Scientific Reasoning Forensic Science

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Copyright © Texas Education Agency All rights reserved. Images and other multimedia content used with permission. The Cycle of Science Scientific reasoning must use both inductive and deductive reasoning 3

Copyright © Texas Education Agency All rights reserved. Images and other multimedia content used with permission. The Cycle of Science (continued) Inductive reasoning – moving from specific observations to broader generalizations and theories – Begin with specific observations and measurements; then detect patterns and regularities – Formulate some tentative hypothesis that we can explore – Finally develop some general conclusions or theories 4

Copyright © Texas Education Agency All rights reserved. Images and other multimedia content used with permission. The Cycle of Science (continued) Deductive reasoning – works from general to specific – Begin with creating a theory about a topic of interest – Narrow that down into a more specific hypothesis that we can test – Narrow that down even further when we collect observations to address the hypothesis – Test the hypothesis with specific data 5

Copyright © Texas Education Agency All rights reserved. Images and other multimedia content used with permission. How Scientists Reason Scientists use analogies to form theories, generate hypotheses, and comprehend patterns of data Scientists use the scientific method to generate these and create experiments to test their hypotheses 6

Copyright © Texas Education Agency All rights reserved. Images and other multimedia content used with permission. Experimental Control Scientists work to create experimental control It is important for comparison, so scientists know what has the effect in the experiment The control is the normal condition(s) for the subject being tested 7

Copyright © Texas Education Agency All rights reserved. Images and other multimedia content used with permission. Variable The variable is the thing that is being changed in the experiment You should only have one variable 8

Copyright © Texas Education Agency All rights reserved. Images and other multimedia content used with permission. Observation Observations are recorded facts about what you see There are two types of observations – Quantitative – results in a numerical form, with a unit – Qualitative – results in a descriptive form 9

Copyright © Texas Education Agency All rights reserved. Images and other multimedia content used with permission. Conclusions Scientists make conclusions based on the data collected and the observations made Sometimes the conclusions prove the hypothesis and sometimes they disprove the hypothesis 10

Copyright © Texas Education Agency All rights reserved. Images and other multimedia content used with permission. Resources Davis, Raymond. Modern Chemistry. Holt McDougal; 1 st Edition, 2002 Francisco Redi Experiment Do an Internet search for the following: – Will Brain-Scanning Lie Detectors Free the Innocent or Jail Them – Burgled Bonuses 11