Collecting data in any experiment involves making observations. You first must decide what type of data you must collect. Data (information) can be either quantitative or qualitative. All data is entered in ink into the Project Log Book.

Collecting quantitative data involves using scientific instruments to make measurements. Any measurement calculated in any scientific experiment always involves the metric system!! Never use yards, ounces, feet, inches, gallons, mph, or any other standard unit!! The data is usually collected and organized into a table so that it can be interpreted easily.

Some examples of quantitative data:

Collecting qualitative data involves involves making observations, but does not involve measurements. To collect and present data for a qualitative experiment, one must make a "rating scale" with specific definitions. For example, if an experiment was done on how different types of soft drinks effect the decay of teeth, there is not a "clear" way to "measure the decay of a tooth". One would have to take photographs of the teeth, and develop a specific rating scale defining the amount of decay. The rating scale would include numbers which could be graphed. See the example below.

0- no decay present (no color change and no change in texture and hardness of the tooth)
1-slightly decayed (slight color change or change in texture, tooth has become slightly softer)
2- moderate decay (definite color change or change in texture, tooth is moderately softer)
3-prominent decay (drastic color change and change in texture, tooth is very soft)