Conduct
this session in the schoolyard.
- Provide each student with a copy of the Puddle Lab Sheet. Choose
one of several options when organizing the class for the experiment.
One option is to use a single puddle and let different students gather
data at different times of the day. Another option is to use several
puddles and assign a group of students to each puddle. The experiment
may be performed on puddles created by rainfall or by water from a
hose. For each puddle, the class will need a watch, a Celsius thermometer,
and a meter stick.
- Read aloud the question on the lab sheet and instruct students to
write their hypotheses. Review methods of taking temperature, measuring
in centimeters, and telling time. Relate the importance of measuring
the width of the puddle in the same direction each time.
- Collect
data several times during the day, as your schedule allows.
- After
collecting data, provide time for students to draw graphs and write
conclusions. (See Preparing
Graphs and Charts in
the Project Action Guide.) Instruct students to draw
a bar
graph or line graph showing the time elapsed on the x-axis and
the width
of the puddle on the y-axis.
Option for advanced students:
Direct
students to draw their graphs to illustrate the change in area,
rather than
width, over time. Students will use the width of the puddle as
an approximate diameter (as long as the puddle is approximately
a circle).
They will
divide the diameter by 2 to find the radius and use it in the formula
for the area of a circle.
- When students have finished, discuss
how the graphs illustrate evaporation of water and how the experiment
relates
to wetlands that are wet during only part of the year.
Next: Classroom Assessment Suggestions
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