# Electrical charge from air coming from a furnace vent, positive or negative?

#### Arealperson

Joined Mar 25, 2013
2
Hypotheses:
The warm air coming into my room through the floor vent from my gas furnace has an electrical charge I think.

Experiment Test:
I blow up a balloon (No rubbing, or anything else) and just place it over the heat vent, the force of the air should blow the balloon far away,
however, it only causes the balloon to hover slightly above the vent.

Q1:
Does anyone know what charge the Balloon and/or the warm air would be (POS or NEG) ?
Q2:
How could simply check the air from the vent to tell what the charge is (NEG or POS) ?
Q3:
What other simple experiment (if any) would prove my hypotheses?

Thanks

#### JohnInTX

Joined Jun 26, 2012
4,198
It might just be that the balloon is held in the column of rising air by Bernoulli's principle. Moving air has a lower pressure than stationary air. The higher pressure ambient air around the balloon holds it in the lower pressure moving column. The momentum of the air hitting the bottom of the balloon provides lifting force in the column. See pp15 of the .pdf.

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#### BobTPH

Joined Jun 5, 2013
2,493
If the balloon is spinning, John is probably right.

Bob

#### crutschow

Joined Mar 14, 2008
25,247
If air is charged it's usually because the air molecules lose an electron.
That make the air positively charged (positive ions).