Lesson

Adapting a Traditional Laboratory Exercise to Become Inquiry Based: An Example With an Introductory Biology Lab in Diffusion

Author(s): Karin E. Kram*1, Maryam Eslami2

1. California State University, Dominguez Hills 2. University of California, Irvine

Editor: Scott Gehler

Published online:

Courses: Introductory BiologyIntroductory Biology Science Process SkillsScience Process Skills

Keywords: protocol Diffusion Variables hypothesis science process control scientific efficacy

455 total view(s), 37 download(s)

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Abstract

Resource Image

Authentic research experiences are effective in fostering self-efficacy and increasing retention in STEM, particularly among minoritized student populations. Many instructors have sought to bring these to a wide range of students in the form of course-based undergraduate research experiences (CUREs). However, implementing CUREs can be challenging, especially at under-resourced institutions. To introduce an authentic inquiry-based experience without increasing the monetary, time, or teaching resources needed, we converted an existing traditional laboratory exercise into an inquiry-based lab at California State University Dominguez Hills (CSUDH), a Hispanic- and minority-serving comprehensive university. This inquiry-based module allows students to use the scientific process while focusing on investigating factors influencing diffusion through a dialysis membrane. Students engaged in activities such as gathering preliminary data, formulating hypotheses, designing experiments, and analyzing results, which helped students to increase their self-efficacy. Although many inquiry-based labs have been adapted from “cookbook” type lab activities, this example uniquely discusses making these changes in an under-resourced, majority-minority university. Similarly designed modules that utilize existing resources and require minimal instructor expertise may be more accessible to a wider range of institutions, including those more similar to CSUDH, than traditional CUREs. We used a pre- and post-survey to demonstrate the efficacy of this approach in enhancing student understanding of scientific processes as well as increasing belonging among students from historically-minoritized groups. Here we provide insights and practical guidelines for incorporating inquiry-based labs in undergraduate biology education, particularly in under-resourced institutions serving diverse student populations.

Primary Image: Students were asked to plan an experiment to test a hypothesis based on diffusion through a dialysis tubing membrane. This group of students hypothesized that if they hydrolyzed starch using heat first, it would be able to move through the membrane. Although their hypothesis was not supported, they were able to complete a report including generating a figure. Student Figure Legend: FIG 1 Room Temperature Starch beaker contents & Heated Starch beaker contents. The Iodine Test shows a negative result/no reaction.

Citation

Kram KE, Eslami M. 2024. Adapting a Traditional Laboratory Exercise to Become Inquiry Based: An Example With an Introductory Biology Lab in Diffusion. CourseSouce 11. https://doi.org/10.24918/cs.2024.28

Society Learning Goals

Science Process Skills
  • Process of Science
    • Pose testable questions and hypotheses to address gaps in knowledge
    • Plan, evaluate, and implement scientific investigations
    • Interpret, evaluate, and draw conclusions from data
  • Communication and Collaboration
    • Share ideas, data, and findings with others clearly and accurately
    • Work productively in teams with people who have diverse backgrounds, skill sets, and perspectives
    • Provide and respond to constructive feedback in order to improve individual and team work
    • Reflect on your own learning, performance, and achievements

Lesson Learning Objectives

Students will be able to:
  • use the scientific method to develop scientific questions, form a hypothesis, design and perform an experiment, and analyze data to draw conclusions about the accuracy of their hypothesis.
  • create a figure to show data from an experiment.
  • work effectively as part of a team to complete a project.
  • evaluate their ability to use the scientific process effectively.

Article Context

Course
Article Type
Course Level
Bloom's Cognitive Level
Vision and Change Core Competencies
Vision and Change Core Concepts
Class Type
Class Size
Audience
Lesson Length
Pedagogical Approaches
Principles of How People Learn
Assessment Type

