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Gold Seal Lesson:
Preparing
Solutions
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Copernicus
Education Gateway
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Subject:
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Science
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Grade:
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9-12
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ICLE Standards:
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Mathematics:
Use and value the connections between mathematics and other
disciplines.
Science: Develop the abilities of scientific
inquiry.
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Performance Task:
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Laura's father operates a greenhouse. Laura
understands that her father must germinate strong healthy plants to sell to
retail stores, florists, and landscaping businesses. Laura has noticed that
to produce quality plants, they must receive the proper amounts of water,
sunlight, warmth, and plant nutrients. She understands that not every plant
needs exactly the same growing conditions. The concentration or amount of
one factor that is just right for one kind of plant may be too much or too
little for another. Therefore, it is very important for Laura's father to
keep accurate data on each kind of plant he grows in the greenhouse. Laura
is learning how to prepare different concentrations of solutions in her
chemistry class. Obtaining this knowledge has helped her gain a greater
appreciation of the skills and knowledge necessary to run a greenhouse and
become a valuable assistant to her father.
Materials needed:
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plant starting pots
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fertilizer
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metric ruler
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graduated cylinder
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vermiculite
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marigold seed
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Working in groups of 4-5 students, prepare 100 grams of 0, 1, 5, 10, and
15 percent fertilizer solutions. Use the following formula to determine the
number of grams of water that must be added to the fertilizer to produce
the proper percent solution.
For example, to prepare 25 parts per hundred (pph) or 25% solution of
fertilizer use the following ratio.
Solving for x, x = 75 grams of
water.
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Fill 25 starting pots with a sterile growing medium (vermiculite). Plant
one marigold seed in each of the twenty-five pots. Label five pots 0%, five
pots 1%, five pots 5%, five pots 20% and five pots 15%.
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Each week after the seeds germinate apply 10 ml of each solution to the
appropriately marked pots.
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Ask the plants grow, measure the height in cm, the stem diameter in mm,
the distance across each plant from leaf-point in mm. Also note the color of
the leaves compared to the control plants (0%).
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Each student is to construct a data collection table for each group of
pots with the headings "Height, Stem diameter, Width, and Color (pale,
dark, black)." Find the average of the variables for each set of
plants and record in your data collection table.
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Each student is to construct a graph for each set of data, placing the
number of days on the x-axis and the measurable variable on the y-axis.
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Each student is to analyze his/her graph to determine which (if any) of
the solutions produced the best plant. Write a paper discussing and
defending your conclusions.
Note to the teacher: The purpose of this learning activity is to gain the
knowledge and skills necessary to prepare various concentrations of
solutions expressed by percent mass, in parts per hundred (pph), parts per
thousand (ppt), and parts per million (ppm). The student will also be able
to determine the best concentration of prepared liquid fertilizer in a
controlled experiment.
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Knowledge / Skills:
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Perform operations with signed (positive and
negative) numbers, including decimals, ratios, percents, and
fractions. (m1)
Understand the best procedures for statistical
data collection, organization, and display. (m5)
Understand the use of variables in expressions
such as 4x, x+2, and 2x-1, solve for the variable, and know how to
represent expressions such as "twice the number" or "four
more than the number" using variables. (m7)
Understand the characteristics of measures of
central tendency (i.e., mean, median, and mode). (m15)
Know and apply the principles of scientific
inquiry. (xs1)
Follow written directions carefully and
accurately. (ela6)
Use writing as a tool for learning in formats
such as learning logs, laboratory reports, note-taking, and journals. (ela40)
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Rubric:
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3 Points -
The student makes a complete response to the learning activity.
He/she demonstrates a complete understanding of the mathematical and
scientific concepts of concentration of solutions. The student uses the
appropriate mathematical operations to complete the task and is able to
draw conclusions through the analysis of his/her data. The paper discussing
and defending conclusions is thorough and convincing.
2 Points = The student makes a complete response to
all parts of the learning activity, but can only realize success with
coaching. He/she has difficulty making conclusions based on the data
collected. The paper discussing and defending conclusions is vague and
weak.
1 Point = The student demonstrates little understanding of how to
prepare solutions to a specified concentration and does not appear to
understand the use of controls and variables in a scientific experiment.
He/she is only able to perform the simplest mathematical procedures. The
student does not make any conclusions. His/her written paper, if completed,
is meaningless.
0 Points = The student does not
complete the task or make any conclusions. No written paper is attempted.
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Keywords:
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CHEMISTRY
LAB EXPERIMENTS
SOLUTIONS
LIFE SCIENCE
PLANTS
EARTH SCIENCE
SCIENTIFIC INQUIRY
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Grades:
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Kg [] - 1 [] - 2 [] - 3 [] - 4 [] - 5 [] - 6 [] - 7 [] - 8 [] - 9 [X]
- 10 [X] - 11 [X] - 12 [X]
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ICLE Application:
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D
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© 2000 International
Center for Leadership in Education
1587 Route 146 - Rexford - NY - 12148
518.399.2776 Fax: 518.399.7607
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