Biology Bacteria Inquiry Lab  

Group Members Names:        

Background: Bacteria have been found nearly everywhere on earth in a wide variety of environments (soil, hot springs, waste, indoors, water, your skin, and in the earth’s crust). Bacteria make-up the group of single celled organisms called prokaryotes.  To examine and compare bacteria in our local community your group will be collecting, incubating (growing), and observing bacteria.

Instructions:  Your lab team will form a question and hypothesis about bacteria found at school and then create an experiment to answer your question.  You will have 20 minutes to collect bacteria and 2-3 days to allow your culture to grow.  (Your experiment therefore must be for something that is testable in the amount of given time.)

In the space below form a question, hypothesis, variables and procedure.  You must have this section checked before collecting bacteria.  Below are some materials you can use, and your teacher will demonstrate how to set-up you petri plate into quadrants so you can collect data.  

Safety Considerations: Wash hands often.  Tape your petri plate closed after collection and do DO NOT REOPEN IT - you could have collected harmful bacteria.  Use bleach buckets to dispose of reusable equipment. Disinfect counter tops after all activities.

MATERIALS AVAILABLE:

  • Agar plates (petri dishes with a food like culture)
  • Cotton swabs
  • Bleach buckets for disposal

  • Masking tape and marker
  • Incubator (warms the plates to encourage bacteria to grow)

DIRECTIONS:

Part A:

  1. As a team write a testable question that outlines what you want to examine below the following example.

Example: Does drinking two cups of coffee every school day morning create an improvement in 1st period test scores?

  1. Complete the variable table below:

Table 1.  Bacteria Inquiry Lab Variables

Types of Variables

Variables

Independent Variable (IV): The part of the experiment you will change (include them here).

Dependent Variable (DV):  The part of the experiment that will change as a result of the IV.  

Control Test: What the IV will be compared to in order to know the change was due to your test, and not some random variable.

Constant Variables: What will remain the same during the experiment that the other variables can be compared to

  1. Write a hypothesis for your experiment in the following format:

If (insert planned change in independent variable here), then (predicted change in dependent variable).  The why or because can also be included. 





Part B:

  1.  Prepare the petri plates:
  1. Without opening the petri dish, use a marking pen to divide the dish into four quadrants & label them on the bottom of the petri dish (Lids are not labeled because they can easily fall off or be mixed up).
  2. Identify three surfaces your group would like to test & one control:



  1.  Using a sterile cotton swab, rub the swab over the surface of the item.  Rub the cotton swab on an unused quadrant and record the surface for each quadrant in your data table.

  1. Complete the first column of Table 2.  

Table 2

Objects Tested/Location

DV Measurement/ units:              

Qualitative Observations

Quadrant 1

Quadrant 2

Quadrant 3

Quadrant 4 (Control)

  1. Record data collected from your observations in Table 2.

Part C:

The following will be completed after bacteria plates are incubated and analyzed.

  1.  Collect and organize your data and observations with your group and create a graph to visualize your results. Insert your graph below (Here is a video that tells you how to insert your graph).

  1. Write a conclusion that completes the following components. DO NOT ANSWER THESE AS QUESTIONS, WRITE A SEPARATE PARAGRAPH
  1. Restate the hypothesis and describe if it was confirmed or contradicted.
  2. State the answer to your question.
  3. Explain your results using data and the graph made in #7.
  4. Describe procedure errors and any limitations or observed mistakes that influenced your results (do not state human error)
  5. Describe modifications to improve the experiment procedure and future topics of study
  6. Connect your findings to the real world or other studies.

Insert your conclusion below.

 

Exceeds (4)

Meets (3)

Nearly Meets (2)

Beginning (1)

Experiment Question & Variables

❑  Fully relevant and testable question & numerical hypothesis that clearly articulates

numerical expectations of the experiment

 

❑  Fully appropriate multiple factor IV, appropriate DV, constants & comparable control

❑ Considers numerous  factors that may influence the precision of collected data

❑ Testable question and hypothesis with numerical expectation of experiment

❑  Appropriate IV, DV, control and multiple appropriate constants

❑ Considers some factors that may influence the precision of collected data

❑  Question and/or Hypothesis is  unclear, contains errors, or is not numerical


❑ Incorrectly identifies IV, DV, Control, or does not state at least two appropriate constants

❑ Question and/or hypothesis is not stated or not testable

❑ Does not include an  IV, DV and/or Control and states less than two appropriate constants

Experiment Procedure & Background:

❑  Entirely appropriate procedure allows for the collection of sufficient data to perform extensive analysis of experiment hypothesis

❑  Background is fully relevant and enhances the understanding experiment context

❑ Clear, repeatable procedure that provides for the collection of sufficient data to assess hypothesis

❑  Background describes purpose of the experiment

❑ Procedure is not entirely clear, repeatable or does not yield sufficient data to assess hypothesis

❑ Background lacks detail to identify purpose of investigation

❑ Procedure is absent, unclear, or missing multiple steps to yield any data

❑ Background is missing or has no relevance to experiment

Experiment Evaluation:

❑  States hypothesis with explanation that is fully justified with experimental data

❑  Identified specific procedure limitations and suggests improvements to increase the quality (precision) of experimental data collected

❑  Applies experiment to relevant associated topics and original questions & hypothesis with cited credible sources

❑  States hypothesis with explanation and supported with experimental data

❑ Provides discussion of procedure limitations and ways to improve

❑ Summarizes experimental results as related to original question & hypothesis

❑States a hypothesis and explanation that does not include support with experimental data

❑ Provides minimal discussion  of procedure limitations and/or no discussion of  improvement

❑ Limited connection of findings to original question or hypothesis

❑ States no explanation or no support of hypothesis

❑ Provides no identification of procedure limitations

❑ No connection of findings to original question


 

Exceeds (4)

Meets (3)

Nearly Meets (2)

Beginning (1)

Data Analysis

❑ Data tables are appropriate and include correct title, units, data and calculations to support valid experiment conclusions

❑ Analysis of data includes appropriate calculations: mode, average, error or uncertainties

❑ Graph type clearly illustrates data trend(s)

❑ Data table(s) are appropriate and include correct title, units and data to support experiment conclusions

❑ Type of graph is appropriate to  illustrate data trend(s)

❑ Labeling of graph is correct (axis, units, legend, and title)

❑ Data table(s) is missing appropriate title, units or data

❑ Type of graph is not appropriate to illustrate data trend(s)

❑ Labeling of graph is not correct (axis, units, legend, or title)

❑ Data table is illegible or not present

❑ Graph is not present

Communication

❑  Appropriate technology tools used to collect, process and report experimental results

❑  Facilitates ready understanding of purpose, process and experimental outcomes in relation to related concepts

❑  Well structured & clear with extensive use of appropriate scientific vocabulary to support conclusions

❑  Appropriate technology tools used to collect, process and report experimental results

❑  Presented information provides clear understanding of purpose, process and experimental outcomes

❑  Clearly structured with appropriate use of scientific vocabulary

❑ Mistakes or use of technological resources requires significant assistance.

❑ Presented information contains errors or mistakes that create unclear purpose, process and experimental outcomes

❑  Not well structured and/or errors in vocabulary detract from presented understanding

❑ Does not use tools tools to collect, process and report experimental results

❑  Many errors or disorganization in structure and vocabulary