Chapter 1: Chemistry & You

Criteria of Science Consistent Observable Natural Predictable Testable Tentative

Is it Science? Non-science – movie ratings, food preferences Pseudoscience – phrenology, homeopathy Emerging science – nanochemistry

Chemistry The study of chemistry investigates all substances and the changes they can go through. submicroscopic level

Chemistry Has its roots in the pseudoscience of Alchemy Separated mixtures and purified chemicals Lavoisier and Boyle helped change alchemy into a real science by introducing structure and experimentation.

The Scientific Method Begins Curiosity Observation, question, or problem “Hmmmmmm” Let me think about that.

Hypothesis Scientific Hypothesis: A testable statement about the natural world e.g. Bubbles will last longer in cold temperatures than in warm. A hypothesis must be testable, and be able to be potentially proven right or wrong.

Scientific Method Cont. Experimental Procedures – Steps to test our hypothesis. Results and Analyze your results. Conclusion - Revise your hypothesis and start over again.

Control & Variables Variable - what you are testing Independent Variable – changed by the experimenter. Dependant Variable –changes in response to the Independent Variable. Control - standard for comparison.

Scientific Method After results are reproducible, scientific studies are published in journals. Scientists review and critique published work. Science is self correcting and tentative.

Scientific Theories and Laws Theory – well tested explanation that unifies a broad range of observations and scientific results. (atomic theory, cell theory) Strong predictive abilities (Plate tectonics). Scientific Law: Concise statement that summarizes the results of many observations e.g., Dalton’s Law, Laws of Thermodynamics, Law of Conservation

The Scientific Method The steps in the scientific method do not have to occur in the order shown. Comparing and Contrasting How are a hypothesis and a theory similar? How are they different? Remember that it is crucial for the data to be analyzed and then adjust your theory accordingly.

Experimentation Remember that after experimentation, the data must be analyzed. At this point, one of three things can happen. The hypothesis or theory can be tossed out. The theory has to be adjusted. The data gives enough information where predictions can be made and we have a LAW.