Sunrise, Sunset, and Seasons
1-2 periods, then ongoing is optional (see step 2)
* Try to start this activity in the fall.
chart paper, daily newspaper (optional)
Students track photoperiod (daylight hours) over time and predict how
daylight will change during different seasons. This helps build their
understanding that ever-changing daylight is the driving force for migrations
and all other seasonal changes.
Ask, Which season do you think has the most daylight hours? The
least? If students are stumped, ask, How do you spend your
time after dinner in the summer? In the winter? Why do you think the
amount of sunlight changes over the year? What questions do you have?
students’ ideas on a chart that they can revisit and revise at
the class to discover how the amount of daylight changes throughout
the school year.
students to hypothesize about whether the amount of daylight
(called photoperiod) will increase or decrease between fall
and winter, winter and spring, and spring and summer. Have
them explain the thinking behind their responses.
up a class chart, or have students use individual charts,
to write down the sunrise and sunset times for your location
each day, each week, or only on the equinoxes and winter solstice.
To locate these times, students can check the local paper
or use the form on this Web site: Complete
Sun and Moon Data for One Day. (Because you can punch
in any date on the form, you can jump ahead to future dates,
such as the first day of each season. This will enable you
to complete the activity in just one or two class periods.)
Older students should make charts for 2 additional locations
– one north of you and one south of you. (To make this
more engaging, try to set up an exchange with other classrooms.)
your students are participating in Mystery
Class, they will receive this information for 10 classrooms
hidden around the globe!
Also have students track the maximum or average temperatures
for each location. (They can locate this through the National
students have gathered the data, they should calculate the
photoperiod (hours of daylight) – and high or average
temperatures, if they have them – for each date; see
Calculating Photoperiods. Finally, they can graph their
data (see Graphing
The number and rate of changes in daylight hours
varies according to the latitude of a location. The greatest
and most rapid changes occur farthest from the equator
(at the poles). On the equator, the daylight hours are
close to equal all the time.
north of you in this hemisphere should have more hours
of daylight during the summer (between the Vernal and
Autumnal Equinox) and fewer hours during the winter (between
the Autumnal and Vernal Equinox). Those locations south
of you in this hemisphere have the opposite pattern. The
tilt of the Earth’s axis as it rotates and orbits
around the sun causes these changes in daylight hours
through the seasons.
students revisit and revise their responses charted during
Laying the Groundwork.
and Journaling Questions: