Water not conducting in my experiment

[linux kid]

Last night my cousin and I were arguing the conductivity of water. I was taught that water is a conductor of electricity, but he claims otherwise.

So, we did a simple experiment using tap warm water, a 1.5v battery and small light bulb. It refused to conduct and the light bulb would not light.
We tried this on the - and + wires and my cousin claimed victory.

So what went wrong. Either I had a horrible teacher or I was just dreaming...

 

[Hootenanny]

Pure water is non conducting as is most tap water. It is the dissolved ions in solution that allow water to conduct. For example copper has an electrical conductivity about 1.2 x 10⁹ times greater than drinking water.

 

[Integral]

Actually Tap water is not to bad of a conductor, if you had used a ohmmeter to conduct the test instead of a 1.5V battery and a light bulb, you would have incorrectly won the argument.

The fact remains that clean deionized water is a non conductor. It is also a fact that such water does not exist naturally. The deionization is temporary as a small percentage of water molecules tend to ionize naturally. DI water systems consist of plastic pipes and must be kept flowing continuously as to filter the natural ions which occur.