A visual for student to see how hours of daylight is determined
by where the Sun shines most directly on Earth throughout the year
Concept: The change in hours of daylight throughout the year
is related to the change in seasons
- On the Summer Solstice, there is approximately 16 hours of daylight
- On the Vernal (Spring) and Autumn Equinox, there is equal hour of
day and night
- On the Winter Solstice, there is approximately 8 hours of daylight
Northern Hemisphere, Southern Hemisphere, Tropic of Cancer, Tropic of
Description: Using a flashlight as the Sun and the wall as
the Earth, the instructor demonstrates where the Sun shines on Earth most
directly during each season and how hours of daylight are determined
Room preparations -
1. Apply tape horizontally dividing the wall in half to represent
2. Label top half the "Northern Hemisphere" and the
bottom half "Southern Hemisphere." Label the distance ~ 1/4th
distance above the equator "Tropic of Cancer" in the Northern
Hemisphere and 1/4th the below the equator "Tropic of Capricorn."
1. Explain to students that because of the Earth's tilt, different
locations on Earth receive more or less direct sunlight as Earth revolves
around the Sun. (Display globe to show that Earth's axis is tilted 23.5
2. Use the flashlight to motion that during a year, direct sunlight
hits the Earth in a wave pattern as the seasons go by with the wave reaching
it's highest point at the Tropic of Cancer and it's lowest point at the
Tropic of Capricorn both 23.5 degrees respectively above and below the
equator. Have students to notice that the Sun shines directly on the equator
twice in a year.
3. Identify these times of year as the beginning of a new season
and have students infer the seasons from this discussion.
1. The first day of which two seasons have equal hours of daylight?
How was this determined?
2. The first day of which season is the longest day of sunlight?
3. The first day of which season is the shortest day of sunlight?
4. What season is it in the Northern Hemisphere if the Sun is
shining more directly above the equator?
5. What season is it in the Southern Hemisphere if the Sun is
shining more directly in the Northern Hemisphere?