1. Unit 1: Introduction to Chemistry

2. The Scientific Method: An organized approach to solve problems. (We do this all the time!)

3. Steps in the Scientific Method: 1.Observe Use your five senses Define the problem 2.Hypotheses “Educated guess” Reasonable explanations for what was observed

4. 3. Experiments Tests each hypothesis in order to prove/disprove them 4. Analysis Compares the results from the experiment to the original hypothesis 5. Conclusion (Theory) A hypothesis supported by experimental evidence

5. Law: Used to describe a natural phenomenon which has been tested over a long period of time under different conditions.

6. You’re not going to expect this... Let’s try something to practice the scientific method.

7. Coke vs. Diet Coke Demonstration (1) Observation:Coke sank, Diet Coke floats Observations Coke Observations Diet Coke (2) Hypotheses In a colorless liquid Not the same liquids Has caffeineNo caffeineCaffeine more dense Red canGold canWeight of cans are different Contains sugarContains nutra- sweet Sugar is more dense than nutra-sweet Less carbonatedMore carbonatedMore CO 2 makes the can float

8. Coke vs. Diet Coke Demonstration (1) Observation:Coke sank, Diet Coke floats (2) Hypotheses(3) Experiments and (4) Analysis Maybe not the same liquids Switch the cans to see if the same observation occurs Caffeine more denseReplace the caffeine-free diet coke with a diet that contains caffeine Different color of cans (weigh different) Weigh the cans on a balance Sugar is more dense than nutra-sweet Weigh out the sugar, weigh out the nutra-sweet More CO 2 makes the can float Collect the gas from each can

9. Coke vs. Diet Coke Demonstration (1) Observation:Coke sank, Diet Coke floats (2) Hypotheses(3) Experiments and (4) Analysis Maybe not the same liquids Switch the cans to see if the same observation occurs Caffeine more denseReplace the caffeine-free diet coke with a diet that contains caffeine Different color of cans (weigh different) Weigh the cans on a balance Sugar is more dense than nutra-sweet Weigh out the sugar, weigh out the nutra-sweet More CO 2 makes the can float Collect the gas from each can (5) Theory: Since 39g of sugar is in regular Coke versus 188mg nutra-sweet in Diet Coke, the regular Coke is more dense, and therefore sinks.