5.8C
Day Night- Earth Apparent Motion
Earth's Rotation
Earth rotates once every 24 hours in a period known as a Day/Night Cycle. During this time, the part of the Earth that is facing the Sun is experiencing day and the part that is facing away from the Sun is experiencing night.
As the Earth continues to rotate, the areas change from day to night and back again. One full turn, takes approximately 24 hours. In general, areas on Earth will experience one period of daylight and one period of nighttime during this 24 hours.
Click Link Below to watch study jams on Rotation
Think Central Virtual Lab- Rotation
Sun's Apparent Movement across Sky
Shadow
On a warm summer day, you can cool off by sitting in the shade. You might find shade beneath a tree, under an umbrella, or next to a building. When you sit in a shaded area, you are actually sitting in a shadow. Shadows form because light does not shine through most objects. A shadow is the unlit area behind an object.
The Sun's apparent motion from east to west across the sky causes objects on Earth to cast shadows. The size of a shadow depends on the angle of the light that is hitting it. When the sun is low in the sky in the morning, shadows are long.
You are only a few feet tall, but your shadow is several feet long at sunrise! As the day progresses and the sun’s position changes, your shadow gets shorter. By midday, the sun is directly overhead. Your shadow is small and just under your body. At noon, your shadow is at its smallest. In the afternoon, your shadow starts to grow longer again. However, it is pointing in the opposite direction as your morning shadow. At sunset, your shadow is long once again. This pattern repeats every day.
The changing position of the shadow cast by an object during the day indicates a change in time. The sundial is one of the oldest, if not the oldest, known device for the measurement of time. A sundial uses shadows on a scaled surface to tell time. Sundials are not always accurate, but they do make the pattern of changes in shadows easy to see.
Shadow Game- Play with the shadow
Use the above link to access a Think Central white board lesson on Earth's rotation. (use only slides 1-4