2.1 Practical Investigation
Carry out a practical physics investigation that leads to a non-linear mathematical relationship.
practical_investigation_2-1_specifications.pdf | |
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how_to_write_a_lab_report.pdf | |
File Size: | 331 kb |
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sample_acceleration_report.pdf | |
File Size: | 353 kb |
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Assessment Information:
You will carry out an independent experiment during one class period. You will then have at least two days out of class to process your data and write a scientific report. Reports must by typed, including all tables and graphs (except the raw data).
Your teacher will initial your raw data collection sheet to verify that you have collected your own data. This sheet must be turned in with your final report.
You will carry out an independent experiment during one class period. You will then have at least two days out of class to process your data and write a scientific report. Reports must by typed, including all tables and graphs (except the raw data).
Your teacher will initial your raw data collection sheet to verify that you have collected your own data. This sheet must be turned in with your final report.
2.1.1 Experimental Variables
Lesson Overview
When conducting a science experiment, it is important to be able to identify the key variables. Dependent Variable is the one that you measure. Independent Variable is the one that you change (to see how it effects the dependent variable). Control Variables are things that could have an impact on the experiment they were not kept constant. You should be able to:
- Identify the dependent and independent variables for given experiments and justify your choice. - Determine possible control variables and explain why they might need to be controlled. - Write an Experimental Aim (purpose statement) that includes reference to the independent and dependent variables. Homework (to be started in class):
Pages 9-11 all Q's |
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2.1.2 Data Collection: Upper and Lower Limits
Lesson Overview
It is important to collect data over a wide enough range to show an accurate representation of the data trend. It is, however, impractical to collect data over an infinite range. It is important to justify why the upper and lower limits of your data collection were chosen. You should be able to:
- Determine what the upper and lower limits of a given experiment with justification. - Determine what data points should be collected in between the upper and lower limits in order to see an accurate trend. Homework (to be started in class):
Pages 14-15 all Q's Pages 12-13 *special instructions* For each scenario on pages 12-13, Explain: * How you would find the range * What the range might be * How many samples you would take |
EXAM NOTE:
Five data points will be the minimum required to pass. It is recommended that you have more. You will need to determine you own range but make sure it is wide enough in order to get full marks. This will likely encompass the entire workable range of the experiment. Remember that "0" can also be a data point. |
2.1.3 Accuracy Improving Techniques
Lesson Overview
Every measurement has an inherent amount of error. As scientists, we want to avoid and account for as much error as possible. How you use equipment and take measurements will help account for systematic error. Random error is primarily accounted for by taking multiple samples (running multiple tests) and averaging the results. For some experiments (ie pendulum) it may also be necessary to take readings over a longer period of time and then average to find a single test result. You should be able to:
- Identify various types of systematic error and minimize it's effect through proper technique. - Minimize random error (but not systematic error) by taking lots of measurements and averaging the result. NOTE Common Student Mistake: This is different from identifying control variables. Do not confuse "accuracy improving techniques" with "controlling key variables". Homework (to be started in class):
Pages 16-21 |
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2.1.4 Recording and Analyzing Data
Lesson Overview
All Data (including raw data) should be collected in an organized, properly labeled data table, including units. Processed data needs to be recorded in appropriate SI units. If there are any data points that stand out as outliers, these should be noted and omitted from averages. Once the data is plotted, a curve or line of best fit should be drawn through the data to emphasize the general trend. You should be able to:
- Record data in an appropriately constructed table - Recognize and acknowledge outliers - Plot your data on an appropriately constructed graph - Draw a curve or line of best fit |
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Homework (to be started in class):
Page 24 - Recording Data Page 22 - Outliers Page 25 - Line of Best Fit Page 26 - Graphing |
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Bonus: Graphing Skills
Notes on graphs:
- Title that relates the dependent and independent variables - Properly labeled axis with appropriate SI units - Scale should be selected so that data fills most of the graph - Scale values for each axis should be shown at regular intervals (not pictured below) - Large enough to see what is going on (at least 1/2 page, may be full page) - For the transformed linear graph, remember to transform the title of the axis AND the units.
