One of the central ideas behind microbiology is to see images that are not available to the naked eye. Through the use of digital microscopes, students in online courses can have exposure to those images, but the ability to view images of samples produced by the students is something that is not typically or easily replicated in an online course. The high cost of good-quality optical microscopes and the difficulty of using complex microscopes independently and communicating results are barriers to including this in an online lab course. Through the use of a lower-cost digital microscope that is easy to use, students are able to enjoy the experience of viewing images of microbes from their own sample and preparation.
Online learning has grown in popularity and is expected to increase in the coming years (Allen & Seaman, 2013), presenting a unique challenge for the biosciences. Many instructors consider the use of the microscope a cornerstone of bioscience learning. Students in face-to-face labs will spend considerable time working with the light microscope to view images; however, the cost of a typical classroom microscope puts it out of reach for students in most online classes.
Digital images and virtual microscopes have been suggested as a way to recreate the classroom experience for online learners. The use of digital images in replacing microscopy has become increasingly important and accessible to students (Schmidt, 2013). First established in the 1990s, this field has grown and offered an important tool for online students (Whalley et al., 2011). When using a digital microscope, students have the opportunity to view and manipulate microscopic samples they prepare. Here, we suggest the use of an inexpensive, digital microscope that students can purchase and use as part of an online lab course.
In order to test the ability and practicability of using inexpensive microscopes in the online learning environment, we purchased six Celestron MicroSpin 2MP digital microscopes, which can produce images ranging from 200× to 600× magnification. This microscope has a retail cost of $79.95, considerably less expensive than typical classroom microscopes (see Figure 1).
The students were asked to use the digital microscope as part of an established lab titled “Structure and Microscopy.” The purpose of the lab was for the students to learn Gram stain techniques. The regular lab assignment involved students preparing Petri dishes with bacterial growth. This was accomplished by sampling from various household sites. The Petri dishes were given up to a week to exhibit bacterial growth. Students then observed macroscopic growth on the Petri dishes and described the colony morphology. They also documented the bacterial growth by taking photographs.
The next step involved sampling the bacterial growth through standard aseptic technique. As the students were conducting the experiment in their homes, they used disposable tools rather than a Bunsen burner or bacteria sterilizer. They heat-fixed the samples to glass slides and then followed standard Gram staining techniques: (1) addition of the primary stain, Gram's iodine, followed by (2) addition of the decolorizer, and then (3) addition of the counterstain, safranin. Because the lab did not require access to a microscope, the students completed the procedure and then discarded the slides, observing only general color changes on them. The final assignment asked the students to complete a lab report in which they discussed Gram staining procedure and the general color change they observed macroscopically.
Students who received a MicroSpin microscope were asked to complete an additional assignment in which they used it to examine the slides and emailed the resultant images, along with descriptions, to the instructors. This assignment instructed the students on how to use the MicroSpin microscope, directing them to use it to produce photographs (micrographs) and to include these photographs in both the additional assignment and the final lab report. The descriptions they wrote described the cell morphology, cell arrangement, and observed color. Additionally, they determined whether the cells were Gram positive or Gram negative based on the color of the cells.
After completing the lab, the students were asked to fill out a survey discussing the ease of use of the microscope and their overall impressions of the assignments (a copy of the survey is available as Supplemental Material with the online version of this article). The completed assignments were evaluated by the instructors for quality and the ability of the students to produce images.
The major concern we had with involving students in this project was their ability to learn how to use the microscope. Manipulation of the microscope and focusing in on images is one of the tasks students struggle with the most, often requiring instructor assistance. Typically, in a face-to-face lab, the instructor is physically present to help students use the microscopes. However, the digital microscope is less complicated than a typical undergraduate microscope, so students spend less time learning the extra parts of the microscope and more time interacting directly with the technology.
Because the microscope in this study was a digital microscope, students were required to install compatible software, connect the microscope to a computer or laptop, and take photos or videos. As instructors, we tested the ease of use on multiple computer platforms (Windows and Mac; laptop and desktop) and found no compatibility issues. We also tested the use of the microscope to focus on multiple prepared slides and found the image quality to be reasonable. The students similarly reported in the survey that they had no issues, with 100% of the survey respondents selecting the choice “The microscope was very easy to use”; 75% of the students selected the choice “It enhanced my understanding of the staining procedure, but I still would have understood the major concepts without the use of a microscope”; and 25% selected “It greatly enhanced my understanding of the staining procedure.” None of the students selected the option “It did not enhance my understanding of the staining procedure.” All the students who had previous experience working with microscopes felt that using the digital microscope was comparable to their other undergraduate lab microscope experiences.
However, we acknowledge the possibility that future students might run into issues with the digital microscope. In that case, we would offer support to these students via online rooms and discussion boards that would allow the student(s) and the instructor to ask questions and troubleshoot. Any online room sessions would be recorded, and discussion boards would be available to the entire class to foster a collaborative feeling and to avoid overlap in explanations. Because students often have the same questions, having these questions and answers readily available will reduce the time the students have to wait for answers and decrease their frustration with technical issues.
Adjustments could be made to the assignment to accommodate large class sizes. Instead of individual assignments, the students would be asked to post their images and descriptions on a discussion board. This would give the students more exposure to images and more opportunity to discuss and interact with other students.
The quality of the images was sufficient for student learning, although not as clear as images that would be produced with standard lab microscopes. For future lab courses, we would recommend either supplementing with an additional lab focusing on eukaryotic cells or focusing solely on eukaryotic cells. The use of the microscope could also be expanded for use in field labs. This approach would give the students more time with the microscope and allow them to see more detailed images.
Summary of Recommendations for Using Digital Microscopes in Online Labs
Determine price range and locate a microscope with a minimum magnification of 400×.
Select a microscope whose software is compatible with multiple operating systems (Windows, Mac, Linux).
Use the microscope in multiple labs. Early labs should focus on pre-prepared slides and larger organisms. Eukaryotic cells and structures are most easily identified using these types of microscopes.
Have students share their images and participate in an online discussion board to enhance interaction.
The instructor should have access to and be familiar with the microscope and software to best assist students.
Use of a microscope is an important part of the biology lab experience. It is possible to recreate this experience in online labs through the use of an inexpensive digital microscope. However, limitations must be acknowledged and prepared for. These include focusing on larger, eukaryotic organisms and incorporating discussion boards to help students communicate technical issues and correctly identify cell structures.