Bringing experiential learning into the lecture theatre using 3D printed objects

Thank you for your comments and by addressing them I hope the manuscript has been improved. In the response below I have set out the changes made.

The work is more than using 3D printed objects, it is student-centred education, interactive and motivating and specially thought to address a problem in science, to enable visualization of abstract concepts, specifically in Biochemistry.
Thank you for your suggestions and I have altered the title to reflect your comments. "Active learning in the lecture theatre using 3D printed objects to visualise abstract concepts."

Many teachers also use 3D visualization programs, combining theoretical and computer laboratory sessions. Differences, advantages and disadvantages between these two approaches could be discussed.
The use of computer based representations is now easily accessible via personal devices. There are a wide range of 3D visualisation programs available which enable molecular structures to be moved, altered, rotated and interrogated. Programs such as the Java based Jmol applet allow students to manipulate molecules and investigate their structures. There are also a range of free programs that allow students to visualise molecules on smart phones and tablets such as "Molecules" for Apple iOS and "ESmol" for Android devices. These programs offer many advantages such as ready access to the > 118500 structures available in the protein data bank (PDB). However, their use as tool in large group teaching can be problematic as all students require access to a device. In addition providing technical support to 150 students across three different platforms within a lecture theatre can also be problematic. Molecular viewers do work very well in small group seminar or lab sessions where support can be given or devices can be provided. Students can be directed through a range of tasks and the molecules can be explored in greater depth (Harris, 2009). However, the tablet based applications lack the tactile aspect of physically handling the object in question and can prevent the abstract observations that generate the initial interactions. The models are also engaging and can be used by groups of people who have had little training, unlike the visualisation programs (Harris, 2009). The models also allow an ability to quickly make abstract observations for example the spiral nature of DNA or the large clefts on an enzyme. It is these abstract observations that  stimulate the initial peer-to-peer conversations. This approach allows the students to remain engaged with the topic and revisit their observations after the teaching session.  In a study in which 3D printed models were offered alongside a molecular imaging program the students tend to prefer the models when asked questions about molecular structure that required higher order thinking skills (Harris, 2008). The tactile nature of the models appears therefore to leads to a more lasting memory of the interaction (Hurman, 2006).
 
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What was actually done?
Molecules were handed around the group by the lecturer. They were handed out starting at the end of each of the rows of students. The students were asked to pass the molecules around and handle them directly. Once most of the students had handled the objects they were encouraged to talk with their peers about their observations.
Why were those structures chosen?
The two structures were chosen as they these molecules are established as examples within the taught material on the course. DNA is central to molecular biology and an understanding of how other molecules such as transcription factors interact with it is a key learning point in the Biochemistry program. Lysozyme was chosen as its structure and function are well understood. It also has a defined active site in which the substrate has been modelled. The use of lysozyme also integrated well with the rest of the module. Its action on the lipid polysaccharides found on the cell wall of gram negative bacteria resulting in lysis allowed links to microbiology and protein purification. It also integrates well with a second year structural biology practical in which lysozyme can be induced to undergo change from an alpha / beta structure to the beta sheet rich structure of amyloid fibrils resulting in a loss of function.
Which were the concepts students were expected to learn in each session?
The main concepts that the students were expected to learn was that the structure of a molecule brings about its function and subsequent properties.
What were the related learning outcomes?
In the DNA sessions the main learning outcome was to understand the difference between the major and minor grove within the structure of DNA and how proteins interact with these groves. Within the lysozyme sessions the learning outcome was to be able to identify where an active site maybe located on a protein and how a substrate would interact with it.
How many groups?
The session has been run twice a  year for three consecutive years with ~120 - 150 students being present at each session.
How many molecules?
Within each session 20 molecules were used.
Was the discussion tutored? If it was, how many tutors participated?
The sessions were run in a standard lecture theatre with one lecturer delivering the session.
The models seem very small, what were the structural features they had to identify mentioned in figure 3?
For the DNA molecule it was the major and minor grove. The models are scaled such that an index finger would fit into the major grove. In the case if the enzyme it was the active site located across the middle of the protein.
Costs?
£7 each for raw materials
 
