1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Tesla's Experiment

  1. Sep 13, 2013 #1
    I am doing a very amateur version of Tesla's experiment of using potential difference between positively charged sky ( due to solar wind) and negatively charged earth. I took a piece of cardboard. Stapled aluminum foil to it to use as antenna. Stapled stripped end of wire to this foil and hung it over about 10 feet. Then I took another smaller piece of cardboard and buried it in wet ground. I attached one stripped end of another wire to it. Now I connected a capacitor between stripped end of wire from ground and antenna. As per theory, the capacitor should charge and develope some voltage. But this is not happening. Can anyone tell me where I am going wrong?
  2. jcsd
  3. Sep 13, 2013 #2
    I think the charge developed will be very less and would require an accurate measuring instrument.
  4. Sep 13, 2013 #3
    How can I increase charge?
  5. Sep 13, 2013 #4
    Lookout for a rainy and humid day.This will help the potential of the sky and clouds to be conveyed closer to the surface of our earth but be careful as there is a chance of lightning so don't touch any exposed wiring of your apparatus.
  6. Sep 14, 2013 #5


    User Avatar
    Gold Member

    sodaboy, It would be useful if you gave some reference for others to examine Tesla's experiment that you refer to.

    The solar wind may or may not be responsible for the charged atmosphere. As far as I can determine, there is no generally accepted of how this charge is originally formed. Thunderstorms are possible rechargers of the potential difference. Will you please give some reference please for this statement?

    Your experiment to charge a capacitor connected between ground and a higher altitude will not give you the measurement you seek. From the first Wiki page below: “To detect the presence of free electricity in the air a pointed metal rod projecting into the air several feet and connected at its lower end to a gold leaf electroscope may be used. When this rod is projected into the air a few feet the leaves diverge. Kites and balloons have also been used to detect and, so to speak, draw down the free electricity of the air.”

    A good place to begin your search is at these two Wiki pages. They give you the terminology, the units, their definitions, and provide a foundation of the basic physics on which you can build from.

    From the first Wiki reference:
    “Atmospheric electricity is the regular diurnal variation of the Earth's atmospheric electromagnetic network or, more broadly, any planet's electrical system in its layer of gases. The normal movement of electric charges among the Earth's surface, the various layers of the atmosphere, and especially the ionosphere, taken together, are known as the global atmospheric electrical circuit.

    There is a potential gradient at ground level ("Atmosphere ground layer") and this vertical field[44] corresponds to the negative charge in and near the Earth's surface. The negative potential gradient falls rapidly as altitude increases from the ground. Most of this potential gradient is in the first few kilometers. The positive potential gradient rises rapidly as altitude increases from the ground.” There is a huge wealth of information on this Wikipedia page towards the bottom. See “See Also”, “References and external articles”, “Journals”, “Other readings”, “Websites”, “Further reading”, and “External links”.
    See: http://en.wikipedia.org/wiki/Atmospheric_electricity

    From the second Wiki reference:
    “In electromagnetism, electric flux is the rate of flow of the electric field through a given area. Electric flux is proportional to the number of electric field lines going through a virtual surface.”
    See: (Edit) http://en.wikipedia.org/wiki/Electric_flux

    The earth's atmosphere fine-weather electric field is about 100 Volts/meter. The earth has a negative charge with reference to the atmosphere, which has a positive space charge. In fine weather (no storms) the voltage difference between the surface of the earth and the electrosphere at approximately 50 kilometers altitude is approximately 300,000 Volts.

    There several types of sensors that have been developed to measure these fields. The first is the electrostatic fluxmeter or electric field mill. This is an electro-mechanical device which measures the strength of a static electric field based on electrostatic induction. A grounded and segmented top plate rotates so as to cover and uncover a fixed , similarly segmented field-detecting plate beneath it. A quasi–static electric field is transformed into AC signals by means of periodic screening/unscreening of the sensor-based electrodes during rotation of the
    grounded plate.
    See: http://dsp-book.narod.ru/MISH/CH47.PDF
    And: http://a-tech.net/ElectricFieldMill/

    Other types of sensors are the Wilson plate, the horizontal long-wire antenna, the passive pair-hemisphere antenna of Burke-Few type. The charge induced on these antennas is sensed by an electronic circuit, often using a capacitor to ground or an integrator is used to integrate the current flowing to the antenna plate.
    See: H. Tammet, S. Israelson, E. Knudsen, T.J. Tuomi, “Effective area of a horizontal long-wire antenna collecting the atmospherc electric vertical current”, J. Geophys. Res., vol. 101, D23, pp. 29671-29677, 1996.
    See: http://onlinelibrary.wiley.com/doi/...sCustomisedMessage=&userIsAuthenticated=false
    Last edited: Sep 14, 2013
  7. Sep 14, 2013 #6


    User Avatar

    Staff: Mentor

    Bobby, your link to electric flux doesn't work. I don't think it's supposed to be "electric fluxy". :tongue:
  8. Sep 14, 2013 #7


    User Avatar
    Gold Member

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook