Methods of Science It comes from the Latin

Methods of Science It comes from the Latin word scientia, meaning "knowledge. "

What is Science? • Science is an organized way of using evidence to learn about the natural world.

What are the Goals of Science? • to investigate and understand nature, to explain events in nature and to use those explanations to make useful predictions.

What do Scientists Do? Scientists collect and organize information in a careful, orderly way looking for patterns and connections between events.

Pure Or Applied Science Pure Science (also called basic science) is gathering of new information or the discovery of a new relationship or fact. It adds to the body of knowledge but does not have to have practical uses.

Not every scientific discovery will have common, everyday applications, but even those that do not, may open up whole new fields of investigation.

Pure science does not have to have a practical purpose. It is for “knowledge sake. ” The information gained in pure science is used to develop new technologies.

• Applied Science – ( also referred to as Technology) the practical use of scientific information. It can lead to the development of new products. or materials that can make our everyday life easier. The new technologies can then be used to investigate new pure science questions.

What are the steps in the scientific method? 1 - Define a problem. (ask a question) First--- It involves making observations. 2 - Research the problem.

3 - Formulate a hypothesis a testable explanation or prediction – it may be thought of as a possible explanation for a set of observations, or an answer to a scientific question. 4 - Design an experiment to test the hypothesis. 5 - Make observations and record data. If observations involve numbers, they are quantitative, otherwise they are qualitative.

6 - Analyze data and draw conclusion. 7 - Publish or report the results.

Scientific Models • A model is a pattern, plan, representation, or description designated to show the structure or workings of an object, system, or concept. – Serway/Faughn Physics pg 6 UTexas. Edu Everyday Models Model What the model represents Cake recipe Process of making a cake Chapter title Chapter contents News article about Chicago Cubs' latest loss The game itself Road map of Madison, Wisconsin Paths of transit in Madison Household budget Household expenses and income a statistical average something close to what can be expected

• The model is the most basic element of the scientific method. Everything done in science is done with models. • A model is any simplification, substitute or stand-in for what you are actually studying or trying to predict. The USDA food pyramid, which recommends the proportions of different kinds of foods in a healthy diet, is a model of the thousands of scientific studies that have been undertaken on the relation among cancer, heart disease and diet.

• The periodic table of the elements is a model chemists use for predicting properties of the elements.

• USDA Food Pyramid Model has been replaced with My Plate Model

• Physicists use Newton's law to predict how objects will interact, such as planets and spaceships.

• In geology, the continental drift model predicts the past positions of continents.

• a globe is a physical model of the earth • Watson and Crick are scientists who developed a physical model of DNA

• There are computer models for weather systems and climate. • Many models currently used in physics are mathematical.

Experimental Variables • Variables - something that changes

Independent Variable (manipulated) • changed by the experimenter. An experiment can have only one. It is the only factor that affects the outcome of the experiment.

Dependent Variable (responsive) it changes in response to the independent variable (It changes because of what the experimenter changed while conducting the experiment)

The hypothesis usually shows the relationship between the independent and dependent variables. If independent variable, then dependent variable. (Example: If the rats consume large amounts of sweetener, then they will develop brain chemicals that cause mood changes. )

Constants (controls) Things kept the same by the experimenter. A good experiment has many.

Control or Control group • the object or group that is not given the experimental treatment. It is used as a standard for comparison in the experiment

Experimental group • the test group that receives the experimental treatment A fake medicine is called a placebo and is given to the control group instead of the real one. Trial a repeated procedure in the experiment

Theory A broad and comprehensive statement accepted to be true, supported by considerable experimental evidence, resulting from many tests. It may tie together related hypotheses. It involves facts, and can involve scientific laws, inferences, and tested hypotheses.

As more information is gained, and new facts cannot be explained by present theories, those theories may be changed or replaced by new theories. (They are always being questioned and examined)

To be valid, a theory must continue to pass several tests: • A theory must explain observations simply and clearly. • Experiments that illustrate theory must be repeatable. (Some theories are impossible to test by laboratory experiments, such as continent movement because the events happen over such long periods of time) • You must be able to predict from theory.

• Many people use the word theory in their everyday language to mean a “guess. ” • When the word theory is used in science, it represents much more that just a guess.

Scientific law It describes a relationship in nature that is observed to be a recurring pattern of events, such as the existence of gravity, or laws of motion.

A Scientific law is a summary of an observed event and states a repeated observation about nature. It is not used to explain an occurrence in nature. A scientific law may be useful in forming a theory.