Category: Labs

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Science or Not Lab: Experimental Design

Why are larger individuals of a particular species eaten more frequently than smaller ones?

Overview

The primary purpose of this investigation is to introduce students to 1) the collaborative process and guided inquiry format that will be used in each investigation, 2) the lab preparation and reporting assignments, and 3) resources available for help (lab manual and faculty instructor/peer mentors). As an introduction to the lab, this investigation thus differs from the others in that the hypothesis to be tested is provided to students: “Larger Catocala moths are eaten more often than smaller ones because the larger ones are easier to see.” As in each investigation, background information is presented to help frame the direction of inquiry. Foraging theory and prey crypsis are used to motivate the provided hypothesis.

Outcomes: Inquiry 5, Inquiry 6, Inquiry 7, Inquiry 8

Materials

Lab-Aids Natural Selection Experiment (Kit #91). Provide one per group of students.

Shaw, T.J. & French, D.P. (2018). Authentic Research in Introductory Biology, 2018 ed. Fountainhead, Fort Worth.

Timeline

We suggest two weeks for this investigation if it’s the first lab investigation of the term.

Week 1:  Begin planning form

  1. May submit by end of lab period, or in LRC
  2. Will complete as a group, not individually (all other planning forms are individually completed)

Week 2:  Conduct experiment and compose lab report

Assessments

Quiz

Keys and additional instructor-only notes (you will be asked to sign into a Google account and request access to view instructor materials)

Lab report rubric

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(I think this is a key for the Drive) Investigation A: Instructor-only notes

  1. Briefly describe the Lab
    1. Students will be working in groups
    2. They will learn by doing
    3. Each week is a new investigation.  For each investigation there will be background information and a question posed.  They will design and conduct an experiment that addresses the question.
    4. Prior to lab, students will read the investigation and prepare for lab by completing that week’s planning form and pre-lab activities.
    5. Encourage equal participation.  Lack of participation from a student can significantly reduce their grade!
  2. Introduce the Lab Manual
    1. Each student needs to have his or her own manual.  They need to bring it to lab every week. Point out the three different sections:
      1. Guide to Success: Includes general information about the course, how to conduct a lab, write a report, etc.
      2. Reference: Includes instructions on how to use equipment and software for lab experiments.
      3. Investigations: background information, terms, pre-labs, planning forms, etc. for each lab.
  3. Planning Forms
    1. Instead of telling students about planning forms, it is most beneficial to discuss them as students do them.
      1. Have students turn to the first investigation.  Point out the question under investigation, background information, pre-labs, terms/concepts of interest, special equipment sections.
      2. Go through the first page of the planning form.  Allow students to work in groups to formulate responses, then discuss what would be appropriate.  This weeks’ hypothesis is provided (“Larger moths are eaten more often than smaller ones because they are easier to see.”) but you will want to encourage discussion about developing a hypothesis now because students will do it on their own in the future.
      3. Discuss experimental design with a control and experimental groups.  Ensure that the students have a good understanding of independent and dependent variables so that they may construct graphs properly.
      4. Students are expected to complete the Preparation Checklist (on the backside of the planning form), but only A-C are required. Students can keep D blank.  
      5. Emphasize that planning forms are expected to be completed individually, but this week, they’ll be completed as a group.  This would be a good time to contrast collaboration and plagiarism.
  4. Investigation
    1. Aside from the basics of designing and conducting an experiment, and writing a lab report, you will want to encourage students in the following areas:
      1. Developing a testable repeatable experiment.  Remember that the moth is in its “natural” habitat.  Removing the pieces from the box to make them easier to see may not provide information that will help the scientist in the background who is working in the field with “live” colonies and predators.  Students don’t often realize that to make something harder to see, they can just close their eyes!
      2. Appropriate controls.  How large is large? How small is small?  Can you assume that all Catocala colonies contain the same number and sizes of individuals?  Is experimenter bias something to be concerned about? What about hand size of the predators?  Will the moth be replaced after each sample, or at the end of a trial? Do students think the predator selects prey one at a time, or by the handful? These are all things for students to think about, but having to consider all of these questions at once can overwhelm students and make them feel like the investigation is impossible.  

Additional resources

Quiz

Key

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Sea to Shore Lab: Thermoregulation

Why are animals shaped differently in cooler climates than in warmer ones?

Overview

The purpose of this lab is to get students relating surface area/volume ratio to the way in which an animal thermoregulates (by using modeling clay).  At the conclusion of this investigation, students should also be writing a better lab report, able to produce a XY scatter plot with a trendline, and perform a simple statistical test. They will be using modeling clay to simulate body shapes, and temp probes to monitor any changes.  They may craft any shape they like, provided that 1. They can calculate the SA/V ratio of the shape, and 2. They can accurately record its temp with the probe (shapes like a long cylinder or flattened box do not work well as there is little clay surrounding the temp probe).

Outcomes:  Inquiry 4, Inquiry 5, Inquiry 6, Inquiry 7, Inquiry 8; SA/V 1; Gradients 1, Gradients 2, Gradients 3, Gradients 4; Thermoregulation 1, Thermoregulation 6

Materials (Per lab group)

Shaw, T.J. & French, D.P. (2018). Authentic Research in Introductory Biology, 2018 ed. Fountainhead, Fort Worth.

Assessments

PreLab

Quiz

Keys and additional instructor-only notes (you will be asked to sign into a Google account and request access to view instructor materials)

Lab report rubric

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Sea to Shore Lab: Diffusion

Why is diffusion through a membrane sometimes faster?

Overview

This lab should help students understand the extremely important role of gradients. Focus on the idea that gradients occur whenever there is a concentration difference from high to low. Gradients do not just occur in liquids there can be gradients in temperature, Na and K ions, smoke, perfume, people, etc.

Students should be familiar with the terms solute, solvent, hyper-and hypotonic. Osmosis refers to the movement of water and dialysis typically to the movement of solute. Students may or may not comprehend the concept of ion, but you can simply leave it as a charged atom or particle or molecule. Unfortunately, if they don’t have some clue about ions or at least that NaCl becomes Na+ and Cl- when dissolved, the understanding what conductivity tells them is difficult. The pre-lab explains it, but be prepared.

Outcomes:  Inquiry 4, Inquiry 5, Inquiry 6, Inquiry 7, Inquiry 8; SA/V 1, SA/V 2; Gradients 1, Gradients 2, Gradients 3, Gradients 4; Membrane Transport 2, Membrane Transport 3, Membrane Transport 5

Materials

Per lab group

Shaw, T.J. & French, D.P. (2018). Authentic Research in Introductory Biology, 2018 ed. Fountainhead, Fort Worth.

Assessments

PreLab Activity

Quiz

Keys and additional instructor-only notes (you will be asked to sign into a Google account and request access to view instructor materials)

Lab report rubric