Jack wants to find out which laundry detergent cleans the best (Gain, Tide, or Purex). So, he takes a
cotton sheet and cuts it up into equal squares. He stains four squares with chocolate, and four with
grape juice. He washes one of each of the squares in each of the 3 detergents. One from each set of
squares is washed in water alone. For each wash load, he used: the same amount of water, the same
amount of detergent, and the same temperature of water.
■ Independent variable: ■ Dependent variable: ■ Control: ■ Constants:
Independent variable: Type of laundry detergent (Gain, Tide, or Purex)
Dependent variable: Cleanliness of the stained squares
Control: Washing one square from each set in water alone
Constants: Amount of water, amount of detergent, temperature of water, type of stains (chocolate and grape juice), size of squares
Independent variable: The different laundry detergents (Gain, Tide, Purex)
Dependent variable: The cleanliness of the stained squares (how well the stains are removed)
Control: The square washed in water alone
Constants:
- The same amount of water used for each wash load
- The same amount of detergent used for each wash load
- The same temperature of water for each wash load
- The same type and size of cotton squares used for staining