Chapter 1 Chemistry in our Lives 1.2 Scientific Method: Thinking Like a Scientist Learning Goal Describe the activities that are a part of the scientific method. Linus Pauling won the Nobel Prize in chemistry in 1954. © 2014 Pearson Education, Inc.

Chapter 1 Readiness Scientific Method The scientific method is a set of general principles that helps to describe how scientists think. Students make observations in the chemistry laboratory. © 2014 Pearson Education, Inc.

The Scientific Method Involves observations, facts obtained by observing and measuring events in nature. an hypothesis, statement that explains the observations. experiments, procedures that test the hypothesis. a theory, model that describes how observations occur using experimental results.

Summary of the Scientific Method

Everyday Scientific Thinking Observation: Yesterday you went to visit your friend. Soon after you arrived, your eyes began to itch and you started to sneeze. You observed that your friend has a new cat.

Everyday Scientific Thinking Hypothesis 1: Perhaps you are allergic to cats. Experiment 1: To test your hypothesis, you leave your friend’s home. If the itching and sneezing stop, perhaps your hypothesis is correct. If the itching and sneezing do not stop, perhaps you have a cold.

Everyday Scientific Thinking Observation: Upon leaving your friend’s home, the itching and sneezing stop. The observation supports your original hypothesis. To confirm, you visit another friend with a cat.

Everyday Scientific Thinking Experiment 2: Visiting a second friend with a cat causes your eyes to itch and you begin to sneeze again, further supporting your hypothesis. Theory: The experimental results indicate that indeed you are allergic to cats.

Learning Check The step in the scientific method that is indicated in each of the following examples is: (1) observation (3) experiment hypothesis (4) theory A blender does not work when plugged in. The blender motor is broken. The plug has malfunctioned. The blender does not work when plugged into a different outlet. The blender needs repair.

Solution The step in the scientific method that is indicated in each of the following examples is: (1) observation (3) experiment hypothesis (4) theory (1) A blender does not work when plugged in. (2) The blender motor is broken. (2) The plug has malfunctioned. (3) The blender does not work when plugged into a different outlet. (4) The blender needs repair.

Chemistry Link to the Environment In the 1950’s problems attributed to DDT began to surface when insects became more resistant to DDT. Although low concentrations were used on crops, DDT made its way to the ocean and was absorbed by fish.

Chemistry Link to the Environment Birds feeding on fish, such as the Brown Pelican, began to have lower calcium levels in their eggs, and their young began to die. In 1972, DDT was banned in favor of pesticides that broke down faster in the environment.