Year 7 Science · Unit 4 · Lesson 15
Master Worksheet
Learning Goals
Extension · optional
This extension goes beyond the Stage 4 syllabus dot points. The Sun’s layers, sunspots, solar flares and how it makes energy by nuclear fusion go further than Year 7 asks for; nuclear fusion comes back in Year 10 Reactions. Nothing on this sheet is assessed in Year 7, so it is enrichment: do it if you are interested.
1. Name the Sun’s three main layers in order, starting from the centre.
Find the error
Ruby wrote this fact sheet
(1) The Sun is the largest planet in our Solar System. (2) It makes its energy by burning hydrogen, like a gas stove. (3) The photosphere is the bright surface we see from Earth. (4) The corona is the Sun’s hot centre, where its energy is made.
2. Three of Ruby’s sentences contain an error. For each one, give the sentence number and the correct science.
3. Sunspots look dark, yet they are extremely hot. Explain how both of these can be true.
4. The Sun and the stars at night are all stars. Explain why the Sun looks like a huge bright disc while the others look like tiny dots.
Read the data: flares and southern lights
Scenario
A science club in Hobart kept records of four solar flares. For each one, they noted whether they saw the aurora australis that night and whether local radio signals were disturbed.
| Event | Size of flare | Aurora seen from Hobart? | Radio signals disturbed? |
|---|---|---|---|
| 1 | big | Yes, a bright glow | Yes |
| 2 | small | No | No |
| 3 | big | No: the sky was cloudy all night | Yes |
| 4 | medium | Yes, a faint glow | No |
Source: made-up records for this worksheet.
5. Describe the pattern between the size of a flare and its effects on Earth. Use Events 1, 2 and 4.
6. A club member concludes: “No aurora was seen in Event 3, so that flare sent no particles to Earth.” Use Table 1 to evaluate this conclusion.
7. Evaluate this statement: “If you really want to study the Sun closely, the best way is to look at it through a powerful telescope.”
Question 1
Core, photosphere, corona. All three in the right order = 2; the right three in the wrong order = 1. [2 marks]
Find the error: Question 2
(1) The Sun is a star, not a planet (1). (2) It does not burn fuel; hydrogen joins to make helium by nuclear fusion (1). (4) The core is the centre where energy is made; the corona is the faint outer glow (1). Sentence 3 is correct. [3 marks]
Question 3
They are slightly cooler than the gas around them, so they look dark by comparison (1), but they are still extremely hot (1). [2 marks]
Question 4
The Sun is the closest star to Earth (1); the other stars are so far away that they look like tiny dots (1). [2 marks]
Read the data: Question 5
The bigger the flare, the stronger the effects (1): the big flare gave a bright aurora and radio problems, the medium one a faint aurora only, the small one neither (1). [2 marks]
Question 6
Not supported (1). Radio signals were disturbed, as after the other big flare, so strong activity did reach Earth (1). Cloud blocked the view: not seeing an aurora does not mean there was none (1). [3 marks]
Question 7
Marking guide: 1 judgement (disagree); 1 a telescope focuses the Sun’s light and can blind almost instantly; 1 damage happens in seconds and is not felt; 1 ordinary sunglasses do not block enough light; 1 scientists use special telescopes with strong filters; 1 a safe method: certified eclipse glasses, or a pinhole projector showing the Sun on a card. [6 marks]
Model answer: I disagree. A telescope focuses the Sun’s light and can blind you almost instantly, and the damage happens in seconds without you feeling it. Sunglasses do not help, as they are made for everyday brightness. Scientists use telescopes with strong filters. I would use a pinhole projector, which shows the Sun on a card.
Common error: treating “not seen” as “did not happen”.