EXPERIMENT: OBSERVING SHADOWS
You have learned that the earth revolves around the sun in an elliptical orbit. It takes about 365.242 days for the earth to make one trip around the sun. In this experiment, you will see how the angles of sunlight change as the earth orbits the sun.
These supplies are needed:
a large piece of brown wrapping paper or newspaper (about 4 feet by 8 feet); can be taped together
a black or dark brown crayon
masking tape
Procedure:
1. Place the paper on the floor so it is in the sunlight, as shown in the figure to the right. Tape the paper securely to the floor with the masking tape.
2. Once each week, for a total of four weeks, outline with the crayon the area in which the sunlight falls on the paper.
Make your drawings at the same time each week. For example, if your first drawing is made at 2 o'clock p.m., your other drawings should be made at 2 o'clock p.m. for each of the next three weeks.
3. As the earth revolves around the sun, the light coming in the window will shift. You will be able to see how the angle of the sun shifts as it strikes the paper. Label the date for each of your drawings.
Show your drawings to your teacher.
*You don't need to do it I just need the answers to these 2 questions
1.Explain the changing location of shadows made at the same time of day over four weeks' time.
2.Explain their meaning on the basis of what you have learned in this unit.
Answers
Answer:
The Sun appearing in the east
As the Earth’s axial rotation spins our planet towards the light of the Sun, we see the Sun appear in the east. Due to the Earth’s rotation, our view of the Sun changes throughout the day.
The spinning Earth
From our vantage point on Earth, it appears that the Sun moves across the sky during the day. We see the Sun appear to rise in the east and set in the west. Actually, the Earth is spinning (rotating on its axis) so it is our view of the Sun in the sky that changes during each 24-hour cycle of light and dark.
We see the sunrise when our location on Earth spins towards the light of the Sun. As the Earth continues to spin, we see the Sun higher in the sky. As the Earth spins away from the light, we see the sunset. The Earth continues to spin until we are in a shadow – our place on Earth is dark because the Sun’s light is blocked by the magnitude of our planet! We have several hours of night with our side of the Earth in darkness, and then as the Earth spins towards the Sun’s light, we see a sunrise. When New Zealand is in darkness during the night, the opposite side of the world is in sunlight.
Shadows change with the seasons
The tilt of the Earth’s axis affects the length of our shadows. During the summer, our location is tilted towards the Sun, so our midday shadows are very short. During the winter, our location is tilted away from the Sun, so our midday shadows are longer.