Unit 1: Scientific Method
Theory
A scientific theory summarizes a hypothesis or group of hypotheses that have been supported with repeated testing. A theory is valid as long as there is no evidence to dispute it. Therefore, theories can be disproven. One definition of a theory is to say it's an accepted hypothesis.
Control Variables
A variable that remains unchanged or held constant to prevent its effects on the outcome of an experiment. May verify the behavior of and the relationship between independent and dependent variables. Control variables are important in scientific experiments to test the validity of the results.
Precision
Also called reproducibility or repeatability, how close two or more measurements are to each other. A group of measurements can be precise, but the measurements may not be accurate.
Observation
(1) The act of attentive watching, perceiving, or noticing. The use of the senses to obtain information. (2) involves making measurements and collecting data that can be qualitative or quantitative
Dependent (responding) Variable
(1) The variable in an experiment whose value is influenced by, an independent variable. (2) A factor whose value changes when the independent variable is changed. (3) The variable whose value is measured to determine the extent of the effect of another variable to it, as in an experiment.
Independent (Manipulated) Variable
(1) The variable in an experiment whose value is not affected by other variables. (2) The variable that is manipulated in an experiment by the scientist (3) The factor that affects the value of variables dependent to it.
Control Group
A group in a scientific experiment where the factor being tested is not applied so that it may serve as a standard for comparison against another group where the factor is applied. In the above example, the plants on the left are the control group, they did not receive any fertilizer. The plants on the right received a fertilizer. This shows that the fertilizer did increase the growth of the plants when compared to the control group.
Hypothesis
A hypothesis is a tentative and testable explanation, based on observation(s). A hypothesis can be supported or refuted through experimentation or more observation. A hypothesis can be disproven, but not proven to be true.
Law
A law generalizes a body of observations. At the time it is made, no exceptions have been found to a law. Scientific laws explain things, but they do not describe them. One way to tell a law and a theory apart is to ask if the description gives you a means to explain 'why'. Example: Consider Newton's Law of Gravity. Newton could use this law to predict the behavior of a dropped object, but he couldn't explain why it happened.
Scientific Method
A logical approach to solving problems by observing and collecting data, formulating hypotheses, testing hypotheses and formulating theories that are supported by data.
Qualitative
Data that is descriptive but doesn't actually measure the attributes of a thing or a phenomenon. It describes data as compared to quantitative data that tends to calculate data.
Quantitative
Data that is used to describe a type of information that can be counted or expressed numerically. This type of data is often collected in experiments, manipulated and statistically analyzed. Quantitative data can be represented visually in graphs, histograms, tables and charts.
Accuracy
How close a measurement is to the correct of acceptable value. In the laboratory, accuracy of a test is determined when possible by comparing results from the test in question with results generated from an established reference method.
Inference
The logical process of passing from observations to generalizations; the development of generalizations from sample data. Something that is inferred; especially : a conclusion or opinion that is formed because of known facts or evidence
Dry Mix
You can use the acronym Dry Mix to remember how to graph the variables. DRY = Dependent Responding Variable on Y axis MIX = Independent Manipulated Variable on X axis