Agenda- 9.3.2014

1. Agenda- 9.3.2014 1.) D.Q.Q 2.) Index Card Challenge 3.) Finish Safety Contracts 4.) Safety Challenge 5.) Set-up binders 6.) Scientific Method Review HOMEWORK: Signed safety contracts and syllabus due Friday.

2. What is Chemistry? Chemistry- the study of matter and the changes matter undergoes. Matter- Anything that has mass and takes up space.

3. Scientific Method Scientific Method- an organized and logical approach to solving a problem. Observations- a sight, sound taste or smell that is recordable. Inference- uses observations to conclude something about a situation. Hypothesis- a testable and measurable prediction of what will occur in the experiment. Experiment- An organized method for testing a hypothesis and collecting data.

4. Logic and Reasoning Logic- Common sense. Using basic background information to make decisions and choose next steps. Reasoning- Using common sense to evaluate a situation and explain what you are observing based on the data you collect.

5. Observations vs. Inference Observation: Your car will not start. Use what you know about cars to come up with ideas (inferences) to test. Inference=

6. Observation vs. Inference Observation: Mr. Shultz comes in the room and asks to speak with a student. Inference: Observation: Inference: It is about to rain.

7. Writing a Hypothesis Must begin with “If” and have “then” in the middle. Cannot have pronouns such as I, me, we, us, them, they, our. Must have a measurable outcome.

8. Designing Controlled Experiments • Experiments must test only ONE variable. • Examples: time, amount of sunlight, amount of food, water, etc. • The variable that is changed (manipulated) is the independent variable. • The variable that is observed and that changes in response to the independent variable is the dependent variable (responding variable).

9. Experiments • Experiment is divided into two groups • Control group- Exposed to the same conditions as experimental group but does not receive the Independent variable. • Experimental group- Receives the Independent variable. Example: In testing a new drug, one group is given the medicine but the other is given a placebo or fake drug.

10. Data • Collect detailed records of experimental observations • Two types: • Qualitative- descriptive and involve characteristics that cannot be counted. • Quantitative- numerical representation of the results obtained through counting or measuring.

11. Conclusion • An evaluation of the data, observations and inferences to determine if the hypothesis is correct or incorrect. • A conclusion must state: • 1.) Original hypothesis • 2.) Whether the hypothesis was or was not supported by the data • 3.) Data to support/reject the hypothesis • 4.) Errors that occurred • 5.) What you learned in the lab

12. Sources of Error • Mistakes that can occur in a lab • Mis-measuring • Spills • Did not follow directions • In medical studies, both experimental and control groups should be quite large. Why do you think that is?

13. Applying the Scientific Method • Researchers are studying the effects of chemical dioxins in killing cockroaches. The 100 cockroaches in Group A are sprayed with the chemical dioxins while the 100 cockroaches in Group B are not sprayed with the chemical dioxins. After 3 hours, 45/100 of Group A cockroaches are dead and only 1 of the cockroaches from Group B is dead. • Experimental Group: • Control Group:

14. Applying the Scientific Method A group of people take a diet pill.  After 3 months, they measure the amount of weight they lost. Independent Variable: Dependent Variable:

15. Dirty Car vs Clean Car • While we watch the video clip, please identify the following: • Hypothesis- • Independent Variable- • Dependent Variable- • Experimental Group- • Control Group- • Controlled Variables-