Starry Night
What causes stars to appear to move across the sky during the night?
Earth rotates on its axis.
What is the name of Earth's movement as it spins around an imaginary line through its poles?
Rotation.
What object in the sky provides the light that creates your outdoor shadow during the day?
The Sun.
What is the name of Earth's movement around the Sun?
Revolution, or orbiting the Sun.
What is the name of the object that orbits Earth and appears in our night sky?
The Moon.
What are star trails?
Streaks recorded in long-exposure photographs as stars appear to move across the sky.
How long does Earth take to complete approximately one rotation?
About 24 hours.
What happens to a shadow when an object blocks light?
A darker area forms where the light is blocked.
What causes Earth's seasons?
Earth's tilted axis as Earth revolves around the Sun.
What is the name for the different shapes the Moon appears to have during the month?
Moon phases.
If you photographed the night sky for several hours, what pattern might the stars make?
Circular trails, because Earth's rotation makes the stars appear in circles.
What causes day and night on Earth?
Earth rotates, so different parts of Earth face toward or away from the Sun.
When are shadows generally shortest on a sunny day: around winter or summer?
Summer, when the Sun is highest in the sky.
During summer, is the Sun generally higher or lower in the sky at midday than it is during winter?
Higher in the sky.
Does the Moon make its own visible light, or does it reflect sunlight?
It reflects sunlight.
What is the name of the star that appears nearly stationary in the northern night sky?
The North Star.
When it is daytime where you live, what is happening on the side of Earth facing away from the Sun?
It is nighttime there.
Why does a shadow's length and direction change throughout the day?
The Sun's apparent position changes in the sky as Earth rotates.
Why do we generally have longer daylight hours in summer than in winter?
Our hemisphere is tilted toward the Sun during summer, so the Sun follows a longer path across our sky.
What causes the Moon's phases?
As the Moon orbits Earth, we see different portions of its sunlit half.
A student observes the same stars at the same time on several nights. Why might their positions appear similar, but not exactly identical?
Stars follow predictable patterns, but their apparent positions shift slightly from night to night as Earth rotates and moves in its orbit.
A student says the Sun moves around Earth once each day, causing day and night. What is wrong with this explanation?
Day and night are caused by Earth's rotation, not the Sun orbiting Earth each day.
A student places a stick upright in the ground and marks its shadow every hour. How could these marks help the student tell time?
The shadow's direction and length change in a predictable pattern, so the marks can serve as a simple shadow clock.
Why can we see different constellations in different seasons?
As Earth revolves around the Sun, the nighttime side of Earth faces different directions in space.
A student says the Moon's phases happen because Earth's shadow covers different parts of the Moon every month. Is the student correct? Explain.
No. Moon phases happen because of the changing positions of the Sun, Earth, and Moon. Earth's shadow causes a lunar eclipse, not the regular phases.