Boiling water more efficiently

[Warp]

While boiling water, I was thinking: Would one liter of water boil faster or slower if I boil it all at the same time, or if I do it in stages, ie: First boil one deciliter, then add a deciliter and wait it to boil, and so on until there's one liter of boiling water.

Stated a bit more formally: Suppose you have 1 liter of water at a certain temperature (just for the sake of example let's say 10 degrees celsius) and you have a hot plate and a pot, and you want to raise the temperature of the water to 100 degrees celsius. Two different methods are tested:

1) Just put the 1 liter of water in the pot, and wait for it to reach 100 degrees.

2) Add 1 dl of water to the pot, wait for it to reach 100 degrees, and repeat this 9 more times.

Which of those methods would be faster, or does it make any difference?

 

[mathman]

As a practical matter, it takes longer to do it in steps, because of the transitions. Ignoring that it would take the same amount of time because the heat quantity needed is the same.

 

[voko]

Doing that in steps increases the heat exchange with the environment, so not only does it take longer, it wastes more energy.

 

[mikeph]

Not to mention the above two answers, in the second scheme you will lose energy via surface evaporation at each stage.

 

[PJC01]

I would approach this question by considering the principles of thermodynamics and heat transfer. The time it takes for water to boil is dependent on several factors, including the amount of water, the starting temperature, and the amount of heat applied.

In the first method, where 1 liter of water is boiled all at once, the water will reach its boiling point faster because all of the water is being heated at the same time. This is due to the fact that heat transfer is more efficient when there is a larger temperature difference between the object being heated and the source of heat. In this case, the initial temperature of the water is 10 degrees celsius, so the difference between that and the desired boiling temperature of 100 degrees celsius is larger than in the second method.

In the second method, where 1 deciliter of water is added and heated at a time, the water will take longer to reach its boiling point. This is because each time water is added, the overall temperature of the water decreases, and it takes longer for the added water to reach the boiling temperature. This results in a longer overall heating time.

Therefore, it can be concluded that the first method of boiling 1 liter of water all at once is more efficient and will result in a faster boiling time compared to the second method of adding water in stages. Additionally, it is worth noting that the type of pot and hot plate used can also affect the efficiency of boiling water. A pot with a larger surface area and a more powerful hot plate will typically result in faster boiling times.