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Australian primary science · Year 6 · Lesson 3 of 3
Tilt and the seasons
Inquiry question: Why are winter days in Hobart so much shorter than summer days, and why don’t Darwin’s days change much?
Check practical materials
Using a model
What students learn
Earth’s axis is tilted. As Earth travels around the Sun, first the Southern Hemisphere and then the Northern Hemisphere leans towards the Sun. This changes day length and how direct the sunlight is, which causes the seasons.
Success criteria
- I can show Earth’s tilt and revolution with a model.
- I can explain why summer days are longer and warmer.
- I can explain why seasons are not caused by distance from the Sun.
Preparation and materials
Before this lesson: Students can use the torch-and-ball model to show rotation (lesson 2).
- Small torch (the Sun), placed on a stack of books in the middle — 13 (one per pair)
- Orange or ball on a skewer, from lesson 2 — 13
- Stickers for Hobart and Darwin — 2 per pair
- String, about 1 m long (keeps the distance from the torch the same) — 13
- Grid paper (for the direct and slanted light test) — 13 sheets
- Optional: iPads with Bottlebrush Education — 13
- Darkened room — 1
Teacher setup
- Set up 13 spaces where a torch can sit in the middle of a desk or the floor.
- Tie one end of each string to the torch stack.
- Check torches work.
- Darken the room.
Safety and adaptations
- Carry skewers point-down and keep them away from faces.
- Never shine torches into anyone’s eyes.
- Never look directly at the Sun.
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 shine the torch straight down on grid paper, then at a slant, and count the squares lit each time.
- Tilt the axis, keep it pointing at the same wall, and move the ball to four positions around the torch on its string.
- At each position, spin the ball and compare how long Hobart and Darwin stay in the light.
- Compare with the day-length table.
- Optional: in Sun and shadows, compare Midsummer and Midwinter at 12 noon and find which times are night.
Teacher modelling prompt
Tilt the skewer so the South Pole leans towards the torch. Spin the ball slowly. Think aloud: “The Hobart sticker spends a long time in the light and a short time in the dark: long days. That’s our summer.” Then, keeping the skewer pointing at the same wall, walk the ball to the opposite side of the torch: “Now the South Pole leans away. Hobart spends longer in the dark: short winter days. And the string shows I’m the same distance away, so distance didn’t cause the change.”
Record and explain evidence
Recording question: How do tilt and revolution change day length and the seasons?
| Ball position | Which hemisphere leans towards the torch? | Season in Australia | Hobart: longer in light, dark or equal? | Darwin: longer in light, dark or equal? |
|---|---|---|---|---|
| ________________ | ________________ | ________________ | ________________ | ________________ |
Example recording headings; record actual observations, including inconclusive results.
Discussion prompt
Use the model and the puzzle fact to decide.
Provided example or reference data
Approximate day lengths, sunrise to sunset (rounded)
| Place | Midwinter (June) | Around 21 March or 23 September | Midsummer (December) |
|---|---|---|---|
| Darwin (near the equator) | about 11 hours | about 12 hours | about 13 hours |
| Hobart (far south) | about 9 hours | about 12 hours | about 15 hours |
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 causes the seasons?
Explain with evidence: Why do Hobart’s summer days last about 15 hours but its winter days only about 9 hours?
Apply the idea: It is December. Is it summer or winter in Japan (Northern Hemisphere)? Explain using tilt.
Teacher answer guidance and saved classroom work are available through the main lesson experience where supported.