chapter 1 lecture basic chemistry fourth edition chapter 1 chemistry in our lives 1.2 scientific...
TRANSCRIPT
Chapter 1 Lecture
Basic ChemistryFourth Edition
Chapter 1 Chemistry in our Lives1.2 Scientific Method: Thinking Like a Scientist
Learning Goal Describe the activities that are a part of the scientific method.
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Linus Pauling won the Nobel
Prize in chemistry in 1954.
Scientific Method
The scientific method is a set of general principles that helps to describe how scientists think.
Chapter 1 Readiness
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Students make observations
in the chemistry laboratory.
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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.
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Summary of the Scientific Method
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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.
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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.
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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.
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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.
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Learning Check
The step in the scientific method that is indicated in each of the following examples is: (1) observation(3) experiment(2)hypothesis (4) theory
A.A blender does not work when plugged in.B.The blender motor is broken.C.The plug has malfunctioned.D.The blender does not work when plugged into a different outlet.E.The blender needs repair.
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Solution
The step in the scientific method that is indicated in each of the following examples is: (1) observation(3) experiment(2)hypothesis (4) theory
A.(1) A blender does not work when plugged in.B.(2) The blender motor is broken.C.(2) The plug has malfunctioned.D.(3) The blender does not work when plugged
into a different outlet.E. (4) The blender needs repair.
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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.
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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.