| |
|
|
Science Words
hypothesis: a
statement that can
be proved or disproved
by experimental or observational evidence
relationship: an idea about what happens
to one variable when
a second variable changes
manipulated variable(also called independent variable): in an experiment, a variable that can be deliberately changed by the scientist and that determines
the values of other variables (called responding variables)
responding variable (also called dependent variable): in an experiment, a variable that responds to the change in the values
of the manipulated variables. The scientist cannot set the values
of the manipulated variables directly.
fair test: an experiment in which only the manipulated and responding variables are allowed to change and all other variables and conditions are kept the same |
|
|
Sometimes, the hypothesis a scientist wants to test concerns the relationship between two variables. A relationship is an idea about what happens to one variable when a second variable changes. The first variable may increase, decrease, or change in some more complicated way. Or it may not change at all, in which case there is no relationship between the two variables. To test their hypothesis about a relationship between two variables, scientists deliberately change one variable and measure what happens to another variable.
- •The variable that is deliberately changed in an experiment is called the manipulated variable (also known as the independent variable).
- •The variable that responds to the change (the variable that you measure) is called the responding variable (also known as the dependent variable).
An experiment is a fair test when both of the following are true:
- •only the manipulated and responding variables are allowed to change
- •all the other variables and conditions in the experiment are kept the same. (They are controlled.)
Discuss the following questions with your team and write your best answers on your record sheet.
- 7.In the experiment involving three magnets of the same material, what was the manipulated variable? What was the responding variable?
- 8.In the pendulum experiment, what was the manipulated variable?
What was the responding variable?
My Ideas
The key question for this activity is:
 |
What makes the design of an experiment good or poor ? |
- Based on what you learned in this activity, write your answer to the key question.
 Participate in a class discussion to review the answer to this question.
|
