Experimental Design

Scientific questions should be written in which general format?

• How does the Independent Variable affect the Dependent Variable?

• How does the Controlled Variable affect the Dependent Variable?

• How does the Independent Variable affect the Controlled Variable?

• How does the Dependent Variable affect the Independent Variable?

Which is the correct format for a hypothesis?

• If DV then IV because ...

• Because IV I think DV will occur

• I think the IV will affect the DV because ...

• If IV then DV because ...

You are given this question to investigate: How does adding solute to water change the temperature at which the water boils?

What is the dependent variable in this question?

• Adding solute to water

• Temperature that water boils

• Amount of solute in water

• Amount of water being boiled

Identify the independent and dependent variable in the following hypothesis:

If the concentration of sugar dissolved in water increases the water will take longer to boil because dissolved solutes slow the energy transfer and increase the boiling point.

• Concentration of sugar/time to boil

• Time to boil/ concentration of sugar

• Boiling point/time to boil

• Time to boil/boiling point

Why did Carol use 5 seedlings instead of a single seedling in each group?

• To ensure that her investigation is a controlled experiment (or fair test).

• To increase the confidence that the results are not by chance.

• To show that any difference in the results is due to the color of light.

• Because the lab manual said to run at least 5 trials.

The set-ups are left at room temperature for two days. To investigate whether light is necessary for seed germination, which of the set-ups should be compared?

• (1) and (3) only

• (1) and (4) only

• (2) and (3) only

• (2) and (4) only

a correlation describes...

• a positive relationship between two variables

• a negative relationship between two variables

• a relationship between two variables

• a random event

The variable that responds to the changes in the other variable is the ___ variable.

• Independent

• Dependent

• Constant

• Control

A set of conditions that can be used as a baseline

• Independent

• Dependent

• Constant

• Control

What is the independent variable on this graph?

• Year

• Number of Visitors

• Visitors to a Park

• none of these