THE SCIENTIFIC PROCESS Chapter Three The Scientific Process

THE SCIENTIFIC PROCESS

Chapter Three: The Scientific Process Ø 3. 1 Inquiry and the Scientific Method Ø 3. 2 Experiments and Variables Ø 3. 3 The Nature of Science and Technology

Section 3. 1 Learning Goals ØApply deductive reasoning skills to solve problems. ØContrast hypotheses, theories, and laws. ØExplore the scientific process and apply steps of the scientific method.

3. 1 Inquiry and the Scientific Method Ø Scientists believe the universe follows a set of rules called natural laws. Ø The primary goal of science is to discover these natural laws and what they mean.

3. 1 Inquiry and the Scientific Method Ø Learning about science by asking questions is called inquiry. Ø An inquiry is like a crime investigation with a mystery to solve.

3. 1 Inquiry and the Scientific Method Ø Because evidence is so important in science, there are careful rules defining what counts as scientific evidence. Ø The evidence must accurately describe what happens in the real world.

3. 1 Scientific Evidence Ø Scientific evidence must be objective. Ø “Objective” means the evidence should describe only what actually happened as exactly as possible. Ø It is reported without bias or opinion.

3. 1 Scientific Evidence Ø Scientific evidence must repeatable. Ø “Repeatable” means Galileo’s drawings of the moon. that others who look the same way at the same thing will observe the same results. More evidence of lunar cycles.

3. 1 Inquiry and the Scientific Method Ø Scientific evidence may include numbers, tables, graphs, words, pictures, sound recordings, or other information. Ø It is important that scientific evidence be communicated clearly, with no room for misunderstanding.

3. 1 Inquiry and the Scientific Method Ø A scientific theory is a human attempt to describe a natural law. Ø For example, understanding heat puzzled people for a long time.

3. 1 Scientific theories ØBefore 1843, scientists believed (a theory) that heat was a kind of fluid (like water) that flowed from hotter objects to colder objects. ØThey called this fluid caloric. ØThe caloric theory explained what people knew at the time.

3. 1 Scientific theories ØHowever, a big problem came up when people learned to measure weight accurately. ØThe caloric theory was soon given up because it could not explain this new evidence.

3. 1 Scientific theories One of two things can happen when new evidence is found: 1. The current theory correctly explains the new evidence. Or, 2. The current theory does not explain the new evidence so a new (or improved) theory is waiting to be discovered.

3. 1 Scientific theories Ø The word theory in science means a single explanation is supported by lots of evidence collected over a long period of time. Ø Theories in science start out as hypotheses.

3. 1 Scientific hypotheses ØA scientific hypothesis must be testable. ØWe collect evidence that supports or refutes the hypothesis.

3. 1 Scientific experiments ØExperiments done by James Joule in 1843 were confirmed over many years and became theory of heat we accept today.

3. 1 Scientific theories ØA hot cup of coffee has more heat energy than a cold cup of coffee. ØAs coffee cools, it’s heat energy is transferred to the room. ØAs a result, air in the room is warmed, but no change in weight or mass can be detected in the two cups.

3. 1 The Scientific Method 1. Scientists observe nature, then develop or revise hypotheses about how things work. 2. The hypotheses are tested against evidence collected from observations and experiments. 3. Any hypothesis that correctly accounts for all of the evidence from the observations and experiments is a potentially correct theory. 4. A theory is continually tested by collecting new and different evidence. Even one piece of evidence that does not agree with a theory forces scientists to return to step one.

Investigation 3 A Measuring Time ØKey Question: How is time measured accurately?

Chapter Three: The Scientific Process Ø 3. 1 Inquiry and the Scientific Method Ø 3. 2 Experiments and Variables Ø 3. 3 The Nature of Science and Technology

Section 3. 2 Learning Goals ØDefine experiment. ØContrast experimental and control variables. ØDiscuss how experiments are carried out and the importance of communicating results.

Investigation 3 B Experiments and Variables ØKey Question: How do you design a valid experiment?

3. 2 Experiments and variables ØAn experiment is a situation specifically set up to investigate something. ØThe goal of any experiment is to understand the relationship between variables. ØIn a simple ideal experiment only one variable is changed at a time.

3. 2 Experiments and variables ØThe variable you change in an experiment is called the experimental variable. ØThe variables you keep the same are called control variables. ØEach time you run the experiment is called a trial. ØSee if you can identify each component in this experiment…

Experimental variable Trials Control variable

3. 2 Experimental techniques ØYour experimental technique is how you actually do the experiment. ØThe procedure is a collection of all the techniques you use to do an experiment.

3. 2 Experiments then and now ØMichael Faraday, a British scientist, made some important discoveries while experimenting with electricity and magnets. ØFaraday’s original question was “How are electricity and magnetism related? ” Electric current is created when a coil rotates in a magnetic field.

3. 2 Experiments then and now ØEarth is like a giant magnet. ØIn 1996, NASA conducted a modern version of Faraday’s electromagnetism experiments using a tethered satellite.

Chapter Three: The Scientific Process Ø 3. 1 Inquiry and the Scientific Method Ø 3. 2 Experiments and Variables Ø 3. 3 The Nature of Science and Technology

Section 3. 3 Learning Goals ØExamine the importance of ethics in scientific research and reporting. ØDiscuss examples of how science helps to solve problems. ØConsider the role of engineering in scientific and technological advancements.

3. 3 The Nature of Science and Technology ØTruthful reporting is the most important tradition of science. ØScientists often write a report of their experiments and submit it to a scientific journal.

3. 3 The Nature of Science and Technology ØTechnology is the application of science to meet human needs and solve problems. ØTechnology arises from a need for things to be done better.

3. 3 Science and Technology ØPeople who design technology to solve problems are called engineers.

3. 3 The Nature of Science and Technology Ø The engineering cycle consists of: 1. designing a prototype 2. building a prototype, 3. testing a prototype, and 4. evaluating a prototype. Ø The best inventions go through the cycle many times, being improved each cycle until all the problems are worked out.

Investigation 3 C Looking for Significant Differences ØKey Question: Do you really need photogates to study the motion of the Energy Car, or is a stopwatch good enough?

Ethics in Medical Research ØIn 1990, Seldane ranked fifth in new prescriptions dispensed in the United States. It was used to treat allergy symptoms without inducing drowsiness. ØDoctors suspected that an interaction between Seldane and another drug might cause unusual heart rhythms and unexplained fainting.