Pre-class Activity 9/11 Chemistry is the study of matter and the changes that it undergoes. What is matter? Be prepared to give two examples of matter that can be found in the classroom

Chemistry and Matter Chemistry is the study of matter and the changes that it undergoes. Anything that has mass and takes up space A measurement that reflects the amount of matter

Questions What in the universe isn’t matter? Energy Why aren’t the terms mass and weight interchangeable? Weight is not only a measure of the amount of matter, but also a measure of the effect that gravity has on matter

Scientific Method – A Systematic Approach OBSERVATIONHYPOTHESISEXPERIMENTTHEORY Draw conclusions and revise hypothesis Theories are supported by many experiments SCIENTIFIC LAW

Theory vs. Law Arise following many, many experiments Provides an explanation of what occurs in nature Merely states what occurs in nature

Observations Hot 300 o Qualitative vs. Quantitative Temperature Height Mass Length

Pre-class Activity 9/14 A scientist owns fish that are very sensitive to changes in temperature. One morning, after a huge storm, he came into the lab only to find that all the fish in his tank were dead. He suspected that there might have been a power outage due to the storm, in which the power to the heater may have been interrupted. To test this, he measured the temperature of the tank, only to find that it is normal. Identify the observation, hypothesis and experiment in the paragraph above. Does the result of the experiment support the hypothesis? Homework: Read The Milk Lab, continue with HW assignments 1,2,3. Homework Assessment #1 – Thursday 9/17, Element Quiz – Friday 9/18

Experiments A set of controlled observations that test a hypothesis. Key Terms Variable: A quantity or condition that can have more than one value Independent Variable: A variable that is changed by the investigator in an experiment Dependent Variable: A variable the changes in response to the independent variable Control: A standard for comparison

Experimental Design Example The Effect of Temperature on the Respiration Rate of Fish Temp ( o C) Respiration Rate What is the dependent variable? What is the independent variable? What would be an appropriate control? What is the relationship between respiration rate and Temperature?

Pure vs. Applied Research Gaining knowledge for the sake of knowledge Vs. Gaining knowledge to solve a specific problem

Mrs. Pav’s Milk Lab Write-Up Pupose: To determine if milk type affects the migration time of food coloring in the milk experiment Hypothesis: If whole milk is substituted for skim milk in the milk experiment, the food coloring will migrate slower. Materials: In addition to materials listed for the milk lab, whole milk was added Procedure: Refer to written procedure for the milk lab. The migration time of food coloring was measured by using a stop watch to record the time that it took for the food coloring to migrate to the edge of the petri dish. Results: The time for the control (skim milk) was 4.8 seconds.The time for the experimental group (whole milk) was 3.2 seconds. Conclusions: The hypothesis was confirmed by the data because the migration time of food coloring increased for whole milk as compared to skim milk