Three Types of Science Investigations - Denton ISD

[Pages:1]Three Types of Science Investigations

Vocabulary

Hypothesis: an educated prediction that can be tested. It describes in concrete terms what you expect will

happen in a certain circumstance.

Theory: an explanation that has been tested many times, resulting in the same conclusion.

Variable: factor or condition in an experiment that changes or can be changed.

Independent/Manipulated Variable: factor or condition in an experiment that is changed on purpose by you, the scientist. This goes on the X axis of a graph. (Bottom)

Dependent/Response Variable: factor or condition in an experiment that changes as a result of the independent variable. This is what you measure and goes on the Y axis. (Side)

Constant: factors or conditions that are kept the same in all trials of the experiment.

Control: a set up without the variable being tested.

Descriptive Investigation:

Involve describing and/or quantifying parts of a natural system.

Example ? Measuring the width of a desk with a meter stick. Has a research question, procedures, and conclusion Used when little is known about the topic No hypothesis or prediction Key words: Observe, describe, list, identify

Example Question: _____What happens when a piece of potato is added to hydrogen peroxide?_________

____________________________________________________________________________________________________________________________

Comparative Investigation: Involve collecting data on different populations/organisms, under different conditions (ex. Times of year, locations), to make a comparison. Example ? Using a hand lens to examine the color and texture of four different rocks.

Has a research question, possible hypothesis, procedures, and conclusion. Can have independent/manipulated and dependent/response variables No control / control group Key words: Compare/contrast, similarity/difference, categorize

Example Question: ____ Which vegetable shows the greatest reaction with hydrogen peroxide?_________

____________________________________________________________________________________________________________________________

Experimental Investigation: Involve a designed test in which variables are changed, controlled, and measured in an effort to gather evidence to support or disprove a hypothesis. Example ? Planting rye grass seeds in potting soil in three plastic cups, placing them on a window sill, and watering one daily, one every third day, and one not at all.

All known variables have been identified Has a research question, hypothesis, procedures, control, and conclusion Has independent/manipulated and dependent/response variables All factors can be held constant except the manipulated

Example Question: __How does the amount of potato affect its reaction with a fixed amount of ________

__________________hydrogen peroxide?_________________________________________________________

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