Peer Review

Gram Stain

Material Detail page

Reviewed:: Sep 2, 2018 by Biology

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Ratings

Overall Rating:

Content Quality:

Effectiveness:

Ease of Use:

Overview:: This module provides a description of gram staining including the purpose, the mechanism, the components, the methods and the interpretation of gram staining. This site also includes a step-by-step list of how to do a gram stain. Furthermore, there is a simulation that allows students to practice gram staining. During this simulation, one can view his or her example under the microscope as well as view actual slides of gram positive cocci in clusters, gram positive cocci in chains, gram positive diplococci, gram positive pleiomorphic rods, gram positive rods, gram negative rods, gram negative diplococci and gram negative pleiomorphic rods.
Type of Material:: Simulation
Recommended Uses:: Best suited to in-class activity with teacher present, could be done as homework, but this is less ideal because of lack of feedback from material that steps have been done correctly
Technical Requirements:: I viewed the website in Google Chrome Version 59.0.3071.115. Uses Java. Flash Required. Also tested in Safari and Opera in OSX
Identify Major Learning Goals:: To learn the purpose, mechanism, components, method, and correct interpretation of a Gram stain. To practice the steps of the Gram stain method To identify different kinds of bacteria based on Gram type and shape
Target Student Population:: high school and college microbiology, and allied health professionals
Prerequisite Knowledge or Skills:: Students will need basic computer navigational skills (enter URL, click and drag bar). Otherwise, the interface is very user-friendly. It assumes that students already have a good grasp of vocabulary like cocci, coccus, pleiomorphic, primary stain, and counter stain and so does not define them specifically within the material. It does not review the differences in cell wall structure between Gram-positive and Gram-negative cells and so students will need to recall this information on their own.

Content Quality

Rating:
Strengths:: Can be completed in as little as 5-10 minutes for diligent students Clearly and accurately demonstrates each of the major steps of the process
Concerns:: Simulation allows student to perform gram stain steps incorrectly or only do one step, but does not correct errors. Some visualization is incorrect: sample is not well mixed prior to loop being placed into sample, slide has liquid on it before loop with sample is placed on it, no indication that sterile H2O is used. When gram stain steps are completed, microscopic field shows blank field, but there are several examples that can be viewed. Can not adjust microscopic power when viewing. Simulation states viewing is at 1000X, but field of view is not as clear as it could be. Microscope images are fuzzy and not high quality.

Potential Effectiveness as a Teaching Tool

Rating:
Strengths:: Does give a basic overview of doing a gram stain. Does a good job of showing what a poor stain would look like when students do steps incorrectly. Summarizes each step in written format and in visual simulation.
Concerns:: Does not specifically identify prerequisite knowledge like necessary vocabulary. When students do not complete the steps correctly, they are not specifically informed of where they went wrong or even that they made a mistake at all. The Gram stain at the end will be inconclusive, but there is no prompt telling them “you messed up somewhere, try again!” So a student doing this without teacher guidance may not even know they messed up, especially if they aren’t comfortable with how different Gram stains should or should not look.

Ease of Use for Both Students and Faculty

Rating:
Strengths:: High quality visual design Easy to follow instructions
Concerns:: There is an enforced time requirement of one minute on certain steps, but no time requirement on decolorization, though instructions say it is 10-15 seconds. This inconsistency may confuse students who don’t know if they should wait or not.

Other Issues and Comments:: G rated. No sound or audio capability.
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