This video uses a simple demonstration to explain why we have day and night and why days are longer in the summer and shorter in the winter in the northern hemisphere.

Earth’s axis of rotation is tilted, as you can see from this illustration. This means that day and night are not equal lengths in most places on the planet. As Earth moves through its orbit ...

Day length is a factor that fluctuates according to season and latitude. Many species, such as certain flies, adjust their circadian rhythm (daily activity cycle) to adapt to these variations in ...