Defining the Variables

Bath Bomb Project

Making Accurate Measurements

Making accurate measurements is key to getting high quality results. Depending on what you are measuring, you should consider how you might measure the variable as accurately as possible. Some examples include:

  • Measuring the amount of fizz: Hold a measuring jug upside-down and filled with water over the bath bomb to catch the gas released
  • Measuring the time taken for the bath bomb to dissolve: use a (waterproof!) stopwatch
  • Measuring how nice the smell is: get your family and friends involved - each give a rating out of ten then average the results

Using a Table

We would recommend using a table to record your results if possible. Tables are particularly useful for numerical data, but other observations can also be written in.

The headings on a table are very important. The first should be the independent variable (what you are varying), while the second should be the dependent variable (what you are measuring). If your table contains numerical values, don't forget to include the units in the header of the table. If you are planning to carry out repeats you can include multiple columns in the dependent variable section.