The Earth takes 24 hours to make one complete turn. Why do we have day and night? We have day and night because the Earth rotates. It spins on its axis, which is an imaginary line passing through the North and South Poles. The Earth spins slowly all the time, but we don\’t feel any movement because it turns smoothly and at the same speed. How long does it take the Earth to turn around? The Earth takes a whole day (24 hours) to makea complete turn. Why is the Sun in the sky at some times and not at other times? At any time half of the Earth faces the sun. This part has day. The other half of the Earth faces away from the Sun. It receives no light. It is dark and has night. The sun is the source of light for day. Why does the sun seem to move across the sky?
The Sun does not move. It seems to move across the sky starting in the east in the morning, moving toward the south at noon, and then toward the west as the day ends. It is the Earth turning that makes it seem as though the Sun is moving.
The styrofoam ball represents the Earth. Draw the outlines of the continents on the styrofoam using a pencil. You will use the globe model (shown by your teacher) or the map of the globe on the projector as drawing guides. The drawing does not need to be detailed. Just make sure to draw the Philippines clearly. Include also Brazil which is on the opposite side of the Philippines. Color the drawn continents (land) green and the ocean (water) blue using the highlighters.
Students must cooperate in drawing and coloring their own БEarth. Б Carefully pierce the barbecue stick through the middle of the styrofoam ball. Use the marks as guide. The barbecue stick represents the line about which the Earth spins or rotates. This represents the Earth\’s axis of rotation. Take the two pieces of straws. Insert them over each end of the axis piercing the styrofoam ball. Make sure that they cover the barbecue stick entirely. Take the illustration board and investigate. The number written on it (degrees, symbolized as O) is a measure of the tilt of the Earth. Remember that the EarthБs axial tilt is 23. 5O degrees. Stick the two ends of the straw along this axis using the tape. Fold the flap to make the stand.
The Earth should turn freely when you try to rotate it. You are almost done. Put the Philippine flag in place and also the Brazil flag opposite it. The flags represent the two БextremeБ positions on Earth. Make the room completely dark. Using the flash light (representing the БSunБ), shine sunlight onto the Earth. The flashlight should not move. When light strikes the Philippine flag (day), take note that no light falls on Brazil (night). The Philippines is at Бnoon,Б the light shines directly on it. Then turn the globe eastward (from left to right) slowly until their positions reverse. Brazil now experiences daylight while Philippines experiences nighttime. As the БEarthБ moves, this pattern continues.