringed by glowing gas; or ripples in space from two black holes crashing); 1 knowledge (what a black hole really looks like, showing black holes are real; or a new way to observe events); 1 linked as a chain; 1 similarity (same chain as JWST); 1 difference (radio on the ground, or ripples not light, versus JWST’s infrared from space). [6 marks]
Model answer: In 2019 the Event Horizon Telescope joined radio telescopes around the world to act as one giant telescope. It observed a dark centre ringed by glowing gas, the first picture of a black hole. This gave new knowledge: for the first time scientists could see what a black hole looks like, showing black holes are real. Like JWST, a new instrument made a new observation that built new knowledge. Unlike JWST, it used radio telescopes on the ground, not infrared from space.
Common error: thinking JWST is close to the Sun; it is behind Earth, away from the Sun.