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MERLOT II


    

Peer Review


Connecting Concepts: Plant Biology/Water Relations 1: Water Potential Equation

by Jan Cheetham , Robert Jeanne
 

Ratings

Overall Rating:

4.87 stars
Content Quality: 4.9 stars
Effectiveness: 5 stars
Ease of Use: 4.8 stars
Reviewed: Sep 16, 2005 by Biology Editorial Board
Overview:

Plant Biology/Water Relations is one of a series of interactive web-based lessons designed to give introductory undergraduate biology students opportunities to connect biology concepts. Each lesson is a series of screens that breaks the topic down into simple steps and then illustrates the connections between the steps to present the completed concept or process. Students frequently have difficulty understanding why diffusion and osmosis occur and how water moves from the roots to the leaves in plants. This site explains the process in a step-by-step manner. It can be used as a supplement to the lecture to allow students to review the topic at their own pace and as many times as desired. This specific lesson topic covers the concept of water potential and how to solve the water potential equation. A very good help screen is provided to help students use the lessons. The larger site containing the entire series will be very useful at the introductory level

Learning Goals:

The major goal of this lesson is to help students understand how water moves from the soil to the tops of plants. More specifically, it explains the water potential and how to solve the water potential equation. This lesson topic contains specific learning objectives.

Target Student Population:

High school (AP level) through college.

Prerequisite Knowledge or Skills:

Students will need to have a basic understanding of the kinetic gas theory as it applies to diffusion and osmosis.

Type of Material:

Tutorial.

Recommended Uses:

This site could be used in many ways. 1. As the basis of a classroom lecture presentation. 2. As an out-of-class assignment before the topic is covered in class. 3. As a study tool for students after topic is presented in class.

Technical Requirements:

Use of a current web browser will be required. Macromedia Flash Player 6 plug-in is required.


Evaluation and Observation

Content Quality

Rating: 4.9 stars
Strengths:

  • A detailed step by step explanation of how water moves from the soil to a plant leaf.
  • Very clear animations illustrate both the math and cellular processes involved.
  • An excellent illustration of the power of osmosis and surface tension.
  • Site is highly interactive with numerous answers to be filled in by student—self grading.
  • The exercise is quantitative—students have to use the water potential equation to determine what will happen in a variety of circumstances.
  • Questions asked throughout lessons help student get feedback on understanding of concepts/process.
  • Animations clearly connect the different parts of each process into a coherent whole.
  • Application of concepts in the third section also illustrate reconstruction of damaged ecosystems.
Concerns:

  • Not a concept covered in this detail in most introductory biology courses. May be best suited for a botany course. Parts could be used in an intro course.
  • The first unit on the equations used to explain the movement of water is a bit dry - essentially an on-line lecture.

Potential Effectiveness as a Teaching Tool

Rating: 5 stars
Strengths:

  • A thorough explanation of a conceptually difficult concept for students.
  • Very interactive, with challenging questions at every step to ensure that students understand what is happening.
  • Could easily adapt this as an assignment, homework problem, or as practice for an exam.
  • Clearly demonstrates relationships between elements of each concept.
  • Quantitative aspects of the lessons are particularly good for students.
  • The site can be used in several ways—as a direct teaching tool in a distance learning course, as a lecture outline, as a review and study tool for students after topic covered in class.
  • Some of the questions asked will be challenging for introductory students.
  • Completion of plans for links to assessments and image/animation data bases will greatly enhance the usefulness of the site.
Concerns:

  • A bit technical at points in understanding and applying water potentials. Students can figure it out, but it will take them a while.

Ease of Use for Both Students and Faculty

Rating: 4.8 stars
Strengths:

  • All links work smoothly and quickly.
  • Animations are high quality.
  • Well organized and easy to navigate.
  • Instructions clear, especially when manipulating components and entering animations.
  • Instructors manual available; summarizes the contents of each of the lesson topics.
  • Glossary available for selected terms.
Concerns:

  • An overall site map may help if students want to go back to the first unit and review the equations.

Other Issues and Comments:

This series of lessons has outstanding potential for use by faculty and students everywhere. The concepts are broken down to simple parts and then reassembled by an interactive process and animations into a whole. This lesson clearly explains water potential and how to use the water potential equation.