1. Analyze the components of a properly designed scientific investigation

2. Evaluate the accuracy and precision of data

Chemistry is a branch of physical science that studies the composition, structure, properties and change of matter.

The Scientific Method Definition: • A logical, stepwise approach used by scientists to find answers to questions.

Steps:

1. Observation: Observations are made by scientists about their surrounding environment. The observations enable the scientists to illicit questions.

2. State the Problem: The problem statement is in the form of a question. It is derived from the observations made by the scientist. It must be measureable.

4. Form a Hypothesis: A hypothesis (an educated guess) is formed and stated based upon the background information acquired by the scientist. Example – If I give my plants fertilizer in the spring, they will have more flowers.

3. Conduct Background Research: Information about the problem must be researched by the scientist. This is accomplished by research journals and periodicals, textbooks, internet databases, consultation with professors, etc.

The Acme Cleansers Company wants to do some advertising for its new anti-bacterial kitchen cleaner. The advertising executives want to run some tests that show that their new product is better than the current best-selling brand of kitchen cleaner.

Mrs. Averett’s Advanced Topics class is in charge of filling the bird feeders at Central Park. You notice that the nuthatches seem to prefer to eat at the sunflower seed feeder more than they eat at the mixed seed feeder.

5. Design and Perform an Experiment: It is essential for the scientist to gather a list of materials and methods before the experimentation begins. In addition, it is essential that the experimenter designs the experiment in such a way that it is reproducible. A proper experiment compares two or more things but changes only one variable or factor in the experiment.• Many experiments will have two groups

• Experimental group – The group in an experiment that receives the variable being tested.

• The control group – The group that does not receive the test variable

• Types of variables

• Independent variable – The variable that is purposely changed

• Dependent variable – The variable that is measured

• Controlled variable – The variable that remains constant

What is the independent variable?A. Gas mileage of carsB. Type of carC. Type of asphalt

What is the independent variable?A. Amount of money earnedB. Money spent of eating outC. Type of restaurant

What is the dependent variable?A. Type of band-aidB. Covering a scrapeC. Healing time

What is the control group?A. Athletes who do not get enough

sleepB. Athletes who get a good night’s restC. The type of race

What is the experimental group?A. The 3N Chemical CompanyB. The wood treated with the new termite

preventionC. The wood treated with the leading brand of

termite prevention

Identify theIndependent variableDependent variableExperimental groupControl group

6. Gather, Organize, and Analyze Data: Data (information from the experiment) whether qualitative or quantitative must be accurately recorded. The data can be properly displayed in a graph, chart, table, etc. Data should be accurate and precise.

Accuracy: How close you are to the

actual value Depends on the person

measuring

Precision: How finely tuned

your measurements are or how close they can be to each other

Depends on the measuring tool

Accuracy & Precision may be demonstrated by shooting at a target.

Accuracy is represented by hitting the bulls eye (the accepted value)

Precision is represented by a tight grouping of shots (they are finely tuned)

Accurate & Precise

Precise but not accurate Not precise or accurate

Accurate but not Precise

Susan conducts an experiment five times and gets a solution concentration of 1.9M, 2.1M, 1.8M, 1.9M, and 2.2M. The known concentration of the solution is 2.0M. Which of the following is true about Susan’s results?

A. They are accurate, but not preciseB. They are precise, but not accurateC. They are neither accurate nor preciseD. They are both accurate and precise

Martin is conducting an experiment. His first test gives him a yield of 5.2 grams. His second test gives him a yield of 1.3 grams. His third test gives him a yield of 8.5 grams. On average, his yield is 5.0 grams, which is close to the known yield of 5.1 grams of substance. Which of the following are true?

A. They are accurate, but not preciseB. They are precise, but not accurateC. They are neither accurate nor preciseD. They are both accurate and precise

Jared is practicing for a golf tournament. His normal driver distance is 250 yards. He hits three balls with his driver, and they travel a distance of 190 yards, 195 yards, and 193 yards. Which of the following is true?

A. They are accurate, but not preciseB. They are precise, but not accurateC. They are neither accurate nor preciseD. They are both accurate and precise

7. Form a Conclusion: Based upon the experimental results, conclusions can be made regarding the study. These conclusions should support or reject the hypothesis but never prove or disprove.

How are these concepts related to each other?

HYPOTHESIS

THEORY

L A W (fact)

When proven that it always works

When supported over time