TEKS 8.7A: Model and illustrate how the tilted Earth rotates on its axis,
causing day and night, and revolves around the Sun causing changes in
seasons.
What causes day and night?
• An imaginary line that
passes through Earth’s
poles is called its axis.
Earth’s axis is tilted about
23.5 degrees.
• Earth spins, or rotates,
around its axis once every
24 hours, causing day and
night.
1. Explain What causes day and night?
TEKS 8.7A: Model and illustrate how the tilted Earth rotates on its axis,
causing day and night, and revolves around the Sun causing changes in
seasons.
What causes Earth’s seasons?
• Earth revolves around the sun once every year.
• Earth is tilted at an angle of 23.5 degrees on its axis.
• Seasons are caused by the combination of these two
factors.
2. Identify Identify the two reasons for seasons on Earth.
TEKS 8.7A: Model and illustrate how the tilted Earth rotates on its axis,
causing day and night, and revolves around the Sun causing changes in
seasons.
How does sunlight strike Earth?
• Near the equator,
sunlight hits Earth’s
surface from almost
overhead.
• Near the poles, sunlight
hits Earth at a steep
angle.
• This makes areas near
the equator warmer than
areas near the poles.
3. Explain Why is it warmer near the equator than near the poles?
TEKS 8.7A: Model and illustrate how the tilted Earth rotates on its axis,
causing day and night, and revolves around the Sun causing changes in
seasons.
How does each season occur?
• When the Northern
Hemisphere faces
toward the sun, it is
summer there and
winter in the Southern
Hemisphere.
• When the Northern
Hemisphere faces away
from the sun, it is winter
there and summer in
the Southern
Hemisphere.
4. Explain Explain how Earth’s axis is oriented
in relation to the sun for each season in the
Northern Hemisphere.