Scientific Method How Scientist Work

Types of Science Inductive Reasoning Begins with specific observations & leads to theory Scientific method Deductive Reasoning General to specific Begin with theory & work towards hypothesis http://www.socialresearchmethods.net/kb/dedind.php

Explaining the Evidence Once evidence has been interpreted, scientist try to explain it. A hypothesis is a possible explanation for a set of observations OR an answer to a scientific question. A prediction can be made from a hypothesis. “If________, then ____” statement.

How Scientist Work Designing an experiment involves several steps. Observations Questions Background/research Hypothesis (prediction) Experimentation Conclusions An experiment must be replicated to support findings.

Examples of hypothesis Good Plants will grow taller when given Miracle Grow. Girls will score higher on math tests than boys. Hermit crabs choose colorful shells over non- colored shells. Bad Plants will grow better when given Miracle Grow. Girls are smarter than boys. Hermit crabs like colorful shells. http://www.biologycorner.com/bio1/scimethod.html

Sample Questions Do crickets prefer light or dark? Will ice sink in water? Which will a nail rust faster in?  Salt water or tap water? Do earthworms prefer their soil moist or dry?

Experimenting A controlled experiment involves 2 groups. Experimental Group Observes or measures independent variable (manipulated variable). This is the ONE factor that is changed in the experiment. Control Group Observes or measures dependent variable (a.k.a. responding variable). These are factors that do not change in the experiment.

Example of an Experimental Design Hypothesis: Plants will grow taller when given Miracle Grow. Plants A & B are both given the same amount of light, water, and are stored at the same temperature. Plant A is given Miracle Grow. All the variables are kept constant except the one you are testing. Independent Variable - the factor you change, what you do to your exp. group. (Miracle Grow) Dependent Variable - what happens as a result of that treatment, what you are measuring (height of plant) http://www.biologycorner.com/bio1/scimethod.html

Collecting Data/Evidence A scientist carefully collects and organizes data from the experiment. Data should always be presented in a neat fashion, usually tables or graphs. NO OPINION! http://www.biologycorner.com/bio1/scimethod.html

Conclusion Summarize your finding using evidence from experiment. Was your hypothesis correct/refuted? What are possible errors in experiment? What conclusions can you make based on data table/graphs?

Development of a Theory A theory is a well tested and supported hypothesis. Theories must explain a wide range of observations. Theories can be changed if new evidence presents itself .

Flow Chart http://www.biologycorner.com/bio1/scimethod.html

Types of Observations Qualitative Quantitative Descriptive data using five sense (smell, taste, touch, hear, see) The leaf is green The wool is soft Quantitative Measurable data such as weight, volume, density. The plant height is 5.3 cm The density of water is 1.0g/mL