Is Earth an insulator or an conductor?

Answer 1

Firstly, it is better to categorize things into good and poor conductors, not insulators, because 'insulators' like cloth can conduct electricity if the latter is passed through the cloth in high quantity.

Now, coming to your question, Earth can mean two things--soil or the planet Earth. Considering soil, it is a poor conductor. Place a lump of soil in a gap in a circuit and you will not see the bulb glowing. Soil will not conduct any electricity. But the planet Earth has both poor and good conductors on its surface. Below is molten rock. You cannot really say what kind of conductor our blue planet is. It's a little bit of both. so i'd really say it's a fair conductor.

Answer 2

Pure or distilled water does not conduct electricity. Contaminants or impurities in the water cause it to conduct electricity such as salts. For the same reason you do not want to microwave distilled water because it will not boil but become superheated. When you break its surface tension, it will kind of burst covering you with superheated water.

Answer 3

The Earth may act as an dielectric or a conductor depending on how you choose to measure it.

Electrical resistivity is a common mineral exploration tool.

Ground Penetrating Radar uses changes in the dielectric constant to perform its measurement or detection of old graves or pipelines or similar discontinuities in the subsurface.

Answer 4

Absolutely

Answer 5

Yes.