Unit: Introduction to Chemistry The Scientific Method

The Scientific Method: An organized approach to solve problems. (We do this all the time!)

Steps in the Scientific Method: Observe Use your five senses Define the problem Hypotheses “Educated guess” Reasonable explanations for what was observed Observations often lead to questions, or problems. Ex: My flashlight won’t turn on. Question: “What is wrong with the flashlight?” Hypotheses is written as a plural because more than one explanation is needed. Ex: “The batteries must be dead.”

3. Experiments 4. Analysis 5. Conclusion (Theory) Tests each hypothesis in order to prove/disprove them 4. Analysis Compare the results from the experiment to the original hypothesis 5. Conclusion (Theory) A hypothesis supported by experimental evidence Experiments is a procedure that is used to test a hypothesis. Ex: Changing the batteries. The variable that is changing is often called the independent variable. The variable being tested is called the dependent variable. If the flashlight did not turn on by changing the batteries, other experiments to test the rest of the hypotheses are used. Ex: Changing the light bulb. Analysis and Experiments steps are usually performed together. Theories are made when a hypothesis agrees with the results of the experiments repeatedly. Theories are often modified.

Law: Used to describe a natural phenomenon which has been tested over a long period of time under different conditions. Laws do not try to explain why something is occurring. Instead, theories are used for that purpose. Laws are simple concise statements such as “What goes up, must come down.” Or Newton’s Laws of motion.