Reasons for Seasons

1) When it is winter in the Northern Hemisphere, the area between the equator and the Tropic of Capricorn gets the most concentrated light. In the summer, though, the area with the most concentrated light is between the equator and the Tropic of Cancer.

2) In the winter, the light halfway between the equator and the North Pole is a lot more spread out than in the summer, because the Northern Hemisphere is more tilted towards the Sun in the summer and so receives more direct sunlight.

3) If the squares on the acetate get larger (they are farther from the equator), it means that the same amount of light is reaching the other squares (near the equator), but since the squares are stretched out, the light has to be distributed and so less light reaches each area.

4) The Poles are consistently the coolest areas on the planet, because the only get light a very short time every year, in the summer, and even then the light is stretched out. The equator, on the other hand, barely has seasons, because it is so consistently receiving direct sunlight and heat. It is the closest place on Earth to the Sun.

      The equator always receives the same amount of light and heat, so there are no real seasons. The poles, on the other hand, are always dark in the winter and always light in the summer. They have no day or night, it's like winter is the night and summer the day. They don't have autumn or spring, just a very long winter and a very short summer.

5) The toothpick’s shadow will be longest in the summer and shortest in the winter.

6) If the square is more stretched, out, it’s because it’s at an angle (because the Earth is a sphere), which is exactly how the Sun’s rays work: the light is at an angle, so it is more stretched out.

7) Seasons define the temperature, weather and amount of light in different parts of the Earth. The Northern and Southern Hemispheres are on opposite ends of the Earth, and as a result are opposites in seasons. If it's summer in Europe, it's winter in Australia. This is because the Earth is not fully upright. It's tilted on an axis, at 23.5°. In the summer, our hemisphere is tilted towards the Sun, while the other is tilted away from it. This means that ours receives more heat, more light and longer days than the other. In spring and autumn, both Hemispheres receive the same amount of light and heat.