Introduction

Inquiry-based labs help students, especially those from minoritized-groups, develop self-efficacy (1, 2). Impacting student self-efficacy and sense of belonging is especially important for students who are less likely to be retained in the STEM-pipeline, but most published lessons for inquiry-based labs come from institutions where the majority of the students do not identify with these groups. Course-based undergraduate research experiences (CUREs) are often used to help students develop these skills (3, 4), however they can be difficult to implement at under-resourced institutions, or at institutions where the course may not be taught regularly by full-time faculty (57). For instance, at institutions like California State University Dominguez Hills (CSUDH), which is an under-resourced majority-minority comprehensive university, the labs are taught not by teaching assistants, but by faculty who are likely to have a heavy workload and who may be teaching the course for the first time or only teach the course once every several years. Budgets are often also restrained in a way that adding new materials, especially expensive materials required for molecular work, is difficult. However, students at these institutions still need authentic scientific experiences to increase self-efficacy and feelings of belonging. To add inquiry-based laboratory experiences at CSUDH we used the framework of short, multi-week experiments designed by students (8) to convert an existing traditional laboratory exercise into an open inquiry-based lab. Open inquiry, as opposed to guided inquiry, labs allow students to use background information to explore their own questions and hypotheses, as well as develop their own experimental methods to answer those questions (5). This type of inquiry helps students to develop their self-efficacy—they feel more like a “real scientist” as opposed to when they follow directions to get a known outcome (9, 10). Developing self-efficacy is important to keep students within the “STEM pipeline” (11). Conversions of “cookbook” laboratory exercises into inquiry-based learning opportunities, as demonstrated by Peres et al. (12) where students use simple resources such as avocados and lemon juice to understand the effect of pH on enzyme activity, or Crispo and Ilves (13) who used already existing animal specimen collections to answer quantitative questions about body morphology, require minimal or no new resources. However, these studies, like others (1416), primarily focus on student populations at well-resourced private universities and do not assess student self-efficacy. An exercise focusing on diffusion published by Taylor (17) required few resources and took place at a regional comprehensive university, but also did not assess self-efficacy. Rodríguez-Dueñas et al. described a laboratory exercise focusing on diffusion and osmosis at another under-resourced institution but aimed the experiment for engineering students who have significant mathematical knowledge (18). None of these exercises were developed at an institution where resources are likely very limited, and the majority of the students are from groups underrepresented in science, where such exercises may be the most impactful to student self-efficacy.

Overview of the Module

We converted a traditional lab focusing on diffusion through a dialysis membrane to an inquiry-based one, probing the factors that influence what types of molecules could diffuse through the membrane. The original lab also contained exercises focusing on different carbohydrates and how they can be detected using various reagents as well as hydrolysis of polysaccharides. During the new 3-week module, students first perform the traditional lab to gather preliminary data. Historically, at the end of the instructional period the instructor would explain the students’ results to them; in this redesign, students are instead asked to explain their observations. They are then asked to brainstorm hypotheses and how they might design an experiment to test their hypotheses. Finally, students write a protocol which they perform, and analyze their data to determine if their hypothesis is supported. We chose to redesign this module for several reasons. First, students tend to struggle with chemistry-based concepts, and we expected that a more inquiry-based approach would help students engage more deeply with these ideas. Second, as this module is the first module of the course, the straightforward nature of the experiments seemed like a good way to introduce students to the practice of forming scientific questions and hypotheses. Additionally, this module uses no new resources (materials or time) in laboratory preparation or new expertise for either the instructors or laboratory staff compared to the original traditional lab, which included fairly inexpensive and widely available materials (Supporting File S1), making it accessible to a wide variety of institutions.

Intended Audience

This module was designed for the first biology course in the majors’ introductory series (focused on cellular and molecular biology) at California State University, Dominguez Hills, a comprehensive Hispanic- and Minority-Serving Institution (HSI and MSI). Both biology majors and other biology-related majors take this course (kinesiology, clinical lab science [CLS], and biochemistry) at different points in their academic careers. The biology, CLS, and biochemistry majors are usually sophomores, whereas kinesiology majors may be seniors. The lecture and laboratory portions of the course are taken concurrently, however they are graded independently and not cohorted together, so the laboratory portion is self-contained. The pre-requisite for this class is an introduction to general chemistry course where the students have been exposed to laboratory experiments, but not inquiry-based labs. The laboratory sections (24 students each) are taught by both full-time and part-time faculty.

Required Learning Time

This module takes place during three laboratory sessions each consisting of a two hour and 45-minute meeting. Outside of class, students complete pre-lab quizzes each week that should take less than 30 minutes including both preparing for and completing the quiz. They may also need time outside of class to complete their end-of-module report, but many students can complete this during class time.

