We think of winter with cold weather and lack of daylight, summer with long warm evenings where the sun lingers in the sky. Such changes is part of the series of cycles which affect the Earth as it revolves around the Sun. Depending on the season, sunlight will shine on the poles 24 hours a day! In summer the North Pole has complete sunlight for 24 hours per day. In the winter the North Pole is in complete darkness 24 hours per day. These conditions last about 6 months per year. If the Earth were not tilted there would be equal amounts of sunlight and darkness around the world each day. Because of our tilt, this changes the hours of sunlight and darkness we experience. The tilt of the earth doesn’t just affect the amount of daylight reaching the earth’s surface. The sun provides not only light, but heat, so the presence or absence of direct sunlight affects seasonal temperatures. Long summer days brings hours of heat and energy to become absorbed by mountains, rivers, lakes and the ocean. Short wintry days means less heat and energy absorbed by the soils, rivers, lakes and ocean causing cooling and in some places it becomes freezing. Such seasonal changes can affect many organisms on earth – not just among humans .Absence of heat and light causes food supplies to decrease or go away, such as flowers dying in winter taking away food for bees and other insects, Darker days is also the cause of many of the mass seasonal migrations experienced across the animal kingdom. Certain species of mammals, fish and, most particularly, birds, respond to reduced daylight and heat by seeking out better environmental conditions, like longer, warmer days. Science Period 1 and 2 know how to explain why we know the Earth is tilted on its axis and why we have opposite seasons in the Northern Hemisphere compared to the Southern Hemisphere. Science Period 3 will be starting their Season Poster tomorrow.
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Mrs. TaylorI love science! Everything about the world is interesting and never boring. I love to study plants, animals, insects, and people. My favorite subjects are my students who are the most unique organisms on the planet! Categories |