Gwen frowned. She wasn't stupid. She knew that there was a fourth of July in every place on Earth that used that calendar. The difference was, hers was a holiday. She'd said that. "I meant Independence Day, sir," she corrected herself, managing to keep a scowl off of her face. "Sometimes we just call it that because that's the date it falls on."

Which didn't really make sense, now that she thought about it. Christmas was hardly ever called 'The Twenty Fifth of December.' Still, it was the way it was often referred to.

Why the earth had seasons? That was science. Gwen knew that stuff. She counted on her fingers, trying to choose the perfect five words to describe it. It was pretty hard. It was a ten-word explanation at least.

Finally she raised her hand, a little more tentative with this answer than she had been for the last. Now that her first answer had been sort of mocked, she wasn't sure if she wanted to answer a second, but the thing was, not all of these kids had gone to muggle school. They might not even know all of that stupid science stuff Gwen had learned there. "The Earth's axis tilts."

That was why they had seasons. While the earth rotated around the sun on a tilted axis, they would always have seasons. Depending on which part of the Earth a person was on. That was also the reason the poles were always cold. They didn't get as much sunlight as other parts of the planet.