Tuesday, December 1, 2009

Tired of waiting for water to boil? You should try cold water!


Have you ever heard the saying "cold water boils faster than warm water?" Well I know I have, but I could never get myself to believe it because, is that physically possible? Well once you're done reading you will know whether warm water boils fast than cold water.

What makes cold water boil faster than warm is called the Mpemba effect. One may think that if you start boiling warm 70 degrees water, it would take less time then cold 30 degrees water because the warm water has a head start. This is untrue however. How can that be?

Here is a site by Monwhea Jeng who explains a detailed explanation of the Science

Well how it works is when you put cold water on a lit or turned on stove burner, the stove makes the cold water molecules move faster to get warmer. This makes the cold water warmer faster because its molecules are moving faster. As you know, friction creates heat and the water molecules are creating friction as they move against each other. If warm water was put on stove, the molecules wouldn’t move as fast, making it not warm up faster than the cold water. Even though this seems impossible it is very true. Another example of the Mpemba effect is when warm water freezes faster than cold water.

Over all sometimes what you think is what is not nessecary true. One example of this is the Mpemba effect. And maybe you’re even willing to try this for yourself at home, and if you do be careful, stoves are hot. Also, if you have any questions, concerns, or comments please post them below.

7 comments:

Soccer Stewy said...

I understand the science behind the Mpemba effect, and to some degrees it makes sense. however, it is very hard to get your mind around. THe other thing about the mpembe effect is that is very selective about the conditions under which it occurs, another reason to not believe it. however, i think i just might try it for myself.

casers54 said...

I think this is really interesting. Like Soccer Stewy said, the Mpemba effect does make sense, but just thinking about the process logically led me to think that warm water would boil faster than cold water, and cold water would freeze faster than hot water. Also, the other day I was watching Food Detectives and they tested this myth, but they had different results. The hot water boiled quite a bit faster than the cold, and they thought that the reason this myth came into being was that sometimes when water has been sitting in a hot water heater it has more impurities than the cold water, and that is why it is more advisable to use cold to cook with than hot. Here's the link: http://www.foodnetwork.com/food-detectives/index.html

Fork said...

This blog was very interesting to me because i do my fair share of cooking and i do not enjoy waiting for the water to boil. The Mpemba effect makes sense to me when cold water boils faster because the molecules are closer together but without really thinking about why it's true it would be hard to agree with such a statment like this one.

Anna2013 said...

I thought this was very interesting. At first I didnt think this could be much of a myth because to me, I expect that warm water would boil quickly. It seems more logical that warm water would heat up quicker than cold and cold would freeze quicker than warm, but once the Mpemba effect was explained, its easier to understand why that is not the case.

Hannah said...

I agree. This was very interesting. It still seems like logic though but you explained the Mpemba effect very well making readers understand the effect and why cold water boils faster etc.

Bethany13 said...

This myth didn't really suprise me but, that's only because I have heard of it before. However I was very suprised the first time I heard it, and I am kind of confused about the conditions. casers54 said that the impurities made one experiment have different results so is this one of those myths that sometimes works and sometimes doesn't?

casers54 said...

Sorry Bethany13, I didn't explain it very well. What I meant to say was that the t.v. show thought that the myth probably came into existence because people were worried about having impurities in their water, not that this caused the hot water to boil faster.