Prerequisite Student Knowledge

Because this is the students’ first biology course, very little prerequisite knowledge is required. During the module, the students are introduced to the concepts of: carbohydrates and polymers, hydrolysis/dehydration reactions, diffusion and osmosis, the scientific process (scientific questions versus general questions, hypotheses versus predictions, writing a protocol, controls, independent and dependent variables, etc.), and how to generate a figure and corresponding legend. Each of these concepts is the focus of a pre-lab quiz to ensure students are prepared for class. The biological content is presented at a surface level, as the students will go into more depth in the lecture portion of the class. As such we focus more on the scientific process and presentation of results in the laboratory course.

Prerequisite Teacher Knowledge

We tried to limit specialized knowledge needed by the instructor, since at our campus this course is taught by a variety of instructors including both full-time and part-time faculty. Instructors need to have a basic understanding of the biology concepts described above, as well as some techniques of active learning to encourage group work and brainstorming (19, 20).

Scientific Teaching Themes

Active Learning

Outside of class, students are expected to read or watch content and complete a pre-lab quiz to prepare for class. Students then perform hands-on laboratory experiments and analyze data in groups (both following directions and designing/performing their own). The students brainstorm questions, hypotheses, and protocols with feedback from their group members and their instructor. Because students design their own experiments, they should be more actively engaged in the process and the outcome (1, 5).

Assessment

There are multiple assessments during each module in the course. We use pre-lab quizzes as low-value summative assessments, post-lab worksheets as formative assessments (they are graded based on participation, but feedback is given before the final module report is turned in), and module reports, which represent high-value summative assessments. We encourage instructors to allow students to revise and resubmit these reports, but this decision is based on the instructors’ preference. Students use feedback on formative assignments to revise their module reports, as well as in-class discussions with both their peers and the instructor. Team evaluations are also used by both the instructor and students to assess group dynamics. These evaluations are given once mid-semester for formative feedback, and once at the end of the semester for summative assessment as a portion of each student’s grade. We used a survey to assess self-efficacy and other goals of the course design.

Inclusive Teaching

CSU Dominguez Hills is an HSI and MSI, with 79% of students belonging to historically minoritized groups in STEM. This allows instructors at CSUDH to have a large impact for students who traditionally may not see themselves represented in the STEM-field or as scientists (21, 22). Using open inquiry-based labs can help students, especially those from minoritized groups, see themselves as scientists and encourage them to continue in STEM fields (1, 3). Throughout the course we use scaffolding to ensure that students feel confident with each portion of the scientific process and communication. Our team evaluations were designed to not only assess contribution of team members but also factors like resolving conflict and encouraging others to participate. This course was implemented during the COVID-19 pandemic, and was taught as a fully online, synchronous course twice, and then as a mostly in-person course one semester (with five sections). The course objectives were achieved in both modalities (see Assessment and Teaching Discussion sections below). Offering online versions of laboratories can lead to higher inclusivity and success, especially of students from underrepresented backgrounds (23), so the ability to offer both modalities can also allow this type of inquiry-based lab to reach a larger number and wider variety of students and institutions.

Lesson Plan

Pre-Laboratory Preparation

This laboratory requires only equipment and chemicals that would normally be found in undergraduate biology labs. A full list of materials is provided (Supporting File S1). Prior to class, the solutions and reagents need to be made. Overall, this lab design uses fewer materials and needs less preparation than the previous design, because there is one week for hypothesis and experimental design where no materials are needed, as well as a repeat of the materials from week one during week three.

Students prepare for the lab using material posted on the learning management system (LMS) for each of the three weeks and by taking an online quiz before each class. The first week’s content focuses on carbohydrates and diffusion and is presented as written material (Supporting File S2). The second week’s content focuses on the scientific process: scientific questions, hypotheses, predictions, and experimental design including controls and variables. It is presented as written material (Supporting File S2) and as two sets of slides (Supporting Files S3, S4), which can be recorded over by the instructor if desired. The third week’s content focuses on figures in scientific writing and what needs to be included. It is presented as written material (Supporting File S2) and as an example figure (Supporting File S5), which the instructor can explain via video recording if desired. As this is the first module in the class, and this class is the first in the Principles of Biology series on our campus, this content is the base of the scaffold, which will be built up in later modules and courses.

Laboratory Exercise

A detailed lesson plan is described in Table 1. This module is broken down into three weeks: Week One is collecting “preliminary data,” where students use traditional laboratory exercises to observe how hydrolysis and dialysis work using various reagents. Week Two is for students to work together to determine their scientific question, hypothesis, and design their experiments. During Week Three, students carry out their designed experiments, think about their results, and determine if their hypothesis is supported.

