The Earth

What the syllabus asks of you

• Know that the Earth is a planet that rotates on its axis, which is tilted, once in approximately 24 hours, and use this to explain observations of the apparent daily motion of the Sun and the periodic cycle of day and night
• Know that the Earth orbits the Sun once in 4 Define average orbital speed from the equation approximately 365 days and use this to explain the periodic nature of the seasons v = 2π r / T where r is the average radius of the orbit and T
• Know that it takes approximately one month is the orbital period; recall and use this equation for the Moon to orbit the Earth and use this to explain the periodic nature of the Moon’s cycle of phases