The Three Types of Investigations: Descriptive Comparative Experimental

Descriptive Investigation Describing and/or quantifying parts of a system

Descriptive Investigations Involves describing and/or quantifying (counting) parts of a natural or man-made system.

Descriptive Investigations An investigation used to explore questions in environmental conditions you cannot control. Ex. Jane Goodall’s study of chimpanzees. Picture hyperlinked to: www.janegoodall.org/media/videos A hypothesis is not required in these investigations.

Comparative Investigation Collecting data on different organisms, objects, or features, or collecting data under different conditions (e.g., times of year or locations) to make a comparison

Comparative Investigations Involves collecting data on different organisms, features or collecting data under different conditions (For example, times of year, temperatures, locations)

Comparative Investigations Involves collecting data on different organisms/objects/features, or collecting data under different conditions to make a comparison. Example: times of year, temperatures, locations Hypothesis: Pecan trees produce more pecans during the rainy season than they do during a drought.

Experimental Investigations Involves designing a fair test in which variables are actively manipulated, controlled and measured in an effort to gather evidence to support or not support a hypothesis.

Experimental Investigation A fair test in which variables are manipulated, controlled, and measured to gather evidence to support or not support a hypothesis

Does the amount of fertilizer effect plant growth? Research Question: Does the amount of fertilizer effect plant growth Hypothesis Ex: The more fertilizer a plant recieves the faster it will grow. Gathering Data: Controlled experiment with one independent variable.

Variables – When doing a science experiment, there are things that you, as the scientist, control to make sure your test results are dependable Constants – are the things that stay the same in an experiment.   Control – is the trial/part/ thing that the other trail are compared to. The control in an experiment on how fertilizer effects plant growth would be the plant without fertilizer. If in doubt, the control is usually the first trial in the experiment.

Terms Used in Investigations Independent Variable or Manipulated Variable – The independent variable is the thing that you change in the experiment. All the other things in your experiment should stay the same. For example, in an experiment on how the amount of fertilizer effects the growth of plants, the independent variable is the type of fertilizer. We’ll use the same kind of pot, soil, and plant. We’ll have the plants get the same amount of light and stay in the same room at the same temperature. We’ll add the same amount of water. The only thing that will change is the kind of fertilizer. Dependent Variable or Responding Variable – The dependent variable is the thing that changes because of the independent variable. For us, that would be the height of the plant. The height of the plant changed because we changed the type of fertilizer.