Table 1. Lesson plan.

Activity Description Time Notes
Week 1
Advanced Preparation
Student preparation
  • Read background information

  • Take pre-lab quiz

  • Read protocol

~30 minutes
  • Post preview materials and quiz at least a week in advance

  • Make quiz due early enough to determine if there are any concepts to emphasize in pre-lab lecture

Solution making
  • Make solutions as detailed in Supporting File S1

~1 hour  
Day of Lab Set-Up
Reagent set-up
  • Set out labeled solutions

  • Set out test tubes, racks, dialysis tubing and clips, beakers, hot plates

~30 minutes
  • Can make one set per group, or ask students to distribute themselves

Laboratory Session
Pre-lab lecture
  • Brief lecture on group work (include roles within a group, discussion of team evaluations, and teamwork rubric)

  • Brief discussion of pre-lab quiz (if there were any sticking points include them here, ask if students had any other questions)

  • Brief introduction to the module and overarching question (How do molecules move through membranes?)

  • Explanation of materials needed for lab and point out where everything is located

~30 minutes
  • Can include a “protocol quiz” if desired

  • Discussion is brief to make sure students read pre-lab material

Experiments
  • Carbohydrate reagent test

  • Hydrolysis experiment

  • Dialysis experiment

~90 minutes
  • Students should have enough time to complete all three sets of experiments without needing to overlap, but they can if they choose

  • Can work on post-lab questions during incubation times

Post-lab worksheet
  • Students work in their groups to answer post-lab questions

  • If time, discuss answers as a class

~30 minutes
  • Students turn in post-lab worksheet at the end of class

  • Grade based on participation (if they did not complete, will need to by the end of the module for the report)

  • Feedback given

Week 2
Advanced Preparation
Student preparation
  • Read background information

  • Take pre-lab quiz

~30 minutes
  • Post preview materials and quiz at least a week in advance

  • Make due early enough to determine if there are any concepts to emphasize in pre-lab lecture

Laboratory Session
Pre-lab lecture
  • Brief discussion of questions remaining about last week’s lab

  • Brief discussion of pre-lab lab quiz

  • Brief discussion of outcomes for this lab

~15 minutes
  • Remind students that they need their experiments designed by the end of the lab so next week materials can be planned

Student discussion

Students work in their groups to identify:

  • Scientific question they want to answer

  • Hypothesis

  • Prediction

  • Experimental design, including control

~2 hours
  • Instructor gives active feedback during these discussions

Post-lab worksheet
  • Students work in their groups to answer post-lab questions

~30 minutes
  • This can be worked on during lab as instructor approves student work

Week 3
Advanced Preparation
Student preparation
  • Read background information

  • Take pre-lab quiz

  • Read their own protocol

~30 minutes
  • Post preview materials and quiz at least a week in advance

  • Make quiz due early enough to determine if there are any concepts to emphasize in pre-lab lecture

Solution making
  • Make solutions as detailed in Supporting File S1

~1 hour  
Day of Lab Set-Up
Reagent set-up
  • Set out labeled solutions

  • Set out test tubes, racks, dialysis tubing and clips, beakers, hot plates

~30 minutes
  • May vary per group depending on students’ designed experiments

Laboratory Session
Pre-lab lecture
  • Brief discussion of questions remaining about last week’s lab

  • Brief discussion of pre-lab lab quiz

  • Brief discussion of outcomes for this lab

~15 minutes
  • Remind students they should have everything they need for their module report at the end of this lab (and when it is due)

  • Make sure everyone feels comfortable with their protocol or if any adjustments need to be made

Experiments Students perform their experiment according to their protocol ~90 minutes  
Post-lab discussion

Students work together to determine:

  • If their experiment went as planned (Did their control work? Did their observations match their predictions?)

