Ask-a-Physicist by Topic

Electricity & Magnetism

Lifting with Static Electricity

Can electricity (static or not) be used to move very large objects? Could you somehow control a sufficiently strong electrical current through the air or across a surface to lift a log or a car? Are there certain objects it could lift and certain ones it couldn't?


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Super-Kamiokande neutrino detector in Japan. Image Credit: Univ. of Tokyo I am lost about neutrinos. I thought a neutrino was just a neutrino since it is neutral. What are the differences between electron, muon, and tau neutrinos?
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Water as a dipole showing the slight charges Since water molecules are negatively charged on one side and positive on the other, can you freeze a container of water which you place in a magnetic field and create an ice-magnet?
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sandanimation

I built a sand art box for performing sand art but I have a problem. The sand I use keeps bouncing around on the glass as opposed to being pencil thin. How or what kind of sand can I use to remedy that?


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Crank

How can you make electric currents from magnets?


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array How is the photoelectric effect used to produce a current in a photovoltaic cell?
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microwave Why does aluminum foil spark in the microwave? - BB, Iowa City, IA
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switches Some lights in my home are controlled by two different switches. How is this possible? - V
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cables Why is it that when you severely kink an Ethernet cable, you can no longer transmit data on it? That cable contains 4 twisted pairs of copper wires and kinking the cable doesn't break or short out those wires. Why should the kink matter? - DB, Evansville, Indiana
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toothbrush My electric toothbrush charges up by sitting in its base unit. There is no metal-to-metal contact—only plastic-to-plastic. Since the plastic is non-conductive, how does it charge? – RS
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storms After a tropic thunderstorm, why does it feel so nice to breath? - WM, Kota Baru, Kelantan, Malaysia
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brightness For a science project, I made a parallel circuit and a series circuit. Each is powered by a 6.3-volt battery and has three six-volt lights on it. Why is the series circuit so much dimmer than the parallel circuit? - ML, Woodbridge, CT
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Generator Why does an electric generator slow down when you begin to use the power it is generating? – WV, Waverley, South Africa
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motor If you coupled a motor to a generator and connected them to the same power source, would the generator be able to recycle wasted power from the motor and thereby reduce costs? — JH, Australia
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wind I'm studying how wind power is used to produce electricity and would like to know how a generator works. - MO, Canandaigua, New York
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beam An electron beam, such as the one found in a TV picture tube, is composed of negatively charged electrons. Why is it that this beam does not rapidly spread out owing to the electric repulsion? I realize that the tube has various focusing magnets and such, but I would think the electronic repulsion would be a serious problem. - JT, Buffalo Grove, IL
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