What is Scientific Inquiry? SCIENCE Science assumes the natural world is Consistent Predictable Goals of science are To discover patterns in nature To use knowledge to predict
Two Types of Science PURE SCIENCE studying things for the sake of gaining knowledge New discoveries APPLIED SCIENCE The use of science in practical ways Technology
Limitations of Science Science cannot make value judgments Should we use embryonic stem cells for research? Science cannot prove something doesn’t exist (universal negative) Are mermaids real? Scientific investigation is as limited as the instruments we use Can you study Pluto with binoculars? Scientific investigation is limited by the knowledge we already have Copernicus couldn’t prove why his theory of planetary motion was correct because calculus hadn’t been invented yet – but he was correct!
Scientific Vocabulary Facts – things that are observable and indisputable Data – any piece of information; usually gained through observation and experimentation Laws – statements that describe patterns in nature with no known exceptions. Theories – explanations usually based on evidence (may be wrong) Models – man-made representations to help us visualize scientific concepts
Hypothesis and Theory An idea can become a Hypothesis – tentative or untested explanation Theory – tested, confirmed, supported hypothesis Scientific Method Ask a question Gather facts through observation Formulate hypotheses Test hypotheses to formulate theories Analyze you data Draw conclusions based on results
Science Methods Scientific knowledge is gained through following systematic steps: State a problem or question to be answered Collect facts Develop a hypothesis Conduct experiments Analyze data Reexamine the hypothesis and accept, modify or reject it
Scientific Experimentation An experiment is a controlled test to find the answer to a question. Only one condition in an experiment is change at a time: The conditions that affect the outcome are called variables Independent variable – the one changes by the experimenter Dependent Variable – the condition that changes in response to the independent variable Factors that do not change in an experiment are called constants.
Scientific Experimentation Experiments have two parts: Control group – group under normal conditions (nothing unusual done to it) Experimental group – the test group in which a variable is changed The goal of an experiment is to predict what might happen in similar situations.
Scientific Method QUESTION – What do you want to know? RESEARCH – Gather information HYPOTHESIS – An educated guess as to the answer to the question EXPERIMENT – written and carefully followed step- by-step procedure designed to test the hypothesis ANALYSIS – written description of information obtained and observations made during the experiment CONCLUSION – Was the hypothesis correct or incorrect? What did you learn?
Accuracy v. Precision ACCURACY How close a measurement is to the true value. Ex: in target shooting a high score indicates nearness to the bull’s eye and a high degree of accuracy. PRECISION Degree to which several measurements provide answers very close together so you know your data is reliable. Ex: measurements of an object that are 12.01cm, 12.00cm, 11.99cm and 12.00cm are fairly precise.
Accuracy v. Precision One can say that a measurement is accurate but not precise; precise but not accurate; neither or both. An example of bad precision and good accuracy can be: Suppose a lab refrigerator holds a constant temperature of 38.0 F. A temperature sensor is tested 10 times in the refrigerator. The temperatures from the test yield the temperatures of: 37.8, 38.3, 38.1, 38.0, 37.6, 38.2, 38.0, 38.0, 37.4, 38.3. This distribution shows no impressive tendency toward a particular value (lack of precision) but each value does come close to the actual temperature (high accuracy).temperature
Accuracy v. Precision Write a problem where measurements are: 1. precise but not accurate 2. accurate but not precise 3. neither accurate nor precise 4. both accurate and precise Be prepared to share your problems with the class.