  • If their hypothesis was supported or not

Students work together to create a figure

~1 hour
  • Remind students that it is ok if their hypothesis is not supported, but should try to explain why they think it may not have been

Assessment
Module report (students) Students submit a module report which consists of the questions and post-lab worksheets throughout the module, as well as a figure Should be completed during class time See Supporting File S7
Grading (instructor) Module reports graded based on class structure ~15 minutes per report  
Revisions (students) Students can revise and resubmit their module report (not perform experiments again) based on instructor feedback ~1 hour This is optional

 

Week 1

The first week of the module consists of students performing multiple traditional lab exercises to collect data and answer questions that will help them to develop their hypothesis and design experiments the following week. The preview material for this week focuses on basic information about carbohydrates, including hydrolysis and dehydration reactions, diffusion, and osmosis (Supporting File S2). The protocols and questions with answers for the entire module are provided (Supporting File S2). The students perform three experiments to gather the preliminary data. The first is carbohydrate identification using multiple reagents. Students receive five tubes with different sugars (glucose, fructose, lactose, sucrose, and starch) and use three different reagents (Benedict’s, Barfoed’s, and iodine) to determine which reagents react with which sugars. Students are given a table to complete and asked to use online sources to identify information about each sugar (e.g., whether they are a mono-, di-, or polysaccharide and molecular weight) so they can think about what allows each reagent to react with different sugars. The second experiment focuses on hydrolysis. Students add HCl and/or heat to starch, and then add iodine to determine if starch is still present or if it has been hydrolyzed. This allows students to think about monomers and polymers, and that if a polymer is hydrolyzed, it no longer acts as a polymer. For the third experiment, students perform a traditional dialysis experiment by mixing NaCl and starch in dialysis tubing, placing the tubing in water for incubation, and then determining whether the NaCl and/or starch can cross the dialysis membrane (note: NaCl, detected by AgNO3, is able to cross the membrane while starch, detected by iodine, cannot). Questions and class discussions help students interpret these results and encourage them to start thinking about why NaCl can move through the membrane and starch cannot.

Since this is the first module in the course, this week’s activities also allow students to begin to learn about controls in experiments, which they will apply in the following week when designing experiments. It is also the first time the students work together with their groups to complete tasks and answer questions, so it is important to encourage discussion among group members. In this course, groups of 3–4 students were formed based on where students sat on the first day of class and were kept the same the entire semester. During the meeting, students work to complete their “post-lab worksheet” which is due at the end of class (see Assessment for details) (Supporting File S2). Depending on timing and instructor preference, they can either go over questions together as a group, post the answers, or rely on individual feedback. The goal of these questions is to (i) ensure the students understand the observations they made and can interpret them correctly, and (ii) have the students begin thinking about possible explanations for the differences observed during dialysis.

Week 2

The goal of the second week of the module is for students to use the information from the previous class to develop a hypothesis regarding what property determines whether a molecule can move through a dialysis membrane, and then design an experiment to test their hypothesis. The preview material for this week focuses on the differences between non-scientific and scientific questions, hypotheses, and predictions, as well as general experimental design including the importance of controls (Supporting Files S2–S4). We also discuss independent and dependent variables. Students should work together to have an experiment designed by the end of the class period so that any additional set-up needed for the following week can be completed. As this is the first time many of the students are asked to come up with their own scientific question, hypothesis, and experiment, they will need significant guidance and supervision. We provide them with guiding questions (Supporting File S2) to help stimulate their thinking process. We also tell them their experiment should look similar to the dialysis experiment in Week One and that they will have access to the same materials. We ask the students to come up with their scientific question and hypothesis first, which is approved by the instructor, then they move on to their experiment and predictions. To manage expectations, we tell the students to expect they will need multiple iterations of their questions, hypotheses, and protocol, and sometimes if students really struggle, we give some examples from other groups. We also ask students to identify their dependent and independent variables, as well as their control.

In the semesters where we used this module, many students focused on size as their independent variable, since they may have learned previously that size affects movement through membranes, or they may have just observed that NaCl is a smaller molecule than starch. Based on this idea, students will often decide to add glucose to their dialysis tubes instead of NaCl, since it is also significantly smaller than starch. Other independent variables students wanted to test included temperature, polarity, or chemical bond (since NaCl is an ionic compound and the bonds in starch are covalent). We help students make sure their independent variable is clear in their question and hypothesis, and that their question and hypothesis are in the correct format. We also help them make sure their experimental plans will actually test their hypothesis, and that their experiment is doable with the reagents and materials available. However, we do not steer students to make sure their hypothesis will be supported or to the “correct” variable, which in this case is the size of the molecule.

