Day and Night
What causes day and night on Earth?
Earth rotating on its axis.
What are the two major factors that cause Earth’s seasons?
Earth’s axial tilt and revolution around the Sun.
What is the name of the imaginary line dividing Earth into the Northern and Southern Hemispheres?
Equator
What is the imaginary line that Earth spins around?
Earth's Axis
During summer, would your shadow at midday generally be longer or shorter than during winter?
Shorter
A location on Earth is facing the Sun. Is it experiencing day or night?
Day
When a hemisphere is tilted toward the Sun, does it receive more direct or indirect sunlight?
More direct sunlight
Which generally experiences less variation in daylight throughout the year: locations near the equator or locations farther from it?
Locations near the equator
What is the term for Earth spinning on its axis?
Rotation
During which season is the Sun generally positioned higher in the sky: summer or winter?
Summer
If the United States is facing the Sun, what would generally be happening on the opposite side of Earth?
Night
If it is summer in the Northern Hemisphere, what season is occurring in the Southern Hemisphere?
Winter
During which season would St. Louis generally experience its longest daylight hours?
Summer
What direction does Earth rotate?
Counter-Clockwise
Scientists shine identical lamps onto two surfaces.
Which surface should experience the greater temperature increase?
Surface A, because the light is more concentrated.
The Sun appears to travel across our sky from east to west. Is the Sun actually moving around Earth every day? Explain.
No. Earth’s counterclockwise rotation makes the Sun appear to move from east to west.
Why does direct sunlight generally produce warmer temperatures than indirect sunlight?
Direct sunlight is more concentrated over a smaller area, while indirect sunlight is dispersed over a larger area.
While the Northern Hemisphere is experiencing its longest days, what is happening to daylight hours in the Southern Hemisphere?
The Southern Hemisphere is experiencing its shorter days because the hemispheres experience these patterns during opposite parts of the year.
What is the term for Earth traveling around the Sun?
Revolution
Imagine Earth is shown at a point in its orbit where:
Northern Hemisphere → tilted toward Sun
Southern Hemisphere → tilted away from Sun
Predict:
A. Northern Hemisphere season
B. Southern Hemisphere season
C. Which hemisphere receives more direct sunlight?
A. Summer
B. Winter
C. Northern Hemisphere
A student says: “Day and night happen because Earth revolves around the Sun.”
What is wrong with the student's explanation?
Earth’s rotation, not its revolution, causes day and night. Earth spins on its axis, causing locations to rotate toward and away from the Sun.
A student says:“Summer happens because Earth gets much closer to the Sun.”
Use evidence from the Earth-Sun system to correct them.
Seasons are caused primarily by Earth’s tilt and revolution, which change the angle/intensity of sunlight received by each hemisphere—not simply Earth being closer to the Sun.
Describe the daylight hours for the North Pole in June.
24 hrs of Night
If Earth suddenly rotated clockwise instead of counterclockwise, where would the Sun appear to rise and set?
The sun would rise in the west and set in the east.
Earth's axial tilt is necessary for the seasonal patterns we experience.
Give one piece of evidence and reasoning supporting this claim.
When a hemisphere is tilted toward the Sun, sunlight hits it more directly and is more concentrated, producing warmer temperatures. When that hemisphere is tilted away, sunlight arrives at a lower angle and is less concentrated, producing cooler temperatures. As Earth revolves around the Sun, which hemisphere is tilted toward the Sun changes.