When do we use experimental design? Experimental design is used to answer scientific questions by testing a hypothesis through the use of a series of carefully controlled steps.

What is bias?Bias occurs when you make certain decisions, or record specific data, to get the result you want. These are graphs that show bias.

How do you eliminate bias ? When you choose samples, you can eliminate bias by ensuring that all conditions (variables) are tested.

What is a variable?A variable is a factor or an attribute, a characteristic of an object. Example: soda Variables: the amount of sugar, the amount of caffeine

What is an independent variable? The independent variable is the one that is changed by the scientist. There should only be ONE independent variable. Example: We have to choose to change either the amount of sugar or the amount of caffeine, but NOT BOTH. Types of Variables

What is a dependent variable? The dependent variable is the factor being measured. This is what the scientist is observing and recording. Example: The heart rate of a person after consuming the product (under the same circumstances). Types of Variables

What are constants? (also called controlled variables) Constants are the variables that stay the same. Example: The amount of soda consumed, the temperature of the soda, the time of day the soda is consumed, the person consuming the soda, and the instrument used to measure heart rate must all be constant. Types of Variables

What is a control?A control is a sample that is treated like all the other samples except that the independent variable is not applied.. Example: Water would be a good control because it does not have sugar (the independent variable). Types of Variables

What is a trial?A trial is when you perform the experiment. Example: The picture shown would be one trial. Because doing the experiment the same way might not always give the same result, you should do multiple trials.