Week 3

During the third week of the module, the students perform their experiment, analyze their data, and make conclusions about whether their hypothesis was supported. They also use their data to create a figure, including a legend, which is the focus of their pre-lab material (Supporting Files S2, S5). Before students begin, we make sure their experiments are clear and give them the opportunity to adjust (for instance, they may need to adjust a temperature based on incubator availability). We direct the students to create a table for their observations if they did not create it during the previous week. Once they complete the experiment, the students interpret their observations, determine if their experiment went as planned (including their control), and decide if their hypothesis is supported. Students often feel discouraged if their hypothesis is not supported, or they believe it indicates a mistake on their part. We remind that in science, it is common for hypotheses to be incorrect or unsupported by data, and they will be evaluated on their interpretations, not the outcome. This helps students start to form their identity as scientists and learn that being a science student does not mean they always have to be correct (3, 911).

Assessment

Both formative and summative assessments are used during the module. The pre-lab quizzes are a low-stakes summative assessment to encourage students to read or watch the material that will help them prepare for class (Supporting File S6). These are given as a quiz on our LMS or embedded into videos but could also be given in person at the beginning of class. The quizzes were designed to be open-note, so students are encouraged to use their preview materials. We gave the quizzes without the opportunity for re-takes, but they could also be used as formative assessments with re-takes. Students had formative assessments in the form of a “post-lab worksheet” (Supporting File S2) each week. Each instructor can decide if the worksheet can be submitted individually or as a group—group submission lessens the grading load, but individual submission is more likely to ensure participation from each student and/or allows for more direct observation if individual students are struggling with the material. These worksheets ask questions that help the students understand the activities in class. Students receive participation points for turning the worksheets in at the end of class and receive feedback on the answers. This gives students the opportunity for further understanding, and to correct wrong or incomplete answers before turning them in for the final time.

The major summative assessment for the module was the “Module Report.” A report template with answers, along with several example reports, is provided (Supporting File S7, S8). This module was completed during online instruction, and so the instructor sent the students images of their “results.” In-person, students can observe and take pictures of their results to include in their report. The module report combines each week’s lab observations and post-lab worksheets. It is turned in as a group and each student receives the same grade. This report helps the students to summarize the entire experiment, starting with preliminary observations, experimental design, and final conclusions. They can incorporate feedback from previous weeks’ formative assessments and work as a group to answer questions about the topic covered by the module. We would encourage instructors to allow revisions of the module report at least once during the term.

Teaching Discussion

We designed this lab as part of converting many of our laboratory classes to be more inquiry-based. This lab is the first in a series of four lab modules in this course, which is in turn the first in the introductory biology series, each of which now include inquiry-based experiences. While this module includes content goals regarding diffusion through membranes and carbohydrate structure, it also introduces the concept of scientific inquiry to students in their first college-level biology course. One of the main goals of these redesigned courses is for more students to engage in the scientific method and understand how scientific questions, hypotheses, and experimental design connect to each other. We assessed both their confidence with the scientific process and their feelings on self-efficacy and belonging using a pre- and post-survey (Supporting File S9; IRB approval: 21-005). In Figure 1, we show the pre- and post-survey results as alluvial plots, where individual student responses are tracked. The possible responses are listed in the boxes on the sides, and the height of the boxes correspond to the percentage of students who chose that answer. Each student’s pre-survey answer is marked on the left side of the plot, and their post-survey answer is on the right side of the plot. The lines show movement between a student’s response on the pre-survey, and then flows to their response on the post-survey. For instance, if a student who answered “some” to the question displayed in Figure 1A on the pre-survey and “extensive” to that same question on the post-survey, they would be included in the second peach-colored line. If a student answered the same way on the pre-survey but kept their answer as “some” on the post-survey, they would be included in the second blue-colored line. Any student who did not respond to both the pre- and post-surveys were removed from the dataset, which left 109 student responses for analysis. These responses were collected over three semesters and include data from five different instructors.

When asked about their experience with experimental design, we found that in this course (which includes this module, and three additional similarly designed modules) students’ agreement with statements about their level of experience with collecting and analyzing data increased (Figure 1A and 1B; p value < 0.001 in Mann-Whitney statistical test for both statements). We also found that students felt their level of experience with a lab or project where students have some input into the research process increased (Figure 1C; p value < 0.001 in Mann-Whitney statistical test), which may help them feel more like an actual scientist than completing a lab based on a given protocol alone (1, 5). Interestingly, one of the questions we expected to see a large difference in, “Give an estimate of your current level of experience for: Presenting the results in written papers or reports.” did not change significantly (p value = 0.067 in Mann-Whitney statistical test), even though students wrote reports for each of the four laboratory modules in the course (data not shown). This may be due to students coming into the class feeling comfortable writing lab reports from their pre-requisite introductory chemistry course, however these lab reports are different than the ones expected in biology courses generally. These data indicate that more emphasis on writing their results in the specific way we want them to in their biology courses could be helpful, since this is one of the main skills we would like students to feel comfortable with after their laboratory experience.

