EXPERIMENTAL DESIGN

A good, valid scientific experiment will:

• have at least 3 trials (enough for a pattern to be seen)

• only have two variables

  • an independent variable that the scientist can control

  • a dependent variable that the scientist can't control but that can be measured

• have everything else involved in the experiment stay the same (constant)

• have a different value for the independent variable each trial

ALKA-SELTZER LAB PROBLEM

Our first lab's problem is:

Problem:

Determine the relationship between the amount of Alka-Seltzer used and the amount of carbon dioxide (CO₂) produced.

Requirements:

• You must use (at least):
• one pair of tongs
• one Alka-Seltzer tablet (maximum is 3 per group)
• one test tube rack
• one test tube
• one balloon
• some water
• Alka-Seltzer may not touch your hands or the table.
• You must complete three trials of the same experiment.
• You must change the value of the independent variable each trial.