MYP Laboratory Help
Research is what I'm doing when I don't know what I'm doing.
-Wernher von Braun
Section Links |
General HelpHow to write an MYP Lab ReportMYP Lab Report ChecklistMYP Science Lab Rubrics (B, C)Exemplars |
TEmplates:
Word Document: Here
Google Document: Here
VaRiables
Variable Definitions
- Independent Variable: The variable you are changing/ testing
- Dependent Variable: The data you are collecting (how will you measure if the IV is working )
- Control Variables: multiple aspects that must remain the same throughout all trials and all IV changes
- Control Group: Negative and Positive controls for IV, these make sure that when you test the IV you are actually testing the IV not some other unknown factor
Independent vs Dependent Variable
Choosing your Independent Variable
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Determining the Dependent Variable
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Control Variables vs Control Groups
Determining Control Variables
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Control Groups
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In your Lab report, Do NOT forget:
Consider using tables such as these below with your variables. Not required but useful.
- To identify each variable and explain it specifically
- To explain how you manipulate/ control each variable specifically – This includes specific numbers (ex. If I’m controlling temperature (at what temperature will you set it too?)
- To include Units AND Uncertainty* for anything measurable! Obviously if it isn't measureable it doesn't need uncertainty*
Consider using tables such as these below with your variables. Not required but useful.
How to write a Reserach Question
A good scientific research question contains the Independent and Dependent Variable as well as some important control variables.
It is possible to make a question too simple or too complicated.
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Examples:
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Background Reserach & Hypothesis
Background information should be relevant to the question and explain the relationship or possible expected relationships between the variables. Make sure to
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Your hypothesis can be one well-written sentence. It should sound something like “If...then...because...”.
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Procedure, Materials, and Safety
Your materials list should contain everything needed to carry out the experiment. Generally this should include all materials for all trials, but can include per trial materials. For each material listed:
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Safety/ Enviornmental/ Ethical:Generally most experiments have safety concerns. These can be a simple as using a knife to a large as dangerous chemicals and equipment being used. While it is less likely in Biology to deal with dangerous chemicals in high school lab, we are more likely to deal with ethical and environmental concerns.
ALWAYS State the concern and then describe how to reduce the issue.
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If you have ever tried to follow a recipe that did not make sense, you will recognize the frustration with writing them. Procedures must balance succinct writing with enough detail to be able to follow the instructions and recreate the lab.
- A numbered list is recommended (Although paragraph form is acceptable in some instances)
- Use command terms with direct instructions (Pour, measure, record, etc)
- Indicate what materials to use when.
- Always indicate how and when to change the independent variable
- State when & how to repeat trials
- ALWAYS, ALWAYS make sure you tell your readers when, where, and how to collect data (both qualitative and quantitative)
- Remember you are writing a recipe not a textbook.
Uncertainty
Measurement Uncertainty
Measurement Uncertainty is the uncertainty that comes with a data point and the instruments used to measure those points.
- Found by taking the smallest increment on a measurement and dividing by 2.
- Example graduated cylinder: each line increases by 1ml, so the smallest increment is 1ml. 1ml/2 =0.5ml. So the uncertainty is +/- 0.5ml
- Rulers are unique in that they actually have two lines of uncertainty. You make a judgement call at both the beginning of the ruler and the end of it.
- As a result the uncertainty is still divided by 2, but with the two lines added together it ends up being mulipled by (effectively canceling the division)
Note that the above examples of the beaker and graduated cylinder, the accuracy of the cylinder is much higher and less likely to cause problems. Always try to elimiate measurement uncertainty by using equipment with the lowest measurement uncertainty.
- This generally means DO NOT use beakers or erlyemeyer flasks to measure anything as they have much higher uncertainties than equipment like graduated cylinders, volumetric flasks and graduated pipettes.
- These uncertainty numbers should be recorded for any equipment or measurement that you have taken. Variables, Materials, Tables, and Graphs.
- Please note that you should NOT put the uncertainty with the numbers but in title headings.
STandard Deviation (STDEV)
Standard deviation is the measure of how far away a group of numbers is from the average.
For how to interpret error bars see "Analysis of data" section below
- Note that you MUST have an average to used STDEV.
- The greater the STDEV the more variation in your data trials and therefore more uncertainty.
- Variation is a good thing generally. As too perfect of numbers can cause doubt about the reliability of the data.
- Too much variation causes overlap with data points causing two points not to be statistically different and no difference in your data sets.
- Note that while STDEV may help you determine reliaibliy of your data points; it does not explain what caused the issues. That is something you must determine and explain in your evaluation.
For how to interpret error bars see "Analysis of data" section below
Tables & Data
Raw data are the numbers that you collect from your procedure AND the observations/ pictures you make along the way.
Below is an example of a data table. This table includes processed data and raw data, which is exceptable assuming it all fits in one table. If not, then you can make raw data tables and processed data tables separately.
