He had heard about a well in Syene (now Aswan, Egypt) where at noon on the summer solstice (21st June), the sun would be directly overhead and so shine straight down the well, without casting any shadow. Then about 240 BC Eratosthenes devised an experiment to estimate the Earth’s circumference. The Ancient Greeks noticed that the shape of the Earth passing across the moon during a lunar eclipse was a crescent, which means the Earth has to be curved. It is not flat because if it was flat we would always be in daytime and in one season.Read this article from NASA which includes an answer to 'how do we know the earth is round?'.Īmazingly, we’ve known the Earth is round for over 2000 years. It is round, because we have day/night and season. No, because if the earth was flat we would always be in daytime, there would never be night time because the earth would never face away from the sun. If the earth was flat could we have day and night? When 1/2 of the Earth is facing away from the sun it is night. When 1/2 of the Earth is facing the sun it is day. We wouldn't because seasons are caused by the different hemispheres getting direct or indirect sunlight, so if the earth was flat the hemispheres would get the same amount of sunlight.ĭay and night are caused by Earth's rotation (spin) on its axis. If the world was flat how would we have seasons? Then Figure 3 would be winter in the north and summer in the south.įinally figure 4 would be spring in the north and fall in the south. Therefore figure 2 would be fall in the north and spring in the south because both hemispheres are getting equal sunlight. ~ We have different seasons because of the earths tilt (23.5) and revolution. ~ We have different seasons because of the earths tilt (23.5) and revolution around the sun.įor example on figure 1, the Northern Hemisphere is summer because it is getting hit with direct sunlight and in the Southern Hemisphere it is winter because it is getting indirect sunlight. Seasons occur when the suns rays hit the Earths surface directly or indirectly. ~ The Earth has four seasons (Winter, Spring, Summer, Fall)įirst lets look at what causes the seasons: _abc Powtoon Transcript Is the earth flat or round
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