You're here because you want to firm up your understanding of the causes of the seasons on planet Earth, which is also tied in with the causes of day and night. It's a great place to test out your understanding of these important factors that govern our lives.
So, let's start with day and night. Fortunately, that's pretty straightforward.
Have a look at this diagram:
You can see a clear line, top to bottom, through the Earth, with the right-hand side being lit by the Sun - this, of course, is day time.
If you look carefully, you can see that much of North America is in darkness (night time). That's because the Sun's light is being blocked by the other side of the Earth. Can you think about why night-time temperatures are generally lower than daytime?
Now, if the Earth stayed like that, one side would be in permanent darkness and the other side in permanent light. Of course, it's not like that! The Earth spins on its (imaginary) axis, making one complete revolution every 24 hours (i.e. one day).
However, while it's spinning, it's also on a long journey around our star - the Sun. That journey (or orbit) takes 365.25 days - what we call a year. As you know, those 0.25 (1/4) days are made up, every four years, into what we call a leap year when we have an extra day (Feb. 29) and, so, 366 days in that year.
That annual orbiting of the Sun has another consequence - our seasons. Extraordinarily enough, our planet is tilted over at an angle of 24o, and this means that our two hemispheres (Northern and Southern) get a chance to spend a greater or lesser part of that year's orbit in the Sun's light and warmth.
In this diagram, you can see that the Earth on the left has the Northern Hemisphere angled towards the Sun. This means that, for every spin, that half of the Earth spends more time experiencing the Sun's rays compared to the Southern Hemisphere. So, that's our summer - longer days and so, as a result, more light and warmth. Makes sense really!
By the time the Earth has moved on 6 months, to the right-hand side of the diagram, the situation is completely reversed. Now, it's the Southern Hemisphere that is angled towards the Sun (their summer) and we in the UK have longer nights than days and, consequently, less warmth - winter time.
Think of it another way:
When the Sun is directly overhead in the summer (left-hand diagram), each ray of sunshine is more concentrated - it falls on a smaller area of the Earth's surface, focusing the heat and making it warmer.
Compare that to winter (right-hand diagram). Now, that same ray of sunshine is spread out over a larger area, so less concentrated heat and, consequently, each area of the Earth's surface under that ray gets less heat.
So, quite a lot to digest (hopefully you know a fair amount of this already) and before you tackle the questions, how about a brief scan over that introduction once more, to make sure you've got it nailed?