of Earth Science |Northeastern
Daily Objectives #2 (August 30,
the end of today's class, you
should be able to do the following:
v From last time: Describe
the purpose and function of a rain barrel, and make quantitative
calculations to estimate how a rain barrel is involved in the water
budget of a residential property in Chicago.
v Continued from last time: Work in a team to
complete today's assignment, due by the beginning of next class:
collect all the information you need and make all the calculations
required to answer questions on the slides with white
backgrounds. You must complete this assignment by
Thursday's class, but will not hand it in. The
PowerPoint presentation from last class appears here.
v New this time: Use concepts of
length, area, volume, and flow rate to quantify hydrologic variables.
v Solve a hydrologic
problem in a sequence of logical steps, using reasonable units and
Our agenda today:
Teams get together to go over their calculations
Compare answers between teams:
How big is the property? How does the
area compare to an acre?
How much of the property is in garden plots?
What is the area of the roof?
What is a typical rainfall in Chicago?
How much rain will the roof collect in a
Would it fill the two barrels?
How many barrels would fill in a typical
What depth annual precipitation do we get in
What volume annual precipitation do we get in
What accounts for the differences between
answers? Discuss issues of precision, accuracy, error, and
is an abbreviated list; see more at "Hints for Solving
Teams choose one problem (from list below) to work on using the
problem-solving format given:
List what you know about the situation ("Given").
Write what the problem asks you to find, or what the goal is ("Find").
Draw a sketch of the situation.
Break the problem into smaller steps.
Choose one part or step of the problem and write a brief heading to
explain what that step is about.
Solve that part, writing units of measurement at every step. Use "dimensional analysis"
as described in your textbook!
Put a box around the answer.
Then move on to the other steps, writing a brief heading for each one.
When you solve the final problem, put a box around the answer.
1) How big
is the property? How does the area
compared to an acre? How big is an acre (in non-technical terms)?
2) How much
of the property is in garden plots? How much water would be
needed to give the gardens one inch of water?
3) What is
the area of the roof? How much rain will
the roof collect in a typical rainfall?
depth annual precipitation do we typically get in Chicago?
annual precipitation do we typically get in Chicago?
5) What is
a "typical rainfall" in Chicago? Would it fill
the two rain barrels?
that finish early should consider these questions:
Homework: For Tuesday,
as a group (one set of answers for the whole group), complete Homework
- How many
rain barrels would fill in a typical rainfall in
- If the
rain falls at a
rate of 1 inch per hour, how long would it take to fill a
would a full rain barrel be?
© 2007 Laura L.
Last updated August 30, 2007.