Resistance between finger and Earth wire

i connected one probe of DMM to the earth terminal of single phase ac mains supply and held the other probe. dmm displays resistance of 1.7Mohm .
but when i touched that probe (one i'd held) to the floor. it displays >200Mohm. why so ? shouldnt resistance be lesser?
doesn't any current flow if the live wire is in direct contact with the floor ?
Tried the same experiment by putting the probe into a small area of water on the floor
DMM showed 2.3 Mohm
also tried with a steel plate between the floor and probe, shows ~12 Mohm impedance

On the basis that the probe to floor reading was >200Meg it suggest either the floor is an effective insulator or the point contact area was so low that you had in effect a high resistance contact. If the former then when you held onto the probe, because the DVM is a high impedance device, it may actually have been influenced by the "radio" signals induced into it by your body acting as an aerial (antenna).

One of the problems of measuring high resistance with a DVM on circuits that can themselves generate small bio-voltages (your body for example) is that readings can be fairly meaningless.

"Proper" resistance measurement can better be established by injecting a known relatively high current (several tens of milliamps) and measuring the voltage required to inject the current or to apply a known high voltage (500 volts or so) and measuring the current flowing.

There is another possibility. there may be some capacitive coupling to the AC power. If the meter acted as a diode, it could have caused a slight voltage drop on the probe that registered as a current.

Your body acts as an antenna picking up all sorts of signals, from mains to local radio to motors and many more things. This injects voltages into a high impedances setup like this and gives meaningless results.

jackrae:
On the basis that the probe to floor reading was >200Meg it suggest either the floor is an effective insulator or the point contact area was so low that you had in effect a high resistance contact. I

it must have to do with contact surface area with the floor
liquids provide larger contact surface area. occupy all unevenness
same does with sweat on human skin
a flat steel plate on the floor doesnt provide that large a surface area of contact

SumitAich:
i connected one probe of DMM to the earth terminal of single phase ac mains supply and held the other probe. dmm displays resistance of 1.7Mohm .
but when i touched that probe (one i'd held) to the floor. it displays >200Mohm. why so ? shouldnt resistance be lesser?
doesn't any current flow if the live wire is in direct contact with the floor ?
Tried the same experiment by putting the probe into a small area of water on the floor
DMM showed 2.3 Mohm
also tried with a steel plate between the floor and probe, shows ~12 Mohm impedance

The DC resistance at a volt or so as measured by the multimeter bears little relation to the resistance at 240Vac,
where cell walls (in human skin and in wood) break down and the conductivity can increase rapidly. Human skin can also react by opening the pores and letting the current flow direct into the sweat-glands, a very much lower resistance path.
Put another way humans and wood do not obey ohms law very well. Wood in particular is strongly affected by the humidity levels, in a centrally heated building it will be a far better insulator than if exposed to the weather,
for instance.

to summarize all possibilities -
1.

jackrae:
On the basis that the probe to floor reading was >200Meg it suggest either the floor is an effective insulator or the point contact area was so low that you had in effect a high resistance contact.

jackrae:
One of the problems of measuring high resistance with a DVM on circuits that can themselves generate small bio-voltages (your body for example) is that readings can be fairly meaningless.

SumitAich:
There is another possibility. there may be some capacitive coupling to the AC power. If the meter acted as a diode, it could have caused a slight voltage drop on the probe that registered as a current.

Grumpy_Mike:
Your body acts as an antenna picking up all sorts of signals, from mains to local radio to motors and many more things. This injects voltages into a high impedances setup like this and gives meaningless results.

SumitAich:
it must have to do with contact surface area with the floor
liquids provide larger contact surface area. occupy all unevenness
same does with sweat on human skin
a flat steel plate on the floor doesnt provide that large a surface area of contact

6
also the actual potential of the earth terminal and the point of earth that is measured to may not be equal, IOW a very small current could be present.