IB Exploration Practice 1 - DNA
The careful design of an experiment and identification of variables is crucial to the successful collection of data. IB specifically designates three aspects (selecting variables, controlling variables, and procedural methods) included in the design portion of an experimental investigation.
To practice completing the Design Standard and corresponding aspects, you will work with other students to create a experimental investigation to assess the DNA extraction protocols used in the DNA Extraction Lab Protocols.
This means your group will be designing an experiment (but not conducting) to test the effect of changing the selected protocol on the either the quantity or quality of DNA extracted, i.e. you will decide on variables to alter in order to attempt to improve the quantity or quality of DNA extracted. Only one overall experimental Design is required per group for only one of DNA extraction protocols.
Defining the Research Question:
In this practice, you will be working on the following basic question: How does __________ affect the yield/quality (you pick one) of DNA extracted from ____________?
Define is a command term that means to give a precise meaning of a word, phrase of physical quantity. It is sometimes helpful with a definition to provide an example if possible.
- Define precisely the term "yield" or “quality”.
- Define precisely what will be tested.
- Define precisely what will be measured
Rewrite the problem statement as a research question. Use the precise meanings you have developed. From this, write a testable, specific and detailed hypothesis.
Outlining the Procedure & Stating Variable
The command term outline requires you to give a brief outline or summary, while state asks you to give a specific name, value or other brief answer without explanation or calculation. Describe requires you to give a detailed account.
- Outline the experiment you would do to test your problem statement.
- State your independent (manipulated) variable and describe how it is varied between the two sites.
- State your dependent (responding) variable. Describe how you will measure it.
- State any controlled variables in your experiment and describe how they are going to be held constant and how you will monitor them.
Example Format of Design Write-Up
- Experiment Title
- Research Question
- Background (Not necessary for this activity)
- Independent Variable
- Dependent Variable
- Method of Controlling Variables
- Suggested to outline means of controlling each variable (make a list bullet style)
- Materials (Not necessary for this activity)
- Include a clear discussion of how data will be collected and predicted observed results
- Indication of number of trials and justification for this number
- Safety Concerns/Precautions
Create one google document for your group with all members names on the document. Only the owner will be able to turn in the document on Google Classroom, each other member can mark the assignment as done when complete.
This criterion assess the extent to which the student establishes the scientific context for the work, states a clear and focused research question and uses concepts and techniques appropriate for the Diploma Program level. Where appropriate, this criterion also assesses awareness of safety, environmental, and ethical considerations.
- The topic of the investigation is identified and a relevant and fully focused research question is clearly described.
- The background information provided for the investigation is entirely appropriate and relevant and enhances the understanding of the context of the investigation.
- The methodology of the investigation is highly appropriate to address the research question because it takes into consideration all, or nearly all, of the significant factors that may influence the relevance, reliability and sufficiency of the collected data.
- The report shows evidence of full awareness of the significant safety, ethical or environmental issues that are relevant to the methodology of the investigation.
- The topic of the investigation is identified and a relevant but not fully focused research question is described
- The background information provided for the investigation is mainly appropriate and relevant and aids the understanding of the context of the investigation
- The methodology of the investigation is mainly appropriate to address the research question but has limitations since it takes into consideration only some of the significant factors that may influence the relevance, reliability and sufficiency of the collected data
- The report shows evidence of some awareness of the significant safety, ethical or environmental issues that are relevant to the methodology of the investigation*
Nearly Meets (2)
- The topic of the investigation is identified and a research question of some relevance is stated but it is not focused
- The background information provided for the investigation is superficial or of limited relevance and does not aid the understanding of the context of the investigation
- The methodology of the investigation is only appropriate to address the research question to a very limited extent since it takes into consideration few of the significant factors that may influence the relevance, reliability and sufficiency of the collected data
- The report shows evidence of limited awareness of the significant safety, ethical or environmental issues that are relevant to the methodology of the investigation.
The student’s report does not reach a standard described by the descriptors above.
Exploration Further Explanation:
- Background: Just like a history or english paper, scientific research/lab reports have an introduction, referred to as a background. The background should be a paragraph or two that explains why the experiment is relevant (to both biology and life), discusses what process or mechanism will be experimented, and includes background information necessary to understand the scope of the experiment. The background should include cited sources (use a separate works cited page) for background information pertaining to the topic at hand.
- Research Question: A single sentence that specifically states the objective of the investigation.
- Variables: Variables must be specifically identified and explained why relevant. Variables that will be manipulated (independent), those that will respond to manipulations (dependent), and those that are not manipulated (control) must be identified.
- Hypothesis(es): The hypothesis(es) should be composed to identify the analysis of the relationship between two or more variables; ‘If independent variable(s) is manipulated, then prediction to dependent variable.” It should be assumed, but they hypothesis must be directly related to the question of research.
- Create a list of experimental materials/apparatus. Be specific.
- If selecting a quantity to use during the course of the experiment, justify the quantity you select.
- A description of how the experiment will be set up; this should be supplemented by diagrams, sketches, or photos to illustrate the procedure.
- List the means that the experiment will be conducted using a detailed numbered list. The procedure should include sufficient detail so that anyone reading your work could repeat your experiment.
- Routine actions, such as using a thermometer to check the temperature does not need to be explained but can be simply stated.
- If a standard technique is used, this can be used and referenced to as part of the procedure as long as a citation of the source is provided.
- If an action is completed to minimize anticipated error, discuss this as well.
- Clearly state how data will be collected and what anticipated qualitative observations you anticipate.
- All conditions that could affect the outcome of the experiment must be controlled for or removed except for the independent variable. This ensures that all results and data collected are directly due to the independent variable.
- This should be accomplished by a paragraph that explains how variables will be controlled and a description of procedure or method for controlling each variable. For example, if the salinity of a solution is to remain constant throughout the duration of a test, the salinity values could be tested before and after the collection of data.
- The procedure must provide for sufficient collection of data to complete analysis of results. Sufficient data is a rather vague term, but a safe conclusion is to perform multiple trials unless the experiment time frame is multiple months/year(s). A good rule of thumb is five measurements for a lower limit and 20 measurements on the high end. At minimum, you should use 5 different variants of your independent variable and 5 trials for each variant,
- If one of your trials is significantly different than all others, it may be excluded with a justification for your exclusion (for example if enzyme rates generally range from 1 to 5 kpa/min, the removal of a data point at 20 kpa/min would be appropriate).
- List and describe safety precautions that must be taken during the lab, i.e. wear safety goggles throughout duration of experiment, avoid breathing vapors, etc.