THE SCIENTIFIC PROCESS

Chapter Three: The Scientific Process  3.1 Inquiry and the Scientific Method  3.2 Experiments and Variables  3.3 The Nature of Science and Technology

Section 3.1 Learning Goals  Apply deductive reasoning skills to solve problems.

 Contrast hypotheses, theories, and laws.

 Explore the scientific process and apply steps of the scientific method.

 3.1 Inquiry and the Scientific Method Scientists believe the universe follows a set of rules called

natural laws.

 The primary goal of science is to discover these natural laws and what they mean.

 3.1 Inquiry and the Scientific Method Learning about science by asking questions is called

inquiry

.  An inquiry is like a crime investigation with a mystery to solve.

  3.1 Inquiry and the Scientific Method Because

evidence

is so important in science, there are careful rules defining what counts as scientific evidence.

The evidence must accurately describe what happens in the real world.

   3.1 Scientific Evidence Scientific evidence must be

objective

. “Objective” means the evidence should describe

only what actually happened

as exactly as possible. It is reported without bias or opinion.

3.1 Scientific Evidence  Scientific evidence must

repeatable.

Galileo’s drawings of the moon.

 “Repeatable” means 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 Scientific evidence may include numbers, tables, graphs, words, pictures, sound recordings, or other information.

It is important that scientific evidence be communicated clearly, with no room for misunderstanding.

  3.1 Inquiry and the Scientific Method A

scientific theory

is a human attempt to describe a natural law.

For example, understanding heat puzzled people for a long time.

3.1 Scientific theories  Before 1843, scientists believed (a theory) that heat was a kind of fluid (like water) that flowed from hotter objects to colder objects.  They called this fluid

caloric

.

 The caloric theory explained what people knew at the time.

3.1 Scientific theories  However, a big problem came up when people learned to measure weight accurately.

 The 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 discovered.

not

explain the new evidence so a new (or improved) theory is waiting to be

 3.1 Scientific theories The word of time.

theory

in science means a single explanation is supported by lots of evidence collected over a long period  Theories in science start out as

hypotheses

.

3.1 Scientific hypotheses  A

scientific hypothesis

must be testable.  We collect evidence that supports or refutes the hypothesis.

3.1 Scientific experiments  Experiments done by James Joule in 1843 were confirmed over many years and became the

theory

of heat we accept today.

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

1.

3.1 The Scientific Method 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 3A Measuring Time 

Key Question: How is time measured accurately?

Chapter Three: The Scientific Process  3.1 Inquiry and the Scientific Method  3.2 Experiments and Variables  3.3 The Nature of Science and Technology

Section 3.2 Learning Goals  Define experiment.

 Contrast experimental and control variables.

 Discuss how experiments are carried out and the importance of communicating results.

Investigation 3B Experiments and Variables 

Key Question: How do you design a valid experiment ?

3.2 Experiments and variables  An

experiment

specifically set up to investigate something.

is a situation  The goal of any experiment is to understand the relationship between variables.

 In a simple ideal experiment only one variable is changed at a time.

3.2 Experiments and variables  The variable you change in an experiment is called the

experimental variable

.

 The variables you keep the same are called

control variables

.

 Each time you run the experiment is called a

trial

.

 See if you can identify each component in this experiment…

Trials Control variable Experimental variable Control variable Control variable

3.2 Experimental techniques  Your

experimental technique

is how you actually do the experiment.

 The

procedure

to do an experiment.

is a collection of all the techniques you use

3.2 Experiments then and now  Michael Faraday , a British scientist, made some important discoveries while experimenting with electricity and magnets.  Faraday’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  Earth is like a giant magnet.

 In 1996, NASA conducted a modern version of Faraday’s electromagnetism experiments using a tethered satellite.

Chapter Three: The Scientific Process  3.1 Inquiry and the Scientific Method  3.2 Experiments and Variables  3.3 The Nature of Science and Technology

Section 3.3 Learning Goals  Examine the importance of ethics in scientific research and reporting.

 Discuss examples of how science helps to solve problems.

 Consider the role of engineering in scientific and technological advancements.

3.3 The Nature of Science and Technology  Truthful reporting is the most important tradition of science.

 Scientists often write a report of their experiments and submit it to a

scientific journal

.

3.3 The Nature of Science and Technology 

Technology

is the application of science to meet human needs and solve problems.

 Technology arises from a need for things to be done better.

3.3 Science and Technology  People who design technology to solve problems are called

engineers

.

3.3 The Nature of Science and Technology  1.

2.

3.

4.

The

engineering cycle

consists of: designing a prototype building a prototype, testing a prototype, and evaluating a prototype.

 The best inventions go through the cycle many times, being improved each cycle until all the problems are worked out .

Investigation 3C Looking for Significant Differences 

Key Question: Do you really need photogates to study the motion of the Energy Car, or is a stopwatch good enough?

Ethics in Medical Research  In 1990, Seldane ranked fifth in new prescriptions dispensed in the United States. It was used to treat allergy symptoms without inducing drowsiness.

 Doctors suspected that an interaction between Seldane and another drug might cause unusual heart rhythms and unexplained fainting.