The Nature of Science
Chapter 1: What is Science?
Chapter 2: Science in Action
Chapter 3: Models in Science
Chapter 4: Evaluating Scientific
Explanation
What is Science Science – a way of learning about the
natural world Scientists ask questions about the natural
world, but questions about art, politics, personal preferences, or morality can’t be answered by science.
Answers are uncertain because new knowledge and discoveries are continually being made
What is Science? Scientific theory: An attempted
explanation for repeatedly observed patterns in the natural world
A rule that describes a pattern in nature is a scientific law (doesn’t explain the “why”)
Systems in Science Scientists study systems – collections of
structures, cycles, and processes that relate to and interact with each other All systems are made up of other systems
THREE branches of Science Life Science – studies living things and how they
interact….examples??? Earth and space systems are studied in Earth Science Physical science studies matter and energy The practical use of science is called technology
Discussion Question What is the difference between a scientific
theory and a scientific law?
A scientific theory explains, and a scientific law describes.
Science in Action The scientific method includes observing,
questioning, and researching; forming an hypothesis; predicting an outcome; investigating; analyzing; forming conclusions, communicating findings; and repeating the process
Scientists infer conclusions based on observations.
Controlled Experiment One type of scientific investigation Factors that can be changed in an
experiment are called variables Constants are variables that remain
unchanged Safety is important or both laboratory and
field scientists
Scientific Processes and Methods 1. Observations/Questioning 2. Measuring, Organizing Data, and
Classifying 3. Hypothesizing -- a testable explanation
based on experience, reading, and/or previous experiments. (NOT A GUESS)
4. Predicting -- stating in advance the result that will be obtained from testing
Scientific Method, cont. 5. Experimenting -- A controlled procedure for
testing a hypothesis Control Group -- all conditions remain constant Experimental Group -- same as control, except for
ONE factor Variable
Independent Variable - condition that changes Dependent Variable - response to changed condition
Data Qualitative ~ descriptive Quantitative ~ numbers
Scientific Method, cont. 6. Analyzing Data
7. Inferring Conclusions (concluding from evidence collected during experimentation)
8. Modeling and Communicating
9. Test and Re-test ~ law or theory formed
Scientific Method, cont. LAW -- general statement that describes a
wide variety of phenomena If a hypothesis describes HOW things happen
and continues to be supported by evidence, it becomes a law.
THEORY -- most probable explanation for a set of data based on best available evidence If a hypothesis describes WHY things happen
and continues to be supported by evidence, it becomes a theory.
Scientific Method -- Example Observations:
Fish populations in Twin Lakes are declining.
The pH (acidity) of the water in the lakes is dropping to 4.2.
One hundred miles west of Twin Lakes is a power plant that is burning tons of coal every year, releasing sulfur dioxide into the air.
Questioning/Hypothesizing
Question: Is there a link between the power plant, the pH of the lake, and the fish decline?
Hypothesis: If acid rain falling on Twin Lakes is related to fish reproduction, then increasing acid rain amounts will cause the fish to have poor reproduction.
Experiment Experiment
Twin Lakes is a lake in the mountains that can be divided by a barrier.
A complete inventory will gather baseline data.
One arm of the lake, on the east side of the barrier, will be treated with sulfuric acid to reduce the pH to 4.0.
The west arm of the lake will be left alone, other than monitoring.
Experiment
West Branch
Twin Lakes -- Acid Rain Problem
East Branch
Power Plant
100 miles
No Acid Added Acid Rain Added
Barrier
Conclusion The power plant emits sulfur dioxide into
the air which combines with rain to produce acid rain. The addition of this acidic rain to the lakes lowers the pH and causes the fish to stop reproducing. This results in declining fish populations and jeopardizes the survival of the fish.
Models in Science Model – representation of an object or event used
as a tool for understanding the natural world. Models come in THREE basic types:
Physical models can be seen and touched. Computer models can be seen on a computer screen
but not touched. Idea models are concepts that describe how someone
thinks about something in the natural world.
Model Uses Models communicate observations and
ideas Models can test Predictions Models can save time, money, and lives
Can you think of any of these?? Models change over time as new observations
and discoveries are made.
Evaluating Scientific Explanation Critical thinking- using what is known to
decide if new facts should be agreed with or believed
Evaluating the Data Data should be specific and exact Observations should be carefully, accurately,
and completely noted ~science journal Data must be repeatable to be reliable