1.3: Scientific Thinking & Processes Key concept: Science is a way of thinking, questioning, and gathering evidence. • Science is a process of trying to understand the world around us using critical and logical thinking to evaluate results and conclusions. • Scientists gather evidence and share their findings with one another. • Observation: the use of our senses, computers, and other tools to gather information about the world. • Ex.: Studying the interactions between gorillas by observing their behavior. Observations can be recorded as data to be analyzed • Qualitative data: Descriptions of phenomena that can include sights, sounds, and smells. • Quantitative data: Characteristics that can be measured or counted such as mass, volume, and temperature; Numbers Scientists use observations and data to form hypotheses • Hypothesis: A proposed, testable answer to a scientific question. • Formal hypotheses are usually written in an “if, then, because” format. • If (change of IV) then (change of DV) because (why you think this will happen). • If I change the light bulb then my light will work because the bulb was bad and I replaced it. • If I increase my blood pressure medicine then my blood pressure should come down because I still suffered from high blood pressure. How do scientists test hypotheses? • The scientific method • A) Observe and ask questions that lead to a problem • B) Form a hypothesis • C) Test the hypothesis with a controlled experiment by making observations and gathering data. • D) Analyze gathered data • E) Reject (start over at step B) or Accept your hypothesis. • F) Form a conclusion • This is what you will do every time you conduct a lab in this class!!!!! How do scientists test hypotheses? • Controlled experiments study the effect of independent variables on dependent variables. • Independent variable: A condition that is manipulated, or changed, by a scientist. Effects are measured by changes in dependent variables. • Dependent variable: observed and measured during an experiment. • Example: Testing medication to treat blood pressure. IV: medication dose, DV: blood pressure. Controlled experiments • Only one independent variable should be changed in an experiment. • Other conditions must stay the same and are called constants. • Controlled experiments must have a control group – everything is the same as the experimental groups but the independent variable is not manipulated. • Example: When testing blood pressure medication, control group receives none of the active ingredient. • A large number of test subjects or trials is ideal. Other important science terms • Inference: A conclusion reached on the basis of evidence and reasoning. (Ex: you make an inference when you use clues to figure something out). Ex: Murder mystery book • Law: A law that generalizes a body of observations. At the time it is made, no exceptions have been found to a law. It explains things but does not describe them; serves as the basis of scientific principles. (Ex: Law of Gravity, Newton’s Laws of motion). • Theory: A proposed explanation for observations and experimental results that is supported by a wide range of evidence – may eventually be accepted by the scientific community. (Ex: Big Bang Theory, Evolution & Natural Selection) • Principle: A concept based on scientific laws and axioms (rules assumed to be present, true, and valid) where general agreement is present. (Ex: Buoyancy Principle) • Fact: An observation that has been repeatedly confirmed.