At CSUDH, as well as across the country, many students leave STEM fields early in their college education (24, 25). This is especially true for students from historically minoritized groups, such as Hispanic/Latino and Black/African American students (24, 25). Because CSUDH’s student population is mostly these students (66% Hispanic/Latino and 11% Black/African American for Fall 2022 enrollment), we are in an excellent position to address this issue. One problem that can lead students to leave the STEM pipeline is when they do not see themselves as scientists or feel like they do not belong (26). By asking the students to design and perform their own experiments, we expected they would increase their sense of belonging and capabilities as scientists (11, 27). After this course, we found students increased their agreement with the statement “I can help others in this class learn” (Figure 1D; p value = 0.006 in Mann-Whitney statistical test) indicating their self-efficacy in communicating biological ideas to their classmates increased. Students also increased their agreement with the statement “The students sitting near me respect my opinions” (Figure 1E; p value < 0.001 in Mann-Whitney statistical test) which indicates students have increased their sense of belonging among their peers.

Potential Challenges

There were several challenges faced by instructors, lab staff, and students during the development and execution of this module. The main challenge for the instructors was that many were guiding students in designing and performing their own experiments for the first time. Additionally, many faculty felt it was important for students to arrive at the "right" hypothesis or for their experiments to "work correctly" so that students would better understand the concepts of diffusion and osmosis. In our case, we knew that students would learn how diffusion and osmosis work in lecture classes, and that even if their original hypothesis was incorrect, the act of thinking about it would still improve their understanding. Further, we viewed the gains in self-efficacy and process skills as more important than the biology content. However, if this was a concern it could be addressed by giving the students more information about how diffusion works and then asking them to design experiments to confirm that size is the important independent variable in this set-up, which would still require students to make predictions, come up with a protocol, and interpret their data. On the other hand, this module could also be expanded to be more iterative (see below) so that students eventually conclude that size is the important factor for diffusion in this case.

The lab staff were mainly concerned about keeping the preparation for each lab section the same, and that if students were given the ability to come up with any experiment this would create a lot more work for their already-stretched team. We addressed this issue by narrowing the list of materials to those used in the first week of the lab and telling students these restrictions before they designed their experiments. The instructors helped ensure that the student experiments could be performed with the materials available and within the allotted lab period.

The main student struggle was that often their hypotheses were unsupported, or their experiment did not work as planned. This was especially difficult for students who only had experience with more “cookbook” labs, where their grade depended on the results they found because a “wrong” answer indicated they had done something incorrectly. We countered this in two ways. First, we did not assess them on whether their hypothesis was supported or if their experiment worked, but on how they interpreted their data or on how they suggested to adjust their experiment in the future. Therefore, even students with no data could get full credit for the module report, which instructors relayed to the students. Second, we discussed with students that scientists are wrong frequently, with some instructors even using examples from their own careers, and that this is a very normal part of the scientific process. These discussions potentially help students think of themselves as a scientist and increase their understanding that being a good scientist does not mean getting everything “right” on the first try.

Although there was some heterogeneity between sections with how successful the instructors were at getting these messages across, the statistical analysis, which was performed on all sections together, shows that the design of these labs is robust to this variation for many of the outcomes we were evaluating.

Potential Modifications

This module could be modified in any number of ways. It could be narrowed by only including the dialysis experiment on Week One, for example, especially if students already had exposure to carbohydrate testing. It could also be lengthened to expand on the scientific process by allowing the students to refine their hypotheses based on their data and perform a new experiment. This type of iteration could be especially useful to increase the self-efficacy gains we already see here. The framework can also be applied to any number of topics—we used the same framework to create labs based on enzyme function, the cell cycle, and central dogma.

