Day & NightAs we know from our study about the solar system, the planets orbit the Sun. The time taken for a planet to make a complete orbit or cycle around the Sun is called a revolution. The planets also orbit on their axis; a complete spin on a planet's axis is called a rotation.
The Earth takes 365 1/4 days to complete 1 revolution around the Sun and 24 hours to complete a rotation on its axis. The Earth is also tilted at an angle of 23 1/2 degrees. This rotation on its axis produces day and night. This is because as the Earth rotates on its axis, one side faces the Sun whilst the other faces away from the Sun. This means that on one side there is light (day) and the other is in darkness (night)
Phases of the MoonWhen we look at the sky in various nights we see that the Moon tends to be changing shape. This change in shape is due to the position of the moon relative to the Sun. Therefore at various positions the moon receives different amounts of sun light. We say that these are the PHASES of the Moon.
The LUNAR CYCLE starts with the NEW MOON, on the night of the new moon there is no moon to be seen in the sky. The Moon then starts to wax or grow and we see THE WAXING CRESCENT, FIRST QUARTER, WAXING GIBBOUS then comes the FULL MOON, this is the entire illuminated part of the Moon which is seen from Earth. The Moon then seems to start shirking or waning. The phases which are observed after the full moon are: WANING GIBBOUS, LAST QUARTER, WANING CRESCENT; the cycle is then started back to the NEW MOON
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Uneven Solar (Light) Distribution - SeasonsDue to the Earth's tilt of 23 1/2 degrees. The light which reaches the Earth is unevenly distributed on its surface. This leads to the varying hours of day and night on the Earth's surface as well as the formation of seasons.
The Southern hemisphere receives the most amount of sunlight. The areas along the Equator receive the maximum amount of solar radiation or sunlight. This explains why the Northern Hemisphere experiences snow and had four seasons unlike here in the Tropics which we have on two distinct seasons. The Seasons are formed due to the 23 1/2 degree tilt of the Earth on its axis TidesYesterday we spoke about the influence of the Moon on the tides (water level) of the Earth. There is a gravitational attraction between the Earth and Moon and to a lesser extent the Sun. The gravitational attraction between the Moon and Earth causes high and low tides. The Picture below gives a great representation of the formation of tides and judging from the oohs and aahs in class when you all say it! I'm sure that you all understood it ;)
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