Boiling water question

[concrete_hed]

When you boil water, if you watch it from the very beginning when you apply the heat, you will notice that some very small bubbles appear at the bottem of the beaker (or whatever your boiling it in). The bubbles slowly grow larger and finally when they are too big they pop up to the surface. When the water is boiling vigorously, there is lots of bubbles all coming up from the bottem very quickly.

 

It may sound like a stupid question but i want to know what those bubles are. I know that water is made of hydrogen and oxygen and i know about electrolysis. Is this process similair to electrolysis, splitting water up into hydrogen and oxygen?

[JustStuit]

Those bubbles are water vapor, no chemical reactions just a physical change in state of matter. Some of the water is turned into a gas. They probably appear at the bottom because the metal and the water right around it have the highest temperature so it is the first to pass the the boiling temperature.

[5614]

Yep.

 

You know when you heat water is evaporates. Well in a beaker the flame or heat source is at the bottom so that is where the water starts evaporating first. So now you have gas "water" at the bottom of the beaker. This is obviously light than water so it rises as a bubble.

 

As the water gets hotter there is more water evaporating the whole time so the bubbles get bigger because there is more gaseous "water" in the water.

[Exocet]

If you think about it, its got to be gaseous water really...

because if you had hydrogen and oxygen being heated in a pan in your kitchen, you'd have no kitchen left at the end of it...

[Callipygous]

If you think about it' date=' its got to be gaseous water really...

because if you had hydrogen and oxygen being heated in a pan in your kitchen, you'd have no kitchen left at the end of it...[/quote']

 

 

nah... all of it would be hot, and therefore would move up away from the ignition source. once out of the pot it would go straight to the ceiling, and then spread out in the rest of the air in the room. to get enough to raise the concentration of an entire room to a combustable mixture would take way more than a pot.

 

(wooooot!! 2^10 posts!)

[swansont]

The very first bubbles you get are whatever gases are dissolved in the water coming out of solution. You might notice that, as the water heats up, it makes some noise and then the pot gets quiet again. Then the boiling begins. The first noise is the dissolved gases, the second is the water vapor.