As this experience was justified as a mean for conceptualizing 3D shapes for understanding Biochemistry, other reported experiences using molecules should be discussed and compared.
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The use of physical models as a learning tool have been used to depict molecular geometry in both biochemistry and chemistry (Dori, 2001). The benefit of these objects has been demonstrated in an analysis of visuospatial thinking in chemistry. In this study it was concluded that adept visual perception skills correlate with achievement. DNA and protein models assembled from coloured computer-printouts on transparency film sheets have also been demonstrated to aid students in grasping various aspects of biopolymers (Jittivadhna, 2010). Students who hold physical models in their hands gain a better understanding of molecular geometry, than they could achieve solely from viewing images on a printed page. It has been reported by both Herman (2006) and Bain (2006) that physical models that can be easily manipulated, can play an important role in capturing the interest of students and encouraging deeper sophisticated thinking (Bain, 2006). Additionally, the students gain a language for talking about the concepts in question and enhance their understanding of abstract concepts by handling models (Wu, 2004).
The positive comments from students polled in this study, in which 3D printed models were rated as most useful, are echoed in a comparable study where a side-by-side comparisons of seven different learning tools were undertaken by students in an introductory biochemistry class (Roberts, 2005). In that study, the models were shown to have an important role in capturing the interest of the students and stimulated sophisticated questioning. The main difference between these observations and those presented here, relate to the learning environment. Within the side-by-side comparisons study, the core concepts were introduced in a lecture and the models were handled as part of a 3-wk laboratory in a group of twenty students, generating tangible learning gains were observed. In the study discussed here, however, 150 students were allowed to handle the models directly within the lecture environment. Handling the models aided the students in visualising the molecules demonstrating the applicability of this approach to large group teaching. Schönborn, (2006) states that the ability to visualise ideas is a key skill for all students and it is a key skill for biochemists who are often presented with a range of visual interpretation including drawings, images, dynamic visuals, animated visuals, multimedia, and virtual reality environments. The use of models has the potential to help students construct their own visualisation and understanding of these molecules as demonstrated by the student comments reported here.
The main weakness of this work is that no assessment of the approach is included.
On the advice of both reviewers the perception of the students was assessed via a written questionnaire. Students in their final year of study were asked to reflect on the use of the models during their past learning. 44 students were questioned and 35 remembered using the models. 32 of these responded with positive comments and 3 with neutral comments. Of the 9 students who did not remember using the models many admitted to not having attended the lecture.
 
The following text and supplementary information has now been added. In addition comments have been referred to in the discussion section.
 
Results
Students in their final year of study were asked to reflect on the use of the 3D printed models during their past learning. 44 students were asked "Did you find the models helpful, if so how?" through an anonymous survey. Of the 44 responses 35 remembered using the models and 32 of these responded with positive comments (3 with neutral comments). Of the 9 students who did not remember using the models many admitted to not having attended the lecture.
Some students commented on the benefits the models provided as a visual aid,
"they were very useful for highlighting the key lecture points as well as being a visual aid."
Student comments also highlighted the use of the models as a tool in understanding the key learning objectives,
"Very useful to help understand major and minor grooves", and
 "Allowed us to visualise the major and minor groove of DNA, as well as the binding sites for enzyme".
 The students also explained that the models provided an alternative way of presenting information,
"they gave a 3D better understanding of the 3D structure of the enzyme than a 2D computer image."
It was also noted that the models could be used to gain a sense of scale, for example,s the difference in size between a ribosome and organelles. The full list of comments is included as supplementary information. During each of the sessions there was a high level of student engagement involving the students talking to each other and to the lecturer with the key learning points being recalled three years after the teaching session.
Did the students seem motivated?
Yes there was a high level of engagement during the sessions; the students were talking to each other and to the lecturer.
Did they participate more actively than in other activities?
The participation level was probably equivalent to other sessions. However I have noted that a range of activities within the sessions a good way to keep students motivated and engaged. Too much of any intervention can lead to disengagement as has been reported for flipped classroom approaches.
Did they comment informally positive aspects?
See above response
Another approach could be to analyze exams answers regarding the concepts that were studied in these special sessions and compared them to those of the previous year.
Unfortunately we do not hold the exam scripts locally and so gaining access to this is not possible. However it will be built into further studies as it is a good suggestion.