This module was designed during a virtual learning-only semester as required due to the COVID-19 pandemic, and there are minimal differences between the in-person and online versions. Therefore, inquiry-based learning can be incorporated even into virtual classrooms. The online version of the class was held during synchronous meetings where students could “observe” the results of experiments and continue to work together in break-out rooms. In the online version, groups were formed based on a survey asking how committed they were to come to each class period, if they were planning to turn on their cameras, how strong their math and chemistry backgrounds were, and their major. Diverse groups of 4–6 students were formed based on the survey answers. For the first week, images of the results from the experiments were posted on the course’s LMS. Because the module focused on science processes, the learning objectives could still be achieved even if students did not do the wet-lab procedure themselves. In this version, we did require students to submit the post-lab worksheets individually to ensure everyone was participating, because participation was generally more difficult to observe online. During the second period, we used shared Google Docs to observe students develop their scientific questions, hypotheses, and methods for their own experiment. The instructor went to each group in a break-out room and discussed their plans, similar to what they would do in the classroom. Then, for the third week, the instructor created images of the “results” of the students’ planned experiments. If the students’ written plan would have resulted in no data or flawed data, this would be reflected in the results for each group. The main positive aspect of receiving results virtually was that students could see immediately if their protocol was flawed, work to address the issues, and then the instructor could easily send them new “results” based on their updated protocol. Although it would be more difficult to address teamwork-focused learning objectives, the course could also be modified for asynchronous learning, as long as the instructor could give feedback and “results” to each student individually (perhaps with more guiderails on the experimental design, like specifying only a few materials they could use).

In larger classes or classes that need a more standardized procedure, students could come up with experimental designs and then the entire class could choose one and everyone could perform the same experiment, allowing for replication while having a more standardized lab set-up.

Supporting Materials

  • S1. Diffusion Inquiry Lab – Materials Needed

  • S2. Diffusion Inquiry Lab – Module Handout [Instructor view only]

  • S3. Diffusion Inquiry Lab – Questions vs. Hypotheses

  • S4. Diffusion Inquiry Lab – Experimental Set-Ups

  • S5. Diffusion Inquiry Lab – Sample Figure

  • S6. Diffusion Inquiry Lab – Pre-Lab Quizzes [Instructor view only]

  • S7. Diffusion Inquiry Lab – Module Report Template [Instructor view only]

  • S8. Diffusion Inquiry Lab – Example Module Reports [Instructor view only]

  • S9. Diffusion Inquiry Lab – Post-Class Survey Questions

Acknowledgments

We acknowledge funding from the California Education Learning Lab grant OPR19187. We would also like to thank CSUDH laboratory staff Sandy Lin and Annette Rodriguez, as well as the other CSUDH faculty members who taught this course: Eillen Tecle, Artin Soroosh, Kahung Lee, and Stacy Zamora. We would also like to thank Brian Sato and Sonal Singhal for help with the manuscript.

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Article Files

to access supporting documents

  • pdf Kram-Eslami-Adapting a Traditional Laboratory Exercise to Become Inquiry Based An Example With an Introductory Biology Lab in Diffusion.pdf(PDF | 1 MB)
  • docx S1. Diffusion Inquiry Lab - Materials Needed.docx(DOCX | 16 KB)
  • docx S2. Diffusion Inquiry Lab - Module Handout Instructor view only.docx (Instructors only)(DOCX | 6 MB)
  • pptx S3. Diffusion Inquiry Lab - Questions vs. Hypotheses.pptx(PPTX | 65 KB)
  • pptx S4. Diffusion Inquiry Lab - Experimental Set-Ups.pptx(PPTX | 69 KB)
  • pptx S5. Diffusion Inquiry Lab - Sample Figure.pptx(PPTX | 2 MB)
  • docx S6. Diffusion Inquiry Lab - Pre-Lab Quizzes Instructor view only.docx (Instructors only)(DOCX | 17 KB)
  • docx S7. Diffusion Inquiry Lab - Module Report Template Instructor view only.docx (Instructors only)(DOCX | 24 KB)
  • pdf S8. Diffusion Inquiry Lab - Example Module Reports Instructor view only.pdf (Instructors only)(PDF | 1 MB)
  • xlsx S9. Diffusion Inquiry Lab - Post-Class Survey Questions.xlsx(XLSX | 12 KB)
  • License terms

Authors

Author(s): Karin E. Kram*1, Maryam Eslami2

1. California State University, Dominguez Hills 2. University of California, Irvine

About the Authors

*Correspondence to: kkram@csudh.edu, CSUDH 1000 E. Victoria St., SCI 211, Carson, CA 90747 

Competing Interests

Funding: California Education Learning Lab (OPR19187). None of the authors have a financial, personal, or professional conflict of interest related to this work.

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