Next, you’ll test your hypothesis by examining the reaction times of vinegar and baking soda in boiling water using four different concentrations of the reactants. You’ll vary the concentrations by using tablespoon (7.5 milliliters), 1 tablespoon (15 milliliters), tablespoons (22.5 milliliters), and 2 tablespoons (30 milliliters) of water. Note that you will use the same amounts of vinegar and baking soda for each trial. Gather all the materials, and proceed with these steps:

Boil at least 1 cup (240 milliliters) of water on a stove, on a hot plate, or in a microwave oven.
Measure and record the actual temperature of the water.
Measure the required amount of boiling water into the cup.
Add teaspoon (1.5 grams) baking soda to the water, and stir until it is dissolved. The resulting solution will be clear.
Measure out 1 tablespoon (15 milliliters) of vinegar, but do not pour it into the cup yet.
Very quickly, do all of the following:
a. Pour the measured vinegar into the cup.
b. Start the stopwatch.
c. Stir or carefully swirl the substances in the cup.
The chemical reaction will produce bubbles. You’ll be able to see the bubbles and hear them pop. Watch and listen for when the reaction stops. When it looks and sounds like it has finished, stop the stopwatch.
Record the reaction time in the data table.
Discard the solution down the drain, and rinse the cup.
Repeat this procedure, doing three trials at each concentration. Record the average temperature and reaction time for each set of the three trials. Read this math review for a refresher on finding averages.