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Intro to Chemistry. What is Chemistry?. Chemistry is the study of matter and the changes it undergoes. What is matter?. Matter is anything that has mass and takes up space. Mass vs. Weight. Mass Reflects the amount of matter in an object
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What is Chemistry? • Chemistry is the study of matter and the changes it undergoes.
What is matter? • Matter is anything that has mass and takes up space.
Mass vs. Weight • Mass • Reflects the amount of matter in an object • Constant and does not change regardless of location • Weight • Reflects the amount of matter in an object • Changes depending on the gravitational pull
Scientific Method • Systematic approach used to solve a problem • The main steps: • Observations • Hypothesis • Experiments • Data/Results • Analysis • Conclusions
Observation vs. Inferences • Observation • The act of gathering information based on your senses • Inference • A reasonable conclusion based on an observation and prior knowledge • Warm Up Demo
Activity think-pair-share • Separate the following into twogroups and create a name for each of the groups: • Rotten odor • 12.4 feet • Boiling point of 85°C • Appears cloudy • Purple • 5 leaves • 3.70 seconds • square
Types of Observations —describes physical characteristics • Color, odor, shape —numerical information • How much, how little, how big, how fast Qualitative data Quantitative data
Testing Hypotheses • Hypothesis—a proposed explanation for an observation • Experiment—a method to test a hypothesis • Variables • Independent—manipulated variable; the variable that you change during the experiment
Dependent—responding variable; the variable that is measured during the experiment • Control—the standard for comparison Dependent Responding Y-axis Manipulated Independent X-axis “DRY MIX”
Hydrangeas Lower the pH by adding aluminum to the soil Raise the pH by adding phosphorus in the soil water
Data/Results • Collecting qualitative/quantitative data • Making graphs, tables, charts
Analysis • Describing patterns and trends using your data • Calculate degree of uncertainty
Conclusion • Accept or reject hypothesis • Identify sources of error • Suggestions for further experimentation
Theory vs. Law • Scientific Theory • the “why” • An explanation that has been supported by many experiments, based on data • Scientific Law • the “what” • Concise statement that describes and summarizes events of many experiments and observations