Seasons, day length and the light year
The Earth's tilt, not its distance from the Sun, is why summer days are long and warm while winter days are short and cold.
Part of your national curriculum
- Physics: space physics: Understand the seasons and the Earth's tilt, day length at different times of year, and the light year as a unit of astronomical distance
Lesson overview
What you'll learn in this lesson
Understand the seasons and the Earth's tilt, day length at different times of year, and the light year as a unit of astronomical distance
Key learning points
- • Earth's tilt and the seasons
- • Day length through the year
- • The light year
This lesson at a glance
- 26 minutes
- 17 parts to scroll through
- 3 quick checks
- Marked quiz at the end
- Gentle pace: short sittings with pauses
Words to know
Scroll down — the lesson carries on below
Watch & discover
Part 1 of 17
Visual introductionPicture this
Seasons, day length and the light year
The Earth's tilt, not its distance from the Sun, is why summer days are long and warm while winter days are short and cold.
In a nutshell
Understand the seasons and the Earth's tilt, day length at different times of year, and the light year as a unit of astronomical distance
Learning cycle
Part 2 of 17
Learning cycle 1 of 2
Part 1 · Earth's tilt and the seasons
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 3 of 17
Learn
Earth's tilt and the seasons
Earth's axis is tilted at about 23.5° from vertical. As Earth orbits the Sun over a year, this tilt means different hemispheres lean towards or away from the Sun at different times, causing the seasons — not changes in distance from the Sun.
Reset break
Part 4 of 17
Pause
That's sitting 1 of 4 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Explore the idea
Part 5 of 17
Learn
Day length through the year
When the Northern Hemisphere is tilted towards the Sun (summer), it receives more direct sunlight for longer, giving long days and short nights. In winter, tilted away from the Sun, days are short with more indirect, weaker sunlight.
Quick check
Part 6 of 17
Quick check
Part 7 of 17
Reset break
Part 8 of 17
Pause
That's sitting 2 of 4 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Learning cycle
Part 9 of 17
Learning cycle 2 of 2
Part 2 · The light year
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 10 of 17
Learn
The light year
A light year is the distance light travels in one year — about 9.46 trillion kilometres. It is used to measure vast astronomical distances because using kilometres would produce impossibly large numbers; the nearest star beyond the Sun is over 4 light years away.
Quick check
Part 11 of 17
Reset break
Part 12 of 17
Pause
That's sitting 3 of 4 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Challenge round
Part 13 of 17
Game · Sort it
Which of these are true?
Drag each card into the right column. Tap a card first if dragging is fiddly.
True
Not true
Challenge round
Part 14 of 17
Game · Fill the gaps
Finish the sentences
Choose the word that belongs in each gap.
As Earth orbits the Sun over a year, this tilt means different hemispheres lean towards or away from the Sun at different times, causing the ____ — not changes in distance from the Sun.
A light year is the ____ light travels in one year — about 9.46 trillion kilometres.
It is used to measure vast ____ distances because using kilometres would produce impossibly large numbers; the nearest star beyond the Sun is over 4 light years away.
Challenge round
Part 15 of 17
Game · Recall cards
What mainly causes the seasons on Earth?
Card 1 of 3
Mastery quiz
Part 16 of 17
Marked quiz
End of lesson quiz: Seasons, day length and the light year
3 questions, marked with the reasoning shown. No timer.
1. What mainly causes the seasons on Earth?
2. What is a light year a measure of?
3. During Northern Hemisphere summer, why are days longer?
Lesson round-up
Part 17 of 17
Lesson round-up
Ready when you are
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Ask LunaPart 1 of 17 · Watch & discover
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Understand the seasons and the Earth's tilt, day length at different times of year, and the light year as a unit of astronomical distance