Natural Sciences and Technology Grade 6 Term 4: Planet Earth and Beyond Movements of the Earth and Planets (ppt 1)

Topic 2 Movements of the Earth and Planets Rotation and Revolution [part 1] Natural Sciences and Technology - Grade 6

Natural Sciences and Technology - Grade 6 Rotation rotation = movement of an object around its own axis. Image: www.windows2universe.org Natural Sciences and Technology - Grade 6

Natural Sciences and Technology - Grade 6 Revolution Revolution = movement of an object in space around another object. Image: www.windows2universe.org Natural Sciences and Technology - Grade 6

Natural Sciences and Technology - Grade 6 Earth’s Rotation Turning of Earth on its own axis. The Earth’s axis is tilted. Causes day and night. Takes the Earth 24 hours to rotate. The rotation is like a wheel on a bicycle. It takes 24 hours for Earth to move around once (make a full circle). You could ask a learner to stand in front and in the same position slowly turn around starting and ending in the same position and explain it takes Earth 25 hours to do the same thing. Natural Sciences and Technology - Grade 6

Natural Sciences and Technology - Grade 6 Day and Night The Sun gives off light and heat. The Sun sets in the west and rises in the east. Do the activity where they colour in where it is day or where there is night. Explain that the side of Earth facing the sun is lit up and the side of Earth away from the Sun is dark (shadow) so it is night time. The next slides shows this. In other words only one side of the Earth gets light at a time. Natural Sciences and Technology - Grade 6

Natural Sciences and Technology - Grade 6 Earth’s Revolution Earth orbits the Sun. Earth takes 365 ¼ days to go around the Sun. The revolution of the Earth around the Sun causes the seasons (summer, winter, autumn and spring). As the Earth completes one orbit of the Sun, different parts tilt towards and away from the Sun. Orbit is oval shape. Remind the learners that all the planets move around the Sun. Remind them from the first work they did that the planets all have different times to make one lap around the Sun. It takes one year (365 ¼ days). The year is divided into 12 months and the twelve months are divided into four seasons = summer, autumn, winter, spring. The next slide shows a position on the globe and how with the Earth revolving the seasons change. Natural Sciences and Technology - Grade 6

Natural Sciences and Technology - Grade 6 Seasons Seasons occur because Earth receives different amounts of heat and light, because the track is oval NOT round so the orbit path is elliptical. At times Earth is closer to the Sun and others further away. So it is cooler when further away and warmer when closer to the Sun. Seasons occur because the pathway is elliptical and because Earth is tilted, the side that faces the Sun has summer and the side away from the Sun has winter. Seasons change around the 21st of June, September, December & March. Using the Globe and light source now not only turn Earth on its axis but move it around the light source (here a lamp with no shade will work better). Natural Sciences and Technology - Grade 6

Movement of Earth, Moon and Sun The Figure shows how the Earth orbits the Sun, the Earth rotates, the Moon orbits the Earth. Now would be the best time to either do some revision questions or the activities as set out in the guide. Natural Sciences and Technology - Grade 6