Many people may sometimes wish it could be summer all year round. However, as nice as summer is, we really need the other seasons as well.
Then why do we have different seasons? We know that the Earthspinson its own axis (轴线). This makes day and night. In 24 hours the Earth turns round once. When we are facing the sun, it is day. When we face away, it is night. Simple!
We travel around the sun in a circle. So why does it get colder in winter and hotter in summer? It's because the axis of the Earth is tilted (倾斜的). It means that in summer some places, such as the UK, are leaning towards the ssun. The temperature rises. As the Earth travels around the sun, these places begin to tilt away and the temperature drops. It becomes winter.
This is why when the UK has winter, Australia has summer. Imagine having Christmas dinner on the beach! But not all countries have seasons. Countries near the equator (赤道), the line which goes round the middle of the Earth, don't have different seasons. The weather stays almost the same temperature all the year round. Can you think why this is? The middle doesn't tilt very much, does it? This means the seasons don't change much.
Then what about the North and South Pole? What are the seasons like there? Because they get very far away from the Sun, their seasons are very extreme. There are only two seasons near the North and South Pole: winter and summer. What's more, they only have one sunrise and one sunset a year. It is dark for six months of the year and light for six months of the year. What problems would there be if you had to live somewhere that was dark for six months of the year and light for six months of the year?
