Scientific Method and Graphing

The Scientific Method The scientific method is the procedure consisting of systematic observation, measurement, experimenting, and the formation and testing of a hypothesis. There are 5 main components to the scientific method: Observation, questions, hypothesis, experimentation, and conclusions

1st Step: Observation Observation is taking notice of a problem or unusual event. Ex. In 1976 , a deadly pathogen (Ebola) appeared in the Congo. The doctors observed symptoms and the locations of cases of this pathogen to determine the cause and how it was spread.

2nd Step: Question All investigations begin with question in order to determine what needs to be investigated further. Ex. How was the disease transmitted? What is the disease causing agent?

3rd Step: Hypothesis The hypothesis is the suggested explanation or prediction for an observation or question. The hypothesis is worded as a statement that is testable. The hypothesis can be supported or rejected by data but NEVER proven. The hypothesis should be stated in the If…then..” format. Ex. If the virus were the true disease causing agent, then introducing the virus into healthy tissue would cause cell death.

4th Step: Experimenting Experiments are designed to test a hypothesis by gathering data in controlled conditions. There are many aspects to take note of when conducting an experiment. Every experiment must have a control and experimental group, an independent and dependent variable, collection of data to be analyzed in respect to the hypothesis.

Control Group Vs. Experimental Group A control group serves as a standard of comparison with another group; this group is not subjected to what is tested. An experimental group serves as the group that is subjected to what is tested.

Independent Variable Vs. Dependent Variable An independent variable is the one thing that is different between the two groups. A dependent variable is the measured results of the experiment. How does the IV affect the DV ?

Experimenting Example Group A kidney cells exposed to infected blood Group B kidney cells not exposed to infected blood Scientists observed cells’ health over many days Group A kidney cells died What is the independent Variable? What is the dependent variable? What is the control group? What is the experimental group?

Collecting Data Collecting Data is the longest phase of the scientific investigation as information is gathered to answer the hypothesis. Collecting data has four main requirements such as observing, measuring, sampling, and organizing. Observing is qualitative data with the recording of unusual events that raise questions. Measuring is quantitative data dealing with all of the numbers. Sampling represents using a large and random sample to represent the entire population. Organization is used to organize the collected data into charts, tables, and graphs.

Step 5: Drawing Conclusions Conclusions are drawn from the collected data and can be expressed through modeling, inferring, and forming a theory. Modeling is the explanation of the conclusion supported by the data. Inferring is the conclusion made based on raw data. Forming a theory is the comprehensive statement of what is thought to be true. Example: The Ebola fever is a virus that was transmitted with close contact with the infected victim.

Report Your Findings! After drawing your conclusions, report your findings. Your findings can be reported in a lab report, journal article, announced on the media, or published in a book.

Why is graphing important in science? Graphing is used by scientists to display the data that is collected during an experiment. When a graph is put together incorrectly, it detracts the reader from understanding the data you collected.

Most graphs contain 5 major parts: 1. Title - describes what the graph is about and tells the reader what to expect 2. X-axis - depicts the independent variable that can be controlled by the experimenter 3. Y-axis – depicts the dependent variable that is affected directly by the independent variable 4. Scaling for each variable – scaling/numbering must be consistent and must take up a conservative amount of space 5. Legend – short descriptive narrative concerning the graph’s data

Types of Graphs Bar Graphs – used to compare amounts Line Graphs – used to show the change of one piece of information as it relates to another change

Bar Graph Example What is the independent variable? What is the dependent variable? What is the appropriate title? What is the average number of deer per month?

Line Graph Example #1 What is the independent variable? What is the dependent variable? What is the appropriate title? What is the average number of deer per month?

Line Graph Example #2 What is the independent variable? What is the dependent variable? What is an appropriate title? Was a legend necessary for this data?

What is happening Here? What is on the X axis? What is on the Y axis? Why are the data points on the X axis spaced unevenly? Interpret this graph.

What is on the X axis? Is this the dependent or independent variable? What is on the Y axis? Why is a line graph the right type of graph for this data? Interpret this graph.

What is on the X axis? What is on the Y axis? Can you think of any changes in school or society that account for the data between 1980 and 2001? Can you think of any changes in school or society that account for the data after 2010? What is the difference between correlation and causation?