Read the following conclusion and reason that a student named Nguyen wrote. It is about the experiment to determine the relationship between magnet size and strength for magnets made of the same material. (You can assume the experiment was a fair test.) |
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Nguyen Conclusion – I conclude that when the magnet size increases, its strength increases. Reason – For the three magnets used in our experiment, as the size of the magnets increased from small to medium to large, the class’s strength rankings of the magnets increased from weakest to middle to strongest. |
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Is this conclusion valid or not valid? Isabel used How To Evaluate an Experiment Conclusion to help decide. She assumed that the experiment was a fair test because she was told that it was. Then she determined that Nguyen supported his conclusion with a good reason because it was based on evidence and used all the class data. Therefore, Isabel decided that Nguyen’s conclusion was valid. |
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Look at How To Evaluate an Experiment Conclusion, located in the Appendix. This lists all the criteria that you use to decide whether a conclusion is valid or not valid. 
Your teacher will review the criteria with you and will go over your decisions about why the students’ reasons are poor.
