EXPERIMENTAL DESIGN Science answers questions with experiments

based upon your observations Do background research DEFINE THE PROBLEM based upon your observations Do background research

Now we need a hypothesis to guide our investigation. What is a hypothesis? No, It is NOT an educated guess! Your best thinking about how the change you make might affect another factor. Tentative or trial solution to the question. An if ………… then ………… statement.

Variables Variables are things that change. The independent variable is the variable that is purposely changed. It is the manipulated variable. The dependent variable changes in response to the independent variable. It is the responding variable.

Factors that are kept the same and not allowed to change Constants in an Experiment What are constants in an experiment? Factors that are kept the same and not allowed to change

The part of the experiment that serves as the standard of comparison. The Control in an Experiment What is a control? The part of the experiment that serves as the standard of comparison. Why is a control necessary? It is the unchanged part of the experiment that detects the effects of hidden variables.

Experimental Group The group exposed to the conditions of the experiment control group is not exposed to experimental conditions experimental group is exposed to experimental conditions

Independent Variable – include units and an appropriate scale Graphs Title: The Effect of the independent variable on the dependent variable Dependent Variable – include units and an appropriate scale Independent Variable – include units and an appropriate scale

Remember DRY MIX D = dependent variable R = responding variable Y = graph information on the vertical axis M = manipulated variable  I  = independent variable X  = graph information on the horizontal axis

Beriberi: I cannot, I cannot It is 1897 and people are dying in Java, an island in Indonesia or the Dutch East Indies. They all seemed to share the same hideous symptoms beginning with overall muscle weakness, loss of appetite, and eventually they suffered paralysis and eventually death by heart failure. This disease was called beriberi by the indigenous people. This was a word from their native language that meant “I cannot, I cannot.” Scientists thought the disease might be caused by bacteria. (After all, since the discovery of bacteria, almost all previously unknown diseases were attributed to a bacterial infection.)

Authors Harry Dillner, Kathy Melvin Delaware Science Olympiad Modified by G. LaBruyere 9/9/13