The Scientific Method Ch. 5

Forming a Hypothesis Hypothesis = testable predictions that explain certain observations. Hypothesis = testable predictions that explain certain observations.  Hypothesis is an educated guess, together with observation, forming a hypothesis is the first step in the scientific method.  Stating and writing your hypothesis gives you a goal and a focus.

Reasoning Skills Inductive and Deductive Inductive reasoning = drawing a general conclusion from specific facts or experiences. Inductive reasoning = drawing a general conclusion from specific facts or experiences.  Ex. if you wrapped muffins and a sandwich, which becomes dry by lunchtime, you might conclude that the plastic wrap is faulty. Deductive reasoning = You reach a conclusion about a specific case based on known facts and general principles. Deductive reasoning = You reach a conclusion about a specific case based on known facts and general principles.  Such reasoning is often expressed as “if….then” statements  “If water expands when it freezes and my soft drink is mostly water, then the can could explode in the freezer”

Experimentation Experiments = A way to test a hypothesis in order to verify or disprove it. EEEExperiment includes a list of equipment and materials, as well as a procedure that gives step- by-step instructions CCCCarry out experiments in a logical, organized manner BBBBecause foods are not uniform in composition, your results may vary from those of your classmates YYYYour observation may also lead you to form a new hypotheses that will need to be tested by performing additional experiments

Controlling Variables Variables = factors that can change in an experiment. Variables = factors that can change in an experiment.  By controlling all the variables except one, you get more reliable results.  Ex. If you wanted to determine whether glass, plastic or metal bowls are best for whipping cream, what variables could affect the outcome?  Bowl sizes and shapes; temperature of the whipping cream samples; types of beating device; the whipping speed are just a few examples. Independent variable = this is a factor that you change. Ex. would be the bowl material Independent variable = this is a factor that you change. Ex. would be the bowl material Dependent variable = is a factor that changes as a result of the independent variable Dependent variable = is a factor that changes as a result of the independent variable

Analyzing Data Data = is the information gathered during an experiment. Data = is the information gathered during an experiment. –The more consistent your data, the more valuable it will be for drawing conclusions. –You may need to repeat an experiment to determine whether results are consistent. –If the results are consistent, you may draw valid conclusions from them, inconsistent or confusing results may need to be repeated.

Data Table Understanding, scientists arrange data, they use charts, graphs, tables and explanations. Understanding, scientists arrange data, they use charts, graphs, tables and explanations.  This experiments in this text suggest data tables. Independent variables might be listed along on side of the table and the dependent variables on another.

Reporting Results The scientific method isn’t complete without reporting the results of experimentation. The scientific method isn’t complete without reporting the results of experimentation. –To be accepted among scientists, an experiment must be reproducible. –Other scientists must be able to repeat the experiment –Because scientific questions can be complicated, hypotheses may have to be tested with many experiments to determine whether they are valid. –Some hypothesis are tested for years.

Report Form

Developing and Revising Theories “No amount of experimentation can ever prove me right; a single experiment can prove me wrong.” Albert Einstein “No amount of experimentation can ever prove me right; a single experiment can prove me wrong.” Albert Einstein  A hypothesis that is consistently verified may be established as a theory. Theory = an explanation based on a body of knowledge gained from many observations and supported by the results of many experiments. Theory = an explanation based on a body of knowledge gained from many observations and supported by the results of many experiments.  A hypothesis is a possibility; a theory is a probability.

Conducting Research The scientific method benefits from research, investigating what others have learned about a subject. The scientific method benefits from research, investigating what others have learned about a subject. Every research project starts with a topic Every research project starts with a topic  (pick a topic that interests you, start your questions in the supermarket)  Narrowing the Focus –  Come up with an experiment, or a question that you would like to answer?

Observation Experiments Theory Experiments Revised Theory Hypothesis Revised Hypothesis THE SCIENTIFIC METHOD After you experiment, you might need to revise your theory. This could continue, until you are satisfied with the outcome.

Dairy Products Food and Nutrition Grains Milk in the diet Vitamins and minerals Wheat Lactose intolerance Vitamin C Chemistry of gluten

Finding Information Exploring a new field begins by reviewing already existing literature. Exploring a new field begins by reviewing already existing literature.  To gather information you could start wit the Reader’s Guide to Periodical Literature for recent magazine articles.  Journals such as FDA Consumer, Journal of Food Science, Food Technology, Food Engineering, or Journal of the American Dietetic Association

Questions 1. Describe the value of the scientific method. 2. What is the purpose of a hypothesis in experimentation? 3. Suppose your car stops running and you notice the gas gauge is on “empty.” Write one statement showing inductive reasoning and one showing deductive reasoning based on this event. 4. Name two possible variables in an experiement to test the cleaning ability o two laundry detergents. 5. Why is it unwise to change more than one variable in an experimental trial.

Questions Continued 6. What is the point in repeating an experiment? 7. How is reporting results of experimentation in a journal different from reporting facts in a data table? 8. Why is filling out an experiment report form helpful for learning? 9. Is it considered appropriate to doubt an accepted theory? Explain. 10. Explain which topic would be more suitable for a research paper: the manufacture of steel; or new uses for computers in the manufacture of steel. 11. What people might be helpful as you undertake a food science research project?