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.
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.
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.
Web browser with Adobe Flash Player.
Evaluation and Observation
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
Potential Effectiveness as a Teaching Tool
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
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
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
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).