- Qualitative data = observations
- Quantiative data= numerical data
- Any pictures must have labels with captions "Figure 1: color change after the reaction"
- Figures should always be referenced in the text of your lab. [This includes pictures used to explain the procedure.]
- Always make note of anything out of the ordinary or issues that occured, as these observations can be used to support your quantative data conclusions.
- Rule of thumb: Independent variable down the side, dependent variable across the top
- This can change dependending on how many variables and trials etc, but better to learn to rules before the exceptions!
- All units and uncertainties should be in column headings not with numbers!
- Title and label the table descriptively. Note that "raw data" is not a title.
- Example: Table 3: The change in mass of the orange after being in salt water for 24 hours.
Below is an example of a data table. This table includes processed data and raw data, which is exceptable assuming it all fits in one table. If not, then you can make raw data tables and processed data tables separately.
- You will also find some videos of how to do this using Word or Pages.
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Data Processing
Data processing is based on the type of data you have. This is often dependent upon your indepdent variable. At the MYP level, your dependent variables should always have a quantiative and qualitative aspect, you more than likely will not be dealing with anything classified as categorical. Some defintions:
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How do I know what kind of graph to Make?The type of graph is often dependent upon the independent variable. Generally:
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How to do Calculations and Graphs
Using Excel |
Using Numbers |
Data Analysis
Once you have data processed and graphed, from there you must analyze the data. This is can be done in a separate section of the report or in conjuction with the conclusion. Analysis means looking for:
So how do you analyze? |
Trendlines & R2 values
- On a scatter plot, create a best fit line/ trendline (a line that gives the general trend of the data)
- make sure your trendline actually fits the data. (ie: if it doesn't look linear don't use a linear line, you can change this usuing excel)
- With the best fit line, comes an R^2 value.
- R^2 is a measurement of how close your line fits your data
- The closer the number is to 1 the better the fit, and the more reliable the trends conclusion to your data.
- 0.7-1 = strong fit/ correlation
- 0.4-0.6= weaker fit/ correlation
- <0.3 = weak fit
- R^2 is a measurement of how close your line fits your data
Analyzing the above graph: we can see the high R^2 value (0.98) meaning that this trendline has a significant fit to the data. So we can be confident that the "negative linear relationship" trend is an accurate and reliable description of the relationship between the two variables. The low measurement uncertainty also adds reliability to the numbers. These would have been appropraite to use as error bars if desired instead of STDEV.
- Note that while stated in the analysis section, these should be discussed further in the evaluation section.
Error bars
Error bars on a graph offer a way to visually see whether two points on a graph are significantly different. While it is not as statistically reliable as running an actual statistics test (T-test or ANOVA) it does give you a better indication of the reliability of your data and can offer insight into why your trendline may not fit the data as well.
- You can use measurement uncertainty as error bars, and this is appropriate if you do not have averages or you do not have enough points to accurately calculate standard deviation.
- Standard deviation generally needs at least 5 points to be accurate, but you can use 3, as long as you have calculated and average.
Analyzing the above information: While the above graph has a very good trendline (R^2 of 0.98) the error indicated with the standard deviation demonstrates overlapping data points.
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Conlcusion
Your conclusion should connect the Data anaylsis with the research question, an answer to the hypothesis, AND the scientific context (ie the science of the lab) to each other.
- Explain the trends/ patterns you see in your graphs and tables (already idenfitied in analysis section)
- Answer your research question based on that description!
- Use your analysis to explain the relationship between the indepdent and dependent variables. Relate to the graph, trends, and analysis.
- Accept or Reject your hypothesis (use the data to support your answer)
- It is ok to reject your hypothesis as long as you can explain why
- Reference graphs and tables here that bring connection to why you are accepting or rejecting the experiment.
- Explain what you saw and learned with the science you are trying to investigate. (THE WHY OF THE EXPERIMENT- why did it do this!)
- Use outside references and your background information to explain why the graph and data appear to draw the relationship they do.
- If it did not do what your reserach said it should, explain what it should have done and what is wrong with it! Reference outside materials
Evaluation
Evaluations focus on whether or not your conclusion can be trusted. It has two sections: 1) Discussion of the strengths and weaknesses/errors of your lab with improvements 2) Extensions to the experiment.
STRENGTHS AND WEAKNESSES:
Based off of your analysis & observations, discuss
EXTENSIONS Extensions are things that you would continue to research next time based on what you have learned now. Note that these are NOT improvments, they are expansions of your current question and answer.
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Bibliography
Cite your Sources!!Cite your sources. In-text citations should be present in the background information, hypothesis, and conclusion. A complete bibliography should be provided at the end of the report. Purdue Online Writing Lab is a great place for information on formatting of sources.
APA citation of a website with author:
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What is Plagiarism?Plagiarism = using someone elses words or ideas without crediting the soure and passing them off as your own.
Plagiarism.org How do I know when and what to cite? - University of Arizona tutorial on Plagiarism |
Citation cites
While there are many fast sites that will make references for you, I'd recommend using Zotero.org. This allows you to create file folders for various projects and to connect directly to the web browsers.
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