Scientific Experimental Challenge #2

What would be an independent variable in an experiment where the testable question is, "Which paper towel brand is the strongest?"

• brand of paper towel
• amount of weight placed on each towel
• number of times each brand is tested
• strength of the paper towel

What would be a dependent variable in an experiment where the testable question is, "What level of salt works best to hatch brine shrimp?"

• The number of brine shrimp eggs placed in each salt solution
• The amount of salt used in each solution
• The number of brine shrimp that hatch in each solution
• The temperature of each salt solution

BooBoo believes that his plants grow so well because he is always playing music in his room. What is a question he might ask to test this?

• Does music have an affect on plant growth?
• Which music groups like plants?
• Does plant growth make music sound better?
• Why do dying plants hate music?

Which variable values should you know before you start an experiment?

• Dependent Variable
• Independent Variable

The size of the plant would be the dependent variable for an experiment for which of the following testable questions?

• What light brightness makes plants grow the largest?
• Does plant size affect the amount of carbon dioxide that is absorbed?
• Which fertilizer makes plants grow the fastest?
• Which types of plants will die in mercury-polluted soil?

How does watching TV during studying affect a student’s test grades?

• independent
• dependent

Butter bean seeds were placed in petri dishes lined with moist paper towel for 5 days at different temperatures & germination was measured.  Which of the following is the independent variable?

• Number of seeds
• Time
• Temperature
• Type of seed

Does the temperature of water affect the time it takes a sugar cube to dissolve?

• IV: Type of water
  DV: Dissolving rate
• IV: Temperature of water
  DV: type of sugar cube
• IV: Temperature of Water
  DV: Dissolving Rate
• IV: Time
  DV: Number of sugar

Mr. S. sets up an experiment to see how the mass of a ball affects the distance it rolls off a ramp.  Identify the constant.

• distance traveled by the ball
• height of the ramp
• mass of the ball
• weight of the ball

Does the flavor of ice cream effect how fast the ice cream melts?

• independent
• dependent