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2.1.5 Writing a Scientific Report
Lesson Overview
A scientific report should be well organized, include all the important information, without adding extra fluff. This is also where your data needs to be analyzed and discussed in mathematical/scientific terms.
There are many different ways to write a scientific report. To keep things simple, please use the general format:
- Aim
- Method
- Results
- Conclusion
- Discussion
A scientific report should be well organized, include all the important information, without adding extra fluff. This is also where your data needs to be analyzed and discussed in mathematical/scientific terms.
There are many different ways to write a scientific report. To keep things simple, please use the general format:
- Aim
- Method
- Results
- Conclusion
- Discussion
You should be able to:
- Organize your report into: Aim, Method, Results, Conclusion, Discussion and know what belongs in each section
- Calculate a gradient for a line of best fit
- Use the gradient to write a full equation
- Write a conclusion that includes a proportionality statement and the full equation
- Write a discussion about your experiment
The following PDF document may be useful in writing various parts of your report.
- Organize your report into: Aim, Method, Results, Conclusion, Discussion and know what belongs in each section
- Calculate a gradient for a line of best fit
- Use the gradient to write a full equation
- Write a conclusion that includes a proportionality statement and the full equation
- Write a discussion about your experiment
The following PDF document may be useful in writing various parts of your report.
how_to_write_a_scientific_report.pdf | |
File Size: | 793 kb |
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Homework (to be started in class):
Page 23 - Writing a Method
Page 30 - Calculating a Gradient
Page 34 - Writing a Full Equation
Page 37 - Conclusion and Discussion
Page 23 - Writing a Method
Page 30 - Calculating a Gradient
Page 34 - Writing a Full Equation
Page 37 - Conclusion and Discussion
2.1.6 Non-Linear Relationships
Lesson Overview
Once you have graphed your processed data, you should see a non-linear relationship. You then need to transform the data for one of your variables (usually the independent) and plot a new linear graph of your transformed data. Once you have a linear graph, you can find the gradient.
The types of non linear relationships will be limited to: squared, square root, inverse, inverse squared.
COMMON STUDENT MISTAKE:
-Math terms that describe the shape of a graph (parabolic, exponential, hyperbolic, etc), without describing the exact relationship, are NOT acceptable. Example: "The non linear graph suggests a squared relationship"
-This should be a PROPORTIONAL statement, not an equation. Example: "Transforming the data shows that y is proportional to x squared" or "y α x^2"
Once you have graphed your processed data, you should see a non-linear relationship. You then need to transform the data for one of your variables (usually the independent) and plot a new linear graph of your transformed data. Once you have a linear graph, you can find the gradient.
The types of non linear relationships will be limited to: squared, square root, inverse, inverse squared.
COMMON STUDENT MISTAKE:
-Math terms that describe the shape of a graph (parabolic, exponential, hyperbolic, etc), without describing the exact relationship, are NOT acceptable. Example: "The non linear graph suggests a squared relationship"
-This should be a PROPORTIONAL statement, not an equation. Example: "Transforming the data shows that y is proportional to x squared" or "y α x^2"
The slide show goes through several examples of transforming non linear graphs, finding the slope, and writing an equation.
Homework (to be started in class): Pages 27-36 |
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Practical Investigations
Linear Relationship: Hookes Law Experiment
Hookes Law Experiment performed in class.
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Squared Relationship: Free Fall Investigation
Here is an examplar of an excellence level report. Note that it is not perfect as there are a few missing elements, but it is still a good example.
sample_acceleration_report.docx | |
File Size: | 91 kb |
File Type: | docx |
Square Root Relationship: Simple Harmonic Motion
Pendulums and springs both follow the same principles of Simple Harmonic Motion. During the Pendulum experiment we will be experimentally finding the value for gravity.
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Extra: Calculating Pi
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