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

Scientific Method Scientific Method- an organized and logical approach to solving a problem.

Scientific Method Observations- a sight, sound taste or smell that is recordable. Inference- uses observations to conclude something about a situation.

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

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

Scientific Method Hypothesis- a testable and measurable prediction of what will occur in the experiment. Experiment- An organized method for testing a hypothesis and collecting data.

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. Example- If water daphnia are exposed to mountain dew, then the heart rate of the daphnia will increase.

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.

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

Designing Controlled Experiments Experiments must test only ONE variable. Examples: time, amount of sunlight, amount of food, water, etc. Controlled variables or constants stay the same.

Designing Controlled Experiments Identify the independent variable, dependent variable and constants in the experiment below. Write a possible hypothesis for this experiment.

Experiments Experiment is divided into two groups Control group- Exposed to the same conditions (constants) as experimental group but does not receive the Independent variable. The control group serves as the comparison. Experimental group- Receives the Independent variable. The experimental group shows the effect of the variable that is being tested.

Experiments Identify the following: IV: E. Group: C. Group: Example: In testing a new weight loss drug, one group is given the medicine but the other is given a placebo or fake drug. Identify the following: IV: E. Group: C. Group:

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.

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.) Specific data to support/reject the hypothesis 4.) Errors that occurred 5.) What you learned in the lab

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

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:

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-