SCIENTIFIC METHOD 1.3

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Ralf McKenzie
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1 SCIENTIFIC METHOD 1.3 Curiosity leads us to ask questions about Life. Science provides a way of answering such questions about the natural worlds. Science is a systematic method that involves forming and testing hypotheses. More importantly, science relies on evidence, not beliefs, for drawing conclusions. OBJECTIVES: 1. Outline the main steps in the Scientific Method. 2. Summarize how observations are used to form hypotheses. 3. Lists the elements of a controlled experiment. 4. Describe how scientists use data to draw conclusions. 5. State how communications in science helps prevent dishonesty and bias. Science as a Process 1. Science is characterized by an organizational approach, called the Scientific Method, to learn how the natural world works. The methods of science are based on Two Important Principles: A. That events in the natural world have natural causes not supernatural causes. B. Uniformity - is the idea that fundamental laws of nature operate the same way at all places at all times. 2. Science has some unique features that make it different from other fields of study. One of those features is a Sequence of Logical Steps to generate new ideas, answer questions, and draw conclusions. This is how a scientist tries to solve a problem or answer a question. 3. The Characteristic Steps in a scientific inquiry are commonly called THE SCIENTIFIC METHOD. The Steps of Scientific Method are: A. The process of science begins with an Observation. An Observation is the act of perceiving a natural occurrence that causes someone to pose a question. B. One tries to answer the question by forming Hypotheses. A hypothesis is a proposed explanation for the way a particular aspect of the natural world functions. A hypothesis is also known as and educated guess to explain the observation. C. A Prediction is a statement that forecasts what would happen in a test (experiment) situation if the hypothesis were true. A Prediction is recorded for each hypothesis.

2 D. An Experiment is used to test a hypothesis and its predictions. E. Once the experiment has been concluded, the data are analyzed and used to draw conclusions. F. After data have been analyzed, the data and conclusions are Communicated to scientific peers and to the public. This way others can verify, reject, or modify the researcher's conclusions. A. OBSERVING and ASKING QUESTIONS 1. The process of scientific method generally begins with and unexplained observation about nature. Sometimes, making observation requires little more than carefully looking at an objective. Scientist have many tools to help with observing, the Microscope and Medical Equipment are examples. 2. ALL SCIENTIFIC INVESTIGATIONS BEGINS WITH ONE OR MORE QUESTIONS. 3. The questions come from the Observations made. B. FORMING A HYPOTHESIS 1. When scientist have made Many Observations and Collected Sufficient Data, a biologist lists possible answers to a scientific question - Hypothesis. This Explanation, called a HYPOTHESIS, IS A STATEMENT THAT BOTH EXPLAINS THEIR OBSERVATIONS AND DATA AND CAN BE TESTED. 2. A Statement (Hypothesis) is testable if evidence can be collected that either supports it or disproves it. 3. A Hypothesis may be shown to be wrong, but it can NEVER be proved TRUE beyond all Doubt. It can only be supported by evidence. Scientists often must refine and revise their original hypothesis - or even discard them - as they uncover new evidence. 4. To TEST a hypothesis, scientist make a PREDICTION that logically follows from the hypothesis. A prediction is what is expected to happen if each hypothesis were true. 5. A PREDICTION is a Statement made in advance that states the results that will be obtained from testing a hypothesis, if the hypothesis is TRUE. A prediction most often takes the form of an "IF - THEN" Statement.

3 C. DESIGNING AN EXPERIMENT 1. An Hypothesis is often tested by carrying out an EXPERIMENT. 2. EXPERIMENTING IS THE PROCESS OF TESTING A HYPOTHESIS OR PREDICTION BY GATHERING DATA UNDER CONTROLLED CONDITIONS. 3. ALL experiments have Variables - a factor that can change in an experiment. Temperature, length of time, size, and chemical composition are possible variables. 4. A CONTROLLED EXPERIMENT is based on a Comparison of a Control Group with an Experimental Group. The Control Group and the Experimental Group are designed to BE IDENTICAL EXCEPT for ONE FACTOR the Independent Factor. 5. The one factor being Tested is called the INDEPENDENT VARIABLE OR EXPERIMENTAL VARIABLE, ALL OTHER VARIABLES MUST BE CONTROLLED. 6. During the course of a controlled experiment, a scientist observes or measures another factor in both the control group and the experimental group. This factor is called the DEPENDENT VARIABLE - dependent because it is driven by or results from the Independent Variable. 7. After the experiment, the data collected must be organized and analyzed to determine whether data are reliable and weather they support or do not support a hypothesis or prediction. D. COLLECTING AND ANALYZING DATA 1. The LONGEST PHASE of a scientific investigation is usually data collection. 2. DATA include any and all information that scientist gather to answer their questions. 3. There are FOUR Important aspect to collecting Data: OBSERVING, MEASURING, SAMPLING, AND ORGANIZING DATA. A. OBSERVING - It is the observation of something unusual or unexplained that raises the first question. Observation typically employs one or more of the FIVE SENSES to perceive objects or events. Most observation in a scientific investigation are Direct. B. MEASURING - Many kinds of observations involve QUANTITATIVE DATA - Data that can be measured. (1). Scientist may measure the dimensions of an object, the number

4 of objects in a group, the duration of an event, or other characteristics in precise units. C. SCIENTIFIC SAMPLING is the technique of using a Sample, that is, a small part, to represent an entire population. To be useful, samples must by LARGE AND RANDOM - they should include as many subject as possible, and scientist must be sure to sample a Cross Section of the Population so that an accurate representation is obtained. D. ORGANIZING DATA - Data are of little use unless they are organized. Organizing Data involves placing observations and measurements in some kind of logical order, in a graph, chart, table, or map. E. DRAWING CONCLUSIONS - MODELING, INFERRING, OR FORMING A THEORY 1. The GOAL of Scientific Investigation is to shed light on something previously not understood. 2. THE FINAL STEP OF MOST INVESTIGATIONS IS TO PRODUCE A MODEL. Modeling involves constructing a representation of an object, a system, or a process that helps show relationships among data. A MODEL IS ESSENTIALLY AN EXPLANATION SUPPORTED BY DATA. It can be Visual, Verbal, or Mathematical. 3. INFERRING - An Inference is a conclusion made on the basis of facts or premises rather than on direct observations. IF YOU SEE SMOKE, YOU WILL PROBABLY INFER THAT ITS SOURCE IS FIRE, EVEN IF YOU CAN'T SEE THE FIRE. An inference is not directly testable 4. FORMING A THEORY - A Theory may formed after many related Hypotheses have been Tested and Supported with much experimental evidence. A Theory is a broad and comprehensive statement of what is THOUGHT TO BE TRUE. 5. COMMUNICATING IDEAS A. The final Step of Scientific Method is to communicate your findings and to share your results of your studies with others. Communication allows scientist to test and build on the work of others.b. Two ways to communicate your findings are to publish your finding in scientific journals or present them at scientific meetings. B. Two ways to communicate your findings are to publish your finding in scientific journals or present them at scientific meetings.

Name Class Date. In the space provided, write the letter of the description that best matches the term or phrase.

Name Class Date. In the space provided, write the letter of the description that best matches the term or phrase. Skills Worksheet Concept Review MATCHING In the space provided, write the letter of the description that best matches the term or phrase. 1. control group 2. prediction 3. physical model 4. risk 5. conceptual