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MERLOT II


    

Peer Review


Oxygen Source For Photosynthesis

by
 

Ratings

Overall Rating:

4.75 stars
Content Quality: 5 stars
Effectiveness: 5 stars
Ease of Use: 4.75 stars
Reviewed: Feb 08, 2014 by Biology Editorial Board
Overview: This is a great, interactive animation to show that the source of oxygen from photosynthesis is water. The animation and accompanying narration shows the details of the experiments conducted by Samuel Ruben and Martin Kamen in 1941, where they used radioactively labeled oxygen to trace the outcome of oxygen during photosynthesis. As shown through this animation and with data displayed, the source of oxygen is shown to be from water. Users participate in the experiment and the animation / simulation does a nice job to guide them through the experiment. Conclusions are provided as well as a short quiz at the end of this learning exercise.
Learning Goals: No specific goals listed at the site. However, users will learn about the source of oxygen in photosynthesis.
Target Student Population: High school or lower division college students.
Prerequisite Knowledge or Skills: Understanding of basic chemical formulas and at least rudimentary previous knowledge of photosynthesis will help in understanding what is being presented.
Type of Material: Interactive animation with narration.
Recommended Uses: The material can be used in the classroom as a short animation during lecture and can also be used at home to learn about photosynthesis. Users can also use this material to perform a short experiment that demonstrates the source of oxygen during the light reactions.
Technical Requirements: Web browser with Adobe Flash Player.

Evaluation and Observation

Content Quality

Rating: 5 stars
Strengths:
  • The information is accurate and interesting
  • The site provides good historical background about photosynthesis
  • The experiment and its implementation are done very eloquently
  • The main goal of the learning object is clear and concise
  • The material provides a good balance of facts and experimentation
  • Material is clear and good quality
  • Historical information increases engagement with the topic
Concerns:
  • None

Potential Effectiveness as a Teaching Tool

Rating: 5 stars
Strengths:
  • The animation / simulation is active and engaging
  • The material is presented using the inquiry method, which stimulates critical thinking
  • This learning experience provides users with a good experience using scientific data
  • Users are well informed and use the information to do an experiment about the light reactions of photosynthesis
  • The site includes an intuitive learning goal
  • Conclusions and a quiz are provided with this learning object
Concerns:
  • The interactive bits could be more flexible--only one possible action is allowed, but two could be allowed

Ease of Use for Both Students and Faculty

Rating: 4.75 stars
Strengths:
  • The information is organized and follows a logical order
  • Animation flows very easily
  • Narrations and animations played simultaneously without problems
  • No defective links or major bugs were found
  • The buttons are all clear and work on both Mac and PC
Concerns:
  • No full screen option
  • Users can have either text Step-Through or continuous narration, but not both
  • The introduction and conclusion are text only, with no narration

Other Issues and Comments: This is an excellent description of a classic experiment shedding light on a fundamental issue in photosynthesis. The interactive section adds to the overall effectiveness of the resource. I recommend increasing the interactive part, so that students can select which component to label with O18 rather than having to do it in the order prescribed. I would also recommend a full screen option, narration for the intro and conclusion (to meet accessibility requirements).