The electrolysis of water is formed by producing an electric current through water that causes the reaction: [math]H_{2}O (l)[/math] ---> [math]H_{2}(g) + O_{2}(g)[/math].

 

When water is heated, the following occurs:

[math]H_{2}O (l)[/math] ---> [math]H_{2}O (g)[/math]

It turns into vapor.

 

Doesn't electricity product heat? So shouldn't that heat evaporate the water instead of decomposing it?

It's not boiling the water. Take a look at the Wikipedia article.

Is electrolysis the only method to decompose water?

Is electrolysis the only method to decompose water?

 

 

If you want both components, you should be able to bombard it with light of sufficient energy and form the constituents. This is known as photolysis, and may include (or require) some other chemicals to occur efficiently.

 

http://adsabs.harvard.edu/abs/2004APS..MAR.m1005G

http://www.jstor.org/pss/36610

 

 

If you want just one component then a material that bonds more strongly with the other will suffice, e.g. Aluminum reacts with water to form an oxide and H2.