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Australian primary science · Year 6 · Lesson 2 of 3
An Aussie invention
Inquiry question: How did scientists working together make solar cells better?
Marked no materials needed
Pattern seeking
What students learn
Solar cells transform only part of the light energy that hits them into electrical energy. Over 70 years, scientists in many countries, including a team at the University of New South Wales, built on each other’s work to make cells that transform more of the light.
Success criteria
- I can explain what solar cell efficiency means.
- I can describe the pattern in efficiency over time.
- I can explain how the UNSW team built on others’ work, and how others built on theirs.
Preparation and materials
Before this lesson: Students know that solar panels transform light energy into electrical energy (lesson 1).
- One screen or projector to show this lesson’s student view (the solar cell timeline and data) (or print one student view per pair) — 1
- Workbooks or scrap paper, and pencils — 26
Teacher setup
- Open this lesson’s student view (the solar cell timeline and data) on your screen, or print the student view if the internet is unreliable.
- No other preparation is needed.
Safety and adaptations
Follow school science and equipment risk assessment procedures for the materials used.
Review your school policies and curriculum requirements before teaching.
How to investigate
The lesson sequence should leave pupils with evidence to interpret, not only an activity to finish.
- Pairs read the solar cell timeline and data in the student view.
- Describe the pattern in efficiency over time. Did it improve quickly or slowly?
- For each step, write whose work it built on.
- Explain in your own words what “20% efficient” means, using the words light energy, electrical energy and heat.
- Discuss: why did it take factories, not just the lab, for PERC cells to end up on roofs?
Teacher modelling prompt
Point to the first two rows. Think aloud: “1954: about 6% efficient. So out of every 100 units of light energy, about 6 became electrical energy and 94 were lost, mostly as heat. 1985: about 20%. That’s more than three times better. I’ll check whether it keeps going up.”
Record and explain evidence
Recording question: How did scientists working together make solar cells better?
| Year | Who | What they did | Efficiency (about) | Whose work they built on |
|---|---|---|---|---|
| ________________ | ________________ | ________________ | ________________ | ________________ |
Example recording headings; record actual observations, including inconclusive results.
Discussion prompt
What does the timeline show about how science and technology advance?
Provided example or reference data
Best silicon solar cell efficiencies in the lab (rounded, approximate values)
| Year | Who | Efficiency (about) |
|---|---|---|
| 1954 | Bell Laboratories, USA: first practical silicon solar cell | 6% |
| 1985 | UNSW team, Sydney: first silicon cell above 20% | 20% |
| 1989 | UNSW team: PERC cell reported | 23% |
| 1999 | UNSW team: PERL cell, a world record for many years | 25% |
| About 2020 | Factories around the world: most solar cells made use the PERC design | Factory panels about 20% |
Check the data source in the teacher lesson. Illustrative or fictional data are not measurements collected by your class.
Check understanding
What should pupils know? What does it mean if a solar cell is 25% efficient?
Explain with evidence: Explain how the PERC cell reduced wasted energy.
Apply the idea: Give two examples from the timeline of people building on others’ work. Stretch (older students): why do you think scientists publish their results instead of keeping them secret?
Teacher answer guidance and saved classroom work are available through the main lesson experience where supported.