Marisol did an experiment to find out how long it takes for 100 mL of water to reach its boiling point. She placed 100 mL of water in a beaker and inserted a thermometer into the beaker. Then she placed the beaker on a hotplate, turned the heat setting to high, and started a stopwatch. She stopped the stopwatch as soon as the water reached its boiling point. The pictures below show what she observed at the beginning, middle, and end of the experiment.