Chemistry and the Scientific Method Chapter 1

Chemistry Why is it important to learn chemistry? It’s important to learn chemistry… To become a scientist. For careers: Medical, forensics, environmental, agricultural, engineering… To make decisions about technology and the environment. Understand important issues

What is chemistry? What are three things you think of when you hear the word chemistry?

What is chemistry? Why do leaves turn colors in fall? Why does iron rust? What makes fireworks change colors? What happens inside a battery?

World Issues *In groups, list main problems in the world (hunger, disease, etc.). Then write on the board and circle which ones have to do with chemistry.

The Scientific Method. Observation – Recognize a problem or notice something happening. Example: You saw Mr. X outside KFC on Monday. Hypothesis – Propose a solution or explanation. Example: Mr. X eats at KFC on Mondays.  

Experiment – Test your hypothesis to see if it is true Experiment – Test your hypothesis to see if it is true. This leads to a new observation! You can accept or reject your hypothesis. If you reject your hypothesis, you can revise it and test it again. If you accept your hypothesis, you do more experiments to build up more evidence for your hypothesis.

Experiment (Continued) Example: How can you test the hypothesis that Mr. X eats at KFC on Mondays? What data would support your hypothesis? What data would lead you to reject your hypothesis?

The Scientific Method. After the process is repeated, you can collect the hypotheses into a theory. A scientific theory explains the behavior of nature. A theory answers the question “why?” A natural law summarizes behavior, but does not explain why it happens. A theory does not become a law.

The Scientific Method Every day you bring a delicious chocolate bar to school. One day, it is gone when you want to eat it at lunch. The next day, the same thing happens. Make a hypothesis about what happened to the chocolate and design an experiment to test the hypothesis.

If something is scientifically proven, it doesn’t mean it’s true If something is scientifically proven, it doesn’t mean it’s true. Scientific theories can be proven to be incorrect. Example: When scientists were studying the structure of DNA, Linus Pauling proposed that DNA had a triple helix. Later, Watson and Crick showed that it was a double helix. 

Scientific explanations must meet certain criteria: they should be logical, respect the rules of evidence, be open to criticism, report methods and procedures, and make knowledge public.

Before a research report is published in a scientific journal, it must be peer-reviewed. This means that other scientists in the same field must read and approve of the report.

The Scientific Method Classify the following as an observation, theory or law. Mr. Bly eats an egg and vegetable sandwich every day. Mr. Bly eats sandwiches because they are very delicious. I saw Mr. Bly eating a sandwich yesterday at 5 pm.