seegongsik
Grade 6 (age 11-12)

grade 6 Seasonal Changes

Spring, summer, autumn and winter do not come round because of the distance between Earth and the Sun. Earth travels around the Sun with its axis tilted about 23.5°, so the height of the midday Sun and the length of the day change through the year. In summer, when the Northern Hemisphere leans toward the Sun, the Sun climbs high, its light gathers on a small patch of ground and the days are long, so it is hot; in winter, leaning away, the Sun stays low, its light spreads out and the days are short, so it is cold. Change the month to see where Earth is in its orbit in each season, then press the season buttons to compare the height of the midday Sun in Seoul and how widely its light spreads.

Why do the seasons change?

6
🌍 Why the seasons change
①Earth travels around the Sun once a year with its axis tilted about 23.5°.
②The axis always points the same way, so depending on where Earth is in its orbit, the Northern Hemisphere leans either toward the Sun or away from it.
③When the Northern Hemisphere leans toward the Sun it is summer; when it leans away it is winter.
④Earth is actually closest to the Sun around January, so distance is not the cause of the seasons.

Sun height and the strength of sunlight

☀️ Sun height and the strength of sunlight
①When the Sun is high, the same amount of sunlight gathers on a small patch of ground and warms it more.
②When the Sun is low, the same sunlight spreads over a larger area and warms it less.
③In Seoul, midday sunlight in winter spreads over about twice the area it covers in summer.
④Summer days are also longer, so the ground gets sunlight for more hours.

What changes with the seasons

Why there are seasons
Tilted axis (about 23.5°) + revolution → changing seasons
Earth circles the Sun while tilted, and that gives us seasons.
What Sun height does
Higher Sun → light gathers on less ground, longer days → warmer
The higher the Sun, the more sunlight each patch of ground receives.
🍂 Changes through the seasons
①Spring: the Sun climbs higher, days get longer and it gets warmer.
②Summer: the Sun is highest and days are longest, so it is hottest.
③Autumn: the Sun gets lower, days get shorter and it cools down.
④Winter: the Sun is lowest and days are shortest, so it is coldest.
⑤The hottest weather comes in July and August, a little after the Sun is highest in June, because land and sea take time to warm up.
⑥The Southern Hemisphere has the opposite seasons.

Summary

What causes the seasons
Earth circling the Sun with its axis tilted about 23.5° → seasons
It is the tilt, not the distance.
🎯 Key points
①The seasons are caused by Earth revolving with a tilted axis.
②Summer: the Sun is high and days are long, so it is warm.
③Winter: the Sun is low and days are short, so it is cold.
④The Southern Hemisphere has the opposite seasons to the Northern Hemisphere.
⑤The distance between Earth and the Sun does not cause the seasons.

Examples and Unit Test

Example 1
What really causes the seasons? (changes in the distance between Earth and the Sun / the tilt of Earth's axis)
1
Earth travels around the Sun with its axis tilted about 23.5°.
2
Because of that tilt, the Sun's height and the day length change through the year, and the seasons change. Earth is closest to the Sun around January, so distance cannot be the cause.
▸ Earth revolves with its axis tilted.
Distance also cannot explain why it is summer in the Southern Hemisphere while it is winter in the north.
Example 2
How would you explain why summer is hot, using the height of the midday Sun and the day length?
1
In summer the midday Sun is high, so the same sunlight gathers on a small patch of ground and heats it more.
2
The days are also long, so the ground gets sunlight for longer.
▸ The Sun is high, so its light is concentrated, and the days are long, so it shines for longer.
Choose winter in the second picture: the sunlit ground becomes about twice as wide as in summer.
Unit-test style
Which statement about the changing seasons is correct?
①The seasons are caused by the distance between Earth and the Sun.
②In summer the midday Sun is high and the days are long.
③There would be seasons even if Earth's axis were not tilted.
④In winter the midday Sun is high.
⑤When it is summer in the Northern Hemisphere, it is also summer in the Southern Hemisphere.
▸ ② In summer the midday Sun is high and the days are long.
1
In summer the Sun is high, so its light gathers on less ground, and the days are long, so it is warm.
2
The seasons come from the tilted axis (①, ③), the winter Sun is low (④), and when the north has summer the south has winter (⑤).
← Previous
Photosynthesis
Next →
Weather Forecasting

Last updated