An educational design explaining the seasons and how they relate to the Sun, the Earth, and the Earth’s tilt. Living in New Zealand, I especially wanted to show that whatever season it is in one hemisphere, it’s the opposite in the other hemisphere – I think Northern Hemispherians forget that a lot! (Christmas in summer, it’s pretty cool.)
Many people think the seasons are because of how close the Earth is to the Sun, but it’s actually about which hemisphere is facing the Sun and which is facing away.
Yes, the Earth’s orbit is not equal – it is an ellipse (oval) where the Sun is not at the centre. When the Earth is closest to the Sun (around 3rd January every year), it receives about 6.9% more energy than at the opposite time of year. However, our environment is much more affected by which hemisphere is facing towards the sun (creating the seasons). This extra energy is mostly absorbed by higher proportion of water in the southern hemisphere, which is facing the Sun (summer) at the time.
The Earth’s tilt is usually 23.4 degrees, but it can vary slightly.