Does Salt Make Water Boil Faster?

I have loved cooking since I could remember. I have always enjoyed watching the culinary process and jump on an opportunity to cook whenever I can. Through the years, I have noticed that some people always throw table salt into their pan of water before boiling. They always say it makes the water boil faster, while others insist that it makes the water boil slower keeping the water from boiling over. Does salt really make the water boil faster? Is the extra sodium really worth it? I decided to perform a series of tests using the scientific method to see if water will boil faster with regular table salt added.

To test this question, I began experimenting and collecting data. This was done in my kitchen with water, salt, a pan that I allowed to cool down between the boiling times, a thermometer, and of course, my gas stove. I did the experiment three times without salt and three times with salt to get a more accurate reading.

Here is the data from the experiment:

6 cups with no salt took 8 min 24 sec
6 cups with no salt took 8 min 9 sec
6 cups with no salt took 8 min 19 sec

6 cups with 1 Tablespoon salt took 7 min 23 sec
6 cups with 1 Tablespoon salt took 7 min 31 sec
6 cups with 1 Tablespoon salt took 7 min 27 sec

As the data reflects, water, with salt added, boils about one minute faster than water without salt. During the boiling process, I noticed that the water with salt added had small, tight bubbles very quickly, while the water with no salt took longer to form bubbles. Also, the water with no salt had bubbles that were larger and seemed more chaotic. I was still left with the question of why this happens. I know that salt added to ice makes it melt, and water with a high salinity causes more buoyancy, but I was unfamiliar with the scientific reason behind the data I had collected.

Looking at my data, I could clearly see that salt in the water shaves, on average, one minute from the cooking time. This is not much of a difference, but it still proves that salt makes a difference in the time it takes to boil water. Why does this happen? Put on your thinking caps! We are about to look at the scientific reasoning behind the salt in boiling water phenomenon. For your convenience, I have included the scientific explanation first, followed by the translation into everyday language in bold print.

A water molecule is made of a negatively charged oxygen atom and two positively charged hydrogen atoms. When water is heated, these bonds begin to weaken since more energy is being added. This creates a microscopic cavity void of all water molecules. These microscopic cavities combine to form bigger cavities which lead to molecules of water being released into the atmosphere, or what is known as the boiling point. Or, in other words, bubbles form and steam is released at boiling point. When salt is added, molecules begin to move around at random increasing the temperature at which water will boil. This means that the water is boiling hotter so it reaches the boiling point faster. In other words, when salt is added to the mix, the molecules start to move around rapidly and randomly making the water temperature rise and the water to boil faster.

From this experiment I gathered that cooking with salt does make a small difference, albeit, not by much. With this mind, I think next time when I am cooking, I'll just skip the extra sodium.

Sources:

http://www.abc.net.au/science/articles/2007/04/12/1894612.htm?site=science/greatmomentsinscience

http://www.wwnorton.com/catalog/spring02/001183excerpt.htm