Controlled Variables

The variables that i kept the same when collecting, and completing my investigation included:

• Where the samples came from - Gunnamatta Bay
• The time the samples were taken - between 5 and 6pm
• The amount of times each sample was tested - Twice
• The amount of water demineralised water (where required) added
• How long the pH probe was left to read of the pH of the samples - 1 minute
• How long the soil samples were kept in the oven during moisture, organic content testing
• The teperature of the oven during moisture and organic content testing
• The size of beakers and filters used kept the same for each individual test