Year 7 Science · Unit 4 · Lesson 15
Foundation 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.
Match each term to its meaning
Write the letter of the correct meaning next to each term. Each letter is used once.
| Term | Letter | Meaning |
|---|---|---|
| Plasma | A. The faint outer glow, seen during a total solar eclipse | |
| Core | B. Gas so hot that it glows brightly | |
| Photosphere | C. A dark patch on the Sun that is slightly cooler than the gas around it | |
| Corona | D. The hot centre of the Sun, where its energy is made | |
| Sunspot | E. Joining hydrogen into helium, which releases energy | |
| Nuclear fusion | F. The bright surface of the Sun that we see from Earth |
True or false? Fix the false ones
Circle T or F. If a statement is false, correct it on the line.
1. The Sun is a star, and it is the closest star to Earth.
Correct it:
2. The Sun is a solid ball of rock, just like Earth.
Correct it:
3. Sunspots look dark because they are holes in the Sun.
Correct it:
4. The Sun makes its energy by joining hydrogen into helium deep in its core.
Correct it:
5. The Sun is by far the largest object in our Solar System.
Correct it:
1. Draw a large circle for the Sun. Label its three layers: core, photosphere and corona. Add an arrow to show the way energy moves.
2. We usually cannot see the corona. Explain why, and why it becomes visible during a total solar eclipse.
Read the data: Sun fact file
Fact file
Mia says: “The Sun is a giant campfire burning wood and coal, so one day soon it will burn out.” Use Table 1 to check her idea.
| Fact | Detail |
|---|---|
| What it is | A star: a giant ball of hot glowing gas (plasma) |
| Size | About 1.3 million Earths could fit inside it |
| How it makes energy | Joining hydrogen into helium (nuclear fusion) in its core |
| Fuel left | Plenty of hydrogen |
| Age | About 4.6 billion years, which is middle-aged for a star |
Source: facts from Lesson 15.
3. The Sun is called middle-aged. Use Table 1 to explain what this tells us about how much longer it will shine.
4. Use two facts from Table 1 to explain why Mia is wrong.
5. Write the most important safety rule about the Sun, and explain why it matters.
6. The Sun has been called “the engine that powers life on our planet”. Explain why.
Match each term to its meaning
Plasma → B; Core → D; Photosphere → F; Corona → A; Sunspot → C; Nuclear fusion → E.
True or false
1. True. 2. False: it is a giant ball of hot glowing gas (plasma). 3. False: they are slightly cooler than the gas around them, though still very hot. 4. True. 5. True.
Question 1
Core labelled at the centre (1); photosphere as the bright surface (1); corona as a faint glow outside the surface, and an arrow pointing outward from the core (1). [3 marks]
Question 2
The bright photosphere outshines the faint corona (1). In a total solar eclipse the Moon covers the photosphere, so the corona can be seen (1). [2 marks]
Read the data: Question 3
It is about 4.6 billion years old and only halfway through its life (1), with plenty of hydrogen left, so it will shine for billions of years more (1). [2 marks]
Question 4
The Sun does not burn wood or coal; it joins hydrogen into helium by nuclear fusion (1). It has plenty of hydrogen left (1), and has already shone for 4.6 billion years, far longer than any fire, so it will not burn out soon (1). [3 marks]
Question 5
Never look directly at the Sun, especially through binoculars or a telescope (1). Its light can permanently damage your eyes in seconds, without you feeling it (1). [2 marks]
Question 6
Marking guide: 1 a star whose energy is made in its core by nuclear fusion; 1 it gives almost all Earth’s light and heat; 1 the warmth keeps Earth fit for life; 1 plants use sunlight to grow, and that food feeds nearly every living thing; 1 solar panels on rooftops or solar farms. [5 marks]
Model answer: The Sun is a star that makes energy by nuclear fusion in its core. It gives Earth almost all its light and heat, which keeps the planet warm enough for life. Plants use sunlight to grow, and that food feeds nearly every living thing. In Australia we also capture its energy with rooftop solar panels.
Common error: saying the Sun “burns” fuel like a fire.