Gold Seal Lesson:
Transpiration

Copernicus Education Gateway

 

Subject:

Science

Grade:

 

 

9-12

 

 

ICLE Standards:

 

 

Mathematics: Use and value the connections between mathematics and other disciplines. Extend understanding of the process of measurement. Understand and apply rates and percentage.

Science: Develop an understanding of how plants obtain and give off water.

 

 

Performance Task:

 

 

Willie's grandmother gave him a terrarium for his birthday. He noticed that when he watered the plants and put the glass cover back on, water formed on the glass. He wondered what caused this and how much water actually formed on the glass.

This activity requires you to estimate the amount of water that is transpired by a plant and to calculate the percentage of water that was actually used by the plant, the amount that was transpired, and the transpiration rate. You will also compare the percentage of water used by different sized plants and make conclusion.

Materials Needed:
Potted tomato plants
String
Graduated cylinder
Water
Plastic bags

  1. Select one of the potted tomato plants. Allow the soil to dry to the point where the plant begins to wilt.

  2. Add water to the pot until it begins to seep from the bottom of the pot. Devise a method to measure the water that you added to the plant and a method to measure that which seeped out so that you know the exact amount of water that the plant took in. Keep track of these amounts.

  3. Surround the plant with a clear plastic bag and securely tie it at the base of the stem. Place the plant under a light for 24 hours.

  4. Turn the covered plant upside down so that the condensation in the bag can collect in the bottom. Cut a corner of the bag and drain the water into a graduated cylinder. Record the amount of water in the cylinder.

  5. Find the percent of water that was transpired by the plant. Compare your percentage with that of other students in the class. Note the various sizes of plants used by different students. Does there seem to be a relationship between the percentage of transpiration and the size of the plant? If so, what is that relationship? Can you make any conclusion?

  6. Calculate the rate of transpiration per hour for your plant?

  7. Suppose you are a tomato farmer. You set 5000 plants about the same size you used in this activity. A severe drought sets in the day you plant the tomato plants. How much water will be needed each day to keep the plants from wilting. Justify your answer with calculations and/or written statements.

Note to the teacher: This activity can be used to show students the integration of basic arithmetic operations with the scientific principle of transpiration. Upon completion of the activity, students should have a better understanding of percentage, rates, and measurement, and how these mathematical tools can be applied in science and in the real world. Students should also have an understanding of the principle of transpiration of water in plants.

 

 

Knowledge / Skills:

 

 

Perform operations with signed (positive and negative) numbers, including decimals, ratios, percents, and fractions.  (m1)

Use the technique of dimensional analysis to convert units of measure (e.g., convert km/hr to m/min).  (m33)

Know and apply the principles of scientific inquiry.  (xs1)

Know the structure and functions of roots, stems, and leaves.  (s11)

Understand physical/chemical change (e.g., change of phase between gases, liquids, and solids).  (s57)

Observe and interpret energy and change relationships with the understanding that change occurs simultaneously at the interface between two parts of the environment where there is an energy exchange.  (s60)

 

 

Rubric:

 

 

3 Points  =  The student completes all parts of the task independently. He/she performs the necessary mathematics calculations accurately. The student demonstrates measurement skills and an understanding of percentage. He/she is able to make and justify conclusions concerning the transpiration of water in plants and can apply his/her knowledge of transpiration in a real-world problem situation.

 

 

2 Points  =  The student needs some help to complete all parts of the task. He/she has a fairly good understanding of the mathematics involved in the task, but makes some minor errors in calculation. The student has some inaccuracies in his/her measures. The student has difficulty making and justifying conclusions concerning the transpiration of water in plants, but his/her attempt shows some understanding of the concept. The student needs help in applying transpiration concepts in a real-world problem situation.

 

 

1 Point  = The student needs constant assistance in carrying out the task. He/she demonstrates a lack of understanding of the mathematics needed in the task and of the process of transpiration. He/she is unable to state any conclusions concerning the transpiration of water in plants and is unable to apply any knowledge of it in a real-world problem situation.

 

 

0 Points  =  The student does not complete the task and shows little, if any, understanding of transpiration. He/she lacks the necessary mathematical skills and understandings to apply the mathematics in the task. Little effort is applied and the student shows no ability to apply the concepts in a real-world problem situation.

 

 

Keywords:

 

 

LIFE SCIENCE
PLANTS
SCIENTIFIC INQUIRY
LAB EXPERIMENT

 

 

Grades:

 

 

Kg [] - 1 [] - 2 [] - 3 [] - 4 [] - 5 [] - 6 [] - 7 [] - 8 [] - 9 [X] - 10 [X] - 11 [X] - 12 [X]

 

 

ICLE Application:

 

 

D

 